THE CONODONTA

G- lesources,and Morphology,Taxonomy, Paleoecology, andEvolutionary History of a Long-ExtinctAnimal Phylum 3 azI High-pressure WALTERC.SWEEL EE: TheOhio State University fIt;:t F

by the -i-:ztlog' fr, :.1 a olution- b.-;:n-

New York . Oxford CLARENDON PRESS. OXFORD . 1988 PREFACE

Conodonts are common fossils.Almost anyone portant group, I ofer my account of the who dealson a regularbasis with Paleozoicand Conodonta. Triassic marine rocks has probably seena few For their "witting" or unwitting contribu- of them. Through the last 30 yedrs conodonts tions to what I believe I know about the fasci- have come to be of exceptionalvalue in bio- nating gtoup of extinct animals described on stratigraphy, and they now have pride of place the following pages,I am gateful to a long list as index fossils in many parts of the geologic of my students and faculty colleaguesat The column. But conodonts are extinct and are un- Ohio StateUniversity, especiallyStig M. Bergs- knowo to most neontologists. The sketchiness trijm, and to members of the Pander Society, ofinformation about them in most texts on in- an intemational group of exceptionally good- vertebrate paleontology may result either fiom natured "conodontologists"that has met fre- the fact that they are microfossils that haye quently and infomally thougl the last 20 only lately come to be important as strati- years to share infomation about conodonts, graphic tools, or from the fact that nothing argueconclusions, and correct the misappre- quite like them exists today, so their zoologic hensionsof its seniormembers. relations axeuncertain. Karen Tyler, faculty illustrator at The Ohio In this monograph, I provide a summary of State University, drafted nea y all the figures information about a group with which I have from my very crude copy and assistedwith la- worked all my adult life. Charts that name con- beling others. Dr. Jerzy Dzik, of the Polish odont-based biozones and show stratigraphic Acaderny of Sciences, Warszawa, provided rangeofselected conodont speciesare included about half the stippled drawings of conodonts as Appendix B. However, I have purposely that gace various figuresin Chapter 5- The an- avoided a recap of conodont biostratigtaphy istry of tlrese two good friends is plainly evi- becauseit is constantly changing and cunent dent in their work and is warmlY views are readily available in various other acknowledged. places.Instead, I focus here on the conodonts I am also grateful to Sue Shipley and David as a group of extinct animals, about which it is Little, of The Ohio State University, for their important to know as much as possible be- help in completing various parts of the manu- fore assessing their distribution biostrati- script and illustrations, and to Mark Klefner, graphically. who graciously cornpiled information on the Of course, one takes considerablerisk in at- ranges of Silurian conodonts and assembled tempting such a summary, particularly of a the Silurian chart in Appendix B. The Depart- group of animals known only from its fossil re- ment of Geology and Mineralology generously cord, becausemost of what I think I know assumedmuch of the expenseof drafting and about conodontsas animals is either conjecture photogaphy. or a highly personalinterpretation ofa still-irn- perfect fossil record. So, with the caveal that Columbus, Ohio w.c.s. whal followsis only one way of viewingan im- February 1988 CONTENTS l. Inhoduction

l.l History ofdiscovery and study 3 1.2 Achievements 7 1.3 Pending problems 8

2. Skeletal anatomy 11

2.1 Composition of conodont elements ll 2.2 Structure of skeletalelements t2 2.3 Shapesof element crowns t4 2.3.1 Coniform crowns l5 2.3.2 Ramiform crowns t6 2.3.3 Rastratecrowns l8 2.3.4 Pectiniformcrowns t9 2.4 Symmetry- and curvature-transitionseries 22 2.5 Skeletalapparatuses 2.6 Symmetry of elements,element pairs, and apparatuses 25

J. Whole-animal anatomy 28

3.1 The Scottish Carboniferousspecimens 28 3.2 The Waukeshaspecimen 3Z 3.3 Histology of demineralizedtissues 33 3.4 Summary JJ

4. Taxonomy 35

4.1 Form taxonomy J) 4.2 Multielementtaxonomy 36 4.2.1 Multielementmethodology 4-3 Multielement classifications 4l 4.4 A revised multielement classification 41

5. The major conodontgroups 45

5.1 Introduction 45 5.2 Cavidonti and Conodonti 45 5.3 The Proconodontida (Cavidonti) and its families (Fig. 5.1) 45 5.4 The Belodellida and its families (Fig. 5.1) 49 5.5 OrderProtopanderodontida, new 5l 5.5.1 Family ProtopanderodontidaeLindstrtim, 1970 52 5.5.2 Family ClavohamulidaeLindstrdm, 1970 53 5.5.3 Family AcanthodontidaeLindstritm, 1970 54 5.5.4 Family DrepanoistodontidaeFihraeus and Nowlan, 1978 54 t vtl III eIc,(Ju?rrr^opro ele-I pue opprw z.€.9 B €€l II pue I selci(c I'9 9 B €[l selc,brsplo-puoces t.g ) r'8 ztr selc^crurel-?uo'I Z'2 9 t ztr uroll?dIpre^O lZ'9 I 0€r surened./hrsJe^r( Z'g I 6ZI uorpnporlul I'9 ) €'8 s z'8 6Zl suraDEd.tftuopnlo^fi v r'8 'lqeN pu? uosuerge"p4uopoeloJ qal oql '8 tzr ??6I I.0l.s tzr u,l^Irrrrs{ ou)lun JspJO 0I'S zzl 196l 'sapoqupue u4snv a?pqleuaolse^flurq €1.6.s 'sepoqupu? u48nv e"pqleuEsn^?Jr{lrureJ L 0zl I86I zl.6.s 'reulu e"pqleuEolee^\s,{Iulec L Ltl 9g6l I I.6's SII 'IJelJ eap4uopoqpuftqruvi(Iu"c {. 9'L 7,L61 01.6.s €II 'quoiasauuloHpu? srxeH eeprluopoql"u8orpl L e€6I 6.6's III snqQuSpSoApue DaUqroT^lrtued g'6 L S ll\au.eep4uopoqleuc dlrued L 60r L.6.s 'sepoqupu? urlsnv eepqleuSolcrla L 90r Ig6I 9.6.9 ,reu.e?prdelolerul?d^lluleg^lrued I SL z0l 5.6.5 .relssegesprqlsuai(lod flruleg L 66 sz6l ,.6.s 'redooJeup4uopornBdsoreld ]{lrurEJ L 86 LL6l E 6.s Ltt 'reddelxeeprTlele{co) {[u]BJ L Ig6I 2.6.5 s ?'r 06 6S6l 'sseHe"p4uopoqleu8oqteds I.6.s 68 'Irzq ?prurpolrBzo^IruBJ eqJ L 916l 6's L8 'uro.4spurla?prTlelopuoc /(Iuleg L 016I s.g.s g tL s8 zL6l'TrelJeuprruoslllg/([rrrEg t.g.s .ur-o.4spur.Ie"pr-rlleuEorlceg I zL €8 016l r{lrureJ €.9.s I8 :relssege"puporuogd /{lrluec q IL 9Z6l z.g.s OL tt6l 'Iqew pue uosu?rge?prqleutorqc {IIu"c I.g's FOslEd '' 8L ,{\ou'eprurporuoFd aql g s 9L 016I'ruo4spur-IsBprluopouod,(lruJel zI. L's SL 016I 'urgrtspur.I*pqtsuEoprdrqu ll' L.s s 8'9 NL 6S6l 'ss?Hosprluoporuo!^J ,tllru?{^lrru?d 0I.L.s 9 ct ,r\eu'eeprurpopald ,qFued 6'L'g 9 ZL tg6l 'slrrsH e"p4uopolsro4lnll g.t.s rruorlstrege"pql"utoceld^lod^llure{ x L9 IL Ig6l ^Irue{ L.L-9 9 69 ts6l 'rellnn pu? relml I e?pnuopoucl.,(Iuleg g L.s 9 /o Ig6I 'redd"Dl eepquopouolsr(IJ{lruleg S-L-S 9 s9 1l\eu'eepqlepoucl/(IIuIug v'L's f. 9'9 t9 6S6l 'sseHe"pqleuEopg ,{IurBJ E L.s rI s'9 z9 9z6l 'r3lss?ge?pquoporuoud {lrrrrBJ z.L's a v9 09 016l 'ur-o.4spur.Ie"puuopolsro lL.s 9 6S 9L6I'I:IZ(, sprluoporuoud^lruru eqJ ,'s r 9 9S 0t6I'rrrojtspur.I e?prluopolepued^lrruBJ I.9.S v 9 ss spquoporepuedeql 9'9 hl SJNAINOC IITA

L \,,, CONTENTS lx

55 6.3.3 Siluriancycles r34 fb 6.3.4 Devonian and Carboniferouscycles 135 59 6.3.5 Permian and Triassic cycles r37 60 6.4 Extinction 138 62 6.5 Iterativeevolutionarypatterns 140 63 6.6 Evolutionary trends t42 65 6.6.1 Apparatuselaboration t42 67 6.6.2 Apparatusreduction 143 69 6.6.3 Elaboration of elementsin P positions 144 7l 6.7 Developmentalslralegies 145 72 6.7.1 Recapitulation 145 6.7.2 Paedomorphosrs t46 74 6.8 Summary t46 75 76 78 7. Paleoecologyand paleobiogeography 149 79 8l 7.1 Introduction 149 83 7.2 Mode of life, or habit, of conodonts 149 7.3 Ecologicmodels 6) 150 87 1.3.1 Thedepth-stratificationmodel l5l 89 1.3.2 The lateral-segegationmodel 152 90 7.4 Selectedstudies of conodont ecology 152 9'7 7.4.1 Ordovician paleoecologyof Cincinnati Region t52 98 7.4.2 Mississippianpaleoecology, western United States 157 99 7.4.3 Paleoecologyof Pennsylvanianconodonts 160 t02 7.5 Ecologicgeneralizations 164 r06 7.5.1 Depth as a factor 165 109 7.5.2 Ternperutureas a factor 165 tlt 7.5.3 Nearshoreand ofshore faunas 165 7.5.4 Phyletic changesin ecologicaldistribution l_ - ::l 113 t66 115 7.6 Paleobiogeography 166 |7 7.6.1 Late Cambrian and Ordovician paleobiogeography t67 t20 7.6.2 l-ater Paleozoicand Triassic paleobiogeography 167 122 123 8, The phylum Conodonta 170 t23 8.1 A personalbias 170 t29 8.2 Summary of conodont characters 170 8.3 Conodonts as invertebrates t7l r29 8.3.1 Arthropod and annelid connections t7l r30 8.3.2 Molluscanconnections 172 132 8.3.3 Connectionswith other invertebrates 173 132 8.4 Conodonts as chordates 175 133 8.4.1 The opinions of Pander 175 133 8.4.2 Newberry, Hinde, Huxley and Myxine r75 t34 8.4.3 Macfarlane and the nemertineanconnection 176 s07 XAPUI 68r sueqc e?uerrrqder8uats g xrpuaddv s8l etuopouoJ eql Jo uo4?cgrsselctuputuns v v xpuoddv

z8l ro^ug..I g.g I8I seuru{geol?pJoqc ?urlecrpur sernlee3 Jo fu?ruruns 6.t.g 6LI auxftl,tJ1o snteredd?pnAuq eqJ g.r.g suourceds LLI snolgJruoqJ?Jqsr ors eqlJo suorlelsrfualuy 4.7.g LLI slualuoleJo qyro:8 pue uoqrsodruoJ 9.t.9 9LI IBllaletu ,{uoq pseq Jo uorl"laJfuelur pue fus^ocsrq S.r'g 9LI relsssgpu? qslrlnJoJerTeq eqL n.v.g troJ eqJ SJ-NETNOi) The Conodonta 176 t76 t77 t77 t79 181 t82

185 189 lu) sr Jl ? -ro j I SUOIlqer ,i(qroN h or e,ia ',(e^rnslmrEoloaC srourlll ,{q peqsruJnJ,tlpuDl se^ntsod -EIp Jolo3 uro+ apeIII quud 'snpoqwug ^oupoU P SJTUEe_I elrq^\ pue \Jelg Jo seroads_ed^lpel?u8rsap ,{lluacor s?^{ rr qcrgA '(,(punou) snpaultrq snpoqpug slueseJderpue eueluol uI $lcoJ snoJeJruoqffCrando-I t FxuJs .srourll I , il sruoq uro{ sr e8elqueswurouog ur $IcoJ(u"unossrl I) ueru?Al^suusdruo{ ,(sepoql{)snrld,t mqpuSo .gtx ,slueuale |$O-XJ Jq us Jo ed,tloloqsr dol tp atelqruassv luopouocJosaEelqruesie prnlep F suopo r {qr uI 'tuJsard + m uJrq F J{OZOel lfuL\los le lxxroJ Jql q leql lnq cfed srql D :{IO lsEAI lE-fueduroJ slrsso_I qer naql :qr:roru b ;mssed ?rI _to fg G rGololq hs Eruoq |D 'ulued r|e F:ujeal ppol-t ou1 r -iqdB-6'u Fdar rsot! &1u.uo5 x sdno-6 IP|:-j llJto lEseq lual lsqf, ale.$ t D Jrqde6 3122\ $.el e lEi sFsso_I FB PaESU lsso_loDlur lla-rur luJn FisE lsour P IJOJ Juu r ls.n! Fl.\\

?J 'I I.L\I tt 4! 1. INTRODUCTION

With just a bit of preparation,almost any ma- opment. The literature on conodontsis now rine rock of Paleozoicor Triassicage, from al- rather large(and growingat the rate of about most anywhereon earth,will yield to the pa- 300new paperseach year), so it will not be pos- tient investigatoran assortmentof phosphatic sibleto exploreevery aspect ofconodont paleo- microfossils termed conodonts. Although biology in great depth. But this book is not named and first describedin 1856,these tiny intended as a comprehensivereview for spe- fossilswere paleontologiccuriosities until just ciatists.It is an attempt to summarizecurrent a few yearsago. Little wasknown of their geo- knowledgeof conodontsfor the nonspecialist, graphicor stratigraphicdistribution, and they who may well have been wonderingwhy this were classifiedaccording to a mechanicalsys- group of tiny fossilshas come to be so impor- tem based entirely on shape. Furthermore, tant rn recent years. their relations to other, better-knownanimal groupswere hotly debated. 1.1 Historyof Discov€ryand Study Nowadays, conodonts are mentioned in most reportson Paleozoicand Triassicbiostra- Sometimebetween 1833 and 1844,the Russian tigaphy, and their contribution is widely ac- paleontologistChristian Heinrich Panderdis- knowtedged.Furthermore, enough has been covered tiny, lustrous, toothlike fossils in learnedabout their anatomy,associations, and washedresidues of Lower Ordovician and Si- patterns of developmentto make them the lurian clastic rocks from Estonia,and on the honestsubjects ofa wide variety oftruly paleo- surfaceof at least one slab of Carboniferous biologicstudies; Thirty yearsago only a hand- rock collectedwithin the presentcity limits of ful of paleontologistsclaimed more than a Moscow. However, these microscopicfossils passingacquaintance with conodonts.Today, werenot illustratedor discussedin print until more than 200 personsdevote a major part of 1856,when they weredescribed as the remains their waking hours to the study of thesetiny of an otherwiseunknown group of Paleozoic fossils,and only a few of the world's major oil fishesthat Pander named Conodonten(con- companiesor geologicsurveys are without at odontsin English). least one conodontspecialist. The reasonsfor In the yearsbetween 1833 and 1856,Pander this paleontologicsuccess story are numerous, evidently gave a lot of thought to the tiny fos- but they have to do primarily with the fact that sils he named conodonts.During part of that the conodontshave proved to be as successful time, he hadgeat troublewith his eyesand was at solvingbiostratigraphic problems in the Pa- not ableto usehis microscope.However, what leozoic and Triassic as the foraminifershave he sawwhen he wasable to studyhis specimens been in the interval from the Jurassicto the microscopicallyconvinced him that he was present. looking at the teeth and jaws of a previously In this monographI will introducethe con- unknowngroup offishes, a groupwith no rnod- odonts;show how at least someof them may em analogue.Thus, in descriptionsof speci- jumbled f*:-c -gntrrus be reconstructedfrom the bags of mensin his collectionhe usedterminology ap- jaws Ebiage is from bones by which they are commonly repre- propriate to the teeth and of fishes, and survives today. @; r- u'hich sentedin the fossil record;and look at major some of that terminology provided b trc :ulor dia- features of their long geologic history, with an Pander's1856 monograph not only eye to suggestingsomelhing useful about their the first descriptions of the hard parts of a pre- relationsto other animalsand about their pat- viously unknowngroup of animalsand a name tems of deploymentand evolutionary devel- for the group itself, but it also began debates -rIULl:OlT1 -uo3 e,{1pu? .seqsge^4lrrrJd Jo qleel se ueql sluopouoc eluos ls?sl lE l?ql eepr eql psJo^ Fr :rqr.rad Pass?pe^?q sluopouoc sluopnlsluecel .,, Jo ll? --?JopulH :edeqs eru?s eql e are^\ lEql sued ItE 5JEE i .tlrzau tErI eloJ r pue uosuelg ..ra? 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VJ-NOOONOJ AHl- INTRODUCTION

J sr eral different cur in that classification."They regardedthe In 1941, Samuel Ellison, a student of the rL< out to have evidencefor this statement,and for their fur- Missouri school,and Roy Graves,one of his rSme today agrees ther conyiction that conodontsare polyphy- students at the Missouri School of Mines, h :ased his con- letic, as conclusive,but they put off describing jointly reportedon a group of Pennsylvanian qrs.nrs bits and that evidenceuntil a latertime. Unfortunately, conodont elementsthey had collected from tra Jilferent spe- that time never came. However, they did al- samplesof the Dimple Limestonein Texas, ! r!g:L bur for the lude to the fact that their evid€nceof the fish which they had dissolvedin dilute aceticacid. natureofconodonts is the fact that somespec- Ellisonand Gravesdo not describethe "acetic h:.-iogists E. O. imensare attached to a substance". . . that ap- acid method" they used, which suggeststhat trnaal manv new pearsbony but doesnot have the structureof they did not regardit as novel. However,they h.= presented a ordinarybone." were evidently the frrst to use a laboratory pro- r- .::d suggested Bransonand Mehl also joined Pander,Ul- cedurethat, a decadelater, had becomeroutine bn-.:g:r be of con- rich and Bassler,and all previous studentsof in researchinstitutions around the world. The d[i< rtre srratig- conodontsexcept Hinde in usingthe shapeof significanceofthis is that prior to 1941,and for rrs s.rch as the individual "teeth" as the guide to their classi about a decadeafter, most collectionsof con- he-.:rcga Shale. fication. That is, like their predecessors,they odont elements had been assembledfrom i rhat con- adoptedform taxonomy. However, like Ulrich shalesand other readily disaggregatedrocks, l' --:.-il::s of prim- and Bassler,they thought it likety that speci and carbonaterocks were generallyignored. ,d[ :l lhe same mens of different shapefunctioned in diferent However,as Ellison and Gravesdemonstrated ,-- =E: rhe preva- ways-some as teeth and jaws, othersas body in 1941,as Branson and Mehl reportedin 1944, t :i :lese teeth scales,and additional ones as denticles on and as nearly everyoneknows today, much I cr :ires in the sprnes. largercollections of well-preservedspecimens bv the Between1933 and 1950,the Missouri school can be isolatedreadily from carbonatesby dis- --::d rmly on flourishedunder the leadershipofBranson and solvingthem slowly in l0 to 15 percentacetic b-E: mt:--r of zool- Mehl, and the predictionof Ulrich and Bassler or formic acid.This, in turn, meansthat, unlike k ltaving Ul- that conodontsmight one day be of greatuse many other types of microfossils,conodonts --a :-rib$antial stratigraphicallyencouraged other American may be collectedeasily and relativelyinexpen- - studentsto collect and describethese previ sively from both carbonateand siliciclastic f Bassler wrote ously enigmaticfossils. As a consequence,the rocks.Thus their distribution in stratigaphic ta= ir is clear literatureon conodonts-a mere200 articles in sectionsof mixed lithologictype may be deter- |!c :afer -\meri- the late 1920s-more than tripled between mined wilh considerableprecision. ql --:e srud] of 1930and 1950.It is not easyto singleout any The increasedsize of collectionsmade pos- lE:Jnrial were of theseconributions as more important than sibleby more widespreaduse of organicacids l*itr:ologrsts at the others,but it is not diftcult to identifythose encouragedmicropaleontologists interested in b= g- 6on.on that introducedsignificant new trends. conodonts to broaden their studies through ll:,;. -: Studies, In 1934,for example,Hermann Schmidtin considerationof sectionsin which there were lllcl-:\hed b-y the Germany and Harold Scott in the United no shales or mechanicallyreducible clastic i ::ll and 1934, Statesindependently reported the discoveryof rocks.By 1959,conodonts had beencollected tirr s:.d;- of con- clustersof morphologicaltydifferent conodont in some variety from rocks that rangein age r making elements on the surfacesof Carboniferous from Late Cambrian to late Triassic, and there -+:hit: rcpresen- black shale stabs.Like Hinde before them, was one report of distinctive elementsfrom G qosn than Schmidt and Scott regarded these natural as- Upper Cretaceousrocks in west Africa. Fur- l* a semblagesas the more or lesscomplete appa- thermore,conodonts were known from marine rc:e -oducedand deal ratusesof individualconodonts-an opinion rocksin this time interval from six ofthe seyen r:r:: group of that wasroundly criticizedby Bransonand ev- continents. The stratigraphicrange of con- idently acceptedwith great reservationsby odonts had been considerably broadened J C:.,:itnt Stud- other studentsof conodonts.In more recent through improvements in laboratory tech- : lftir: --. . nearly yearsnatural assemblageshave playedan im- niques,and geographicdistribution had been G classed portant role in the developmentof conodont extendedand collectionsgreatly increasedin k- -re *e con- taxonomy. size.No longerwere inyestigators satisfied with -i Er pJr{srlqnd -Inos qJnru JaUe papnlJuoc ,,tueu ,AJnq eC -oss? lueunrer peuuoJ u penulluoc l?qt sed,q cfoloqdJou -JetrAIUr Sra{lo,{\ luopouocJo ecuJeJuoc esJe,l.rp Jpuoll Jo sluetuela Jo sdnoJt olul ,tlpu:a1ut lbq sau1o11 -Erlolur ue uI .os Jo sJ?e,{g I46I ur sluopouoJ popr^rp 3q plnos soorlcsuoJ esoql palou r pJlqruess? ur ,{luouox?l lEql uuoJ oc?ldeJ plno,| souolejoqq pJe^es .paqsrurul loqB eJnl?le ul sJol?B4se^ur lueuralenlnu leql ,{Duapguoc pu?^urouox?l ,(lcuqnd -Ip ueqt uoe^rtreq 3qderSoltqrq sdBBcrqdel8rteJls se pue ezrs peplperd I pue ulorlsEreg BnS ut 6961 ul sluJujelJ alJlJstp suorlJJJloJSV q uJJq e^eq ',{lJE3luouox?1 ^^eJ8 Jo tlleql elen 'lpo8alqput?upun rE[u pFoqs pue e sEuJes sB^l 1B^a sdnolt luaunoeJ ,{34uapro1 ,{1a,rr1ce3'elqellns arour ^lleJ[JEld uI PIa sp pepl?Aej q8nogl I 0s6l -Jeposn eq tq8lru senbrurlJolAuuetsnJcJo sed^l ^ll?cltolorq Suluos uI 1€'seEeTqluassEI"Jnleu lo,slueuelaJo sJelsnJc uo pessq .setseds 'edoJng e loqs uI luopo -uooJo lrupu?q^urouoxel e uegl eJorx srsouEetp I{01 -E le Jo el?ud -oJddBUoddns ol se8?Jqruoss? rl3lu {lsrJos IeJnteu pug le^e plno.r J^i l?ql lqnop Burss:ldxa,{qfutouoxEl $Jo serqdH rrroJ esn ponu4uoc sJe{ro^{ Jo ezrl?uorl?J ol elqrssod P{re IPJrlsqels q8no:oq1 e ol pelJefqns ele^\ sdnoJt se,'All 'clqd?JEp?Jtsorq s?.r stuopo JO Sarll^rpe luerrncoJ upnl^opro eql .,4Eolourr.uJol 6961 uI -uoc uI tssJelur se Buo[ s?^lu?uud pue ,{lJ?rrqda8rleJts FrJllelSAeU e^nduJsep SursnJuoJ etuos puE seru,(uoufs perEds qarJossv .Euol flepl^l pue IIEurs aJe^l suorpoJlo3 se lec xJldrloJ ur pJllnsJr,{riq^ .a.rntelrueu .s0S6l Auo[ se're^a^{oH aW ,(q.{ruouox?l 0 sluopouos -oN IeJTSOIoOZJo selnu eql qlp\ ecu?procc? rrrroJ uerJepu?d ^lree req seq :0SZ Jo /benbep?ur Iml8olorq aql poolsJepun sluopnls ffi s?q ,{larJ snoues JJelEgl Aurcur^uo3 os ere^{ 'ZS6T ur sepoqu fq {pn1s rnsar luopo luz8ele ue qlr/h pJIdnoJ.lloJs pue lprrrJqJs,{qsreded FJo asotund oqt 1€gl pedsns .sluopouo. t|s3JelureUO I Jo sluepnts luonbes -qns IIlo{J sesuod$r e^q?Beu ,{leAlBI pelo^ord lorlezIuESro luJoJ ol peua^eJ JesrlJ?A\.seroads luopouo, e6 e,\?q 01 Jo poJouAr ugeq e Eq elqord oseql -urs ol suaes )[]o.r\ Jo sasnlpnddE lelelels eql se pepl?8 s,apurH q8noqtlv n-6 SurseeJc lroi Jo u?ruo^e(l eql -er sdno:3 luorrn3eJ Jo lequnu^le)trt B suorlcelloc ruo{ ^{eN relsnlc peunsejd ? 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IIJJ?eserluopouoc suoq"punoJeql walJ zlqe etlles eql uI sdnoJA Jo luernceJ rrrJoJslueuale Iooqs leql sFsodord01s0g6l orsJe^ pesl^ eleJisrpJo alpprulaql ur pol suorlJolloour sueurceds qcrq^\ euTrrr uJecuocsrqJ .eseq qJnu Jruouox?l eqlJo 1I5 slr -rJtep lqSrur Juo rlJrrl,r EuJluJ .s096I Jql pelsrl lnoq? ureruo3 prp os ,{lr?epu? ^lrTrqElrns s0s6l r E aru aJeql rasrll?A\ 'uo4lppE .usunJrs^q uI eql ruo{ suo4 aql q8norql suorlJJlloJ pJllofluoJ_ll:^\ l iruouoxel -celJocsrl ur suorlsrJoss€qrns euru pequssep ^\JA.atreJ s pesou8Erp .$ICol .;o raqrunu aq1 sy resr[eiA tg6T uI JrssEUI ruo{ slueurela ^ll?Jlqda8lleJls EU JO eCUeS alaJcsrpJosuoncelloc ur sdnoj8 lueunceJ qcns Jlqde$p'Jls snoJor[nu*"r, r PUEsluop laJ^es pegrlueprJpeu{JnH .:lourexo .3g61 :oj lE ue{el ssldu"s Jear"lqcnu uo pelsrs Fnssp sroru uJ sle^Jolur cqdeJAn?Jls ^lasolc "n^r"rr:;:l;;: erlles eq1 uI soldu?s -ur lsohl 'selBqsJoBurqse,n snouoq?1 ,{q pal?la p 8u[lcJees e^rsseo3nsur ecua?oddeeJ q8noJqi suortprc -qrJsueurcadsJo srsqurnu reEeeur ,{lereue8 eql tt VJNOCONOJ gHJ w 7 INTRODUCTION

G : :uccessive searchingthat multielement taxonomy was lison have continued with the published bibli- ItL: ::::1a15. In more desirablethan form taxonomyfor cono- ographies of the conodont literature that are lr-a:-t3J several donts and was also attainableeven in the ab- listed among the referencesat the end of this ER:-:adiscrete senceof natural assemblagesto supportevery chapter. In more recent years, the bibliography , h ::-: \\ alliser diagnosedspecies. A complete multielement of conodont literature has been updated an- ms - rS !'ollec- taxonomy is still not in place,however, and nually in a supplement to The Pander Society's ril--: \\'alliser thereare a number of workerswho still prefer newsletter. At the end of 1987,my file included uE -: _.:i: deter- its much simpler predecessor.However, a re- the titles of more than 7000 books, articles, and k*- -:. :: ii:crete vised versionof Volume W of the now-vener- papers on conodonts. 4-'- -: --:lesame able Treatise on Inwrtebrate Paleontology Er: :-. :-,idence (Clark et al., l98l) issuedin 1981(but written 1.2 Achievements a r r-: :t useful largelybefore 1976) is couchedmostly in terms E:-: of multielementtaxonomy, and a majority of The study olconodonts is very different in the FrE- '-::: -aaulTent:One of current reportson conodontsat leastgive lip 1980sfrom what it was in 1950,when I began. G: : :Jiually service to this more sophisticatedmode of For example, in the last 30 years interest in - E :'- . oirhe classification. conodonts has again become international, For . .: them In 1967students of conodontsattending an much of the time between 1926 and 1950, --:: I-: . -::matic internationalsymposium on the DevonianSys- study of conodonts was largely an American &ts: tem in Calgary,Alberta, were impressedwith endeavor; now there is active and increasingly l{tl * .:r:s and the fact that data provided by conodontscon- well-informed interest in nearly every part of d :.:: : -,q into tributed to a very largenumber of the reports the globe. At a meeting of The Pander Society { I -:i.tede. presentedand with the difficulty they experi- in 1985, the approximately 150 participants - lt ,",r. ,': had encedin keepingabreast ofthe burgeoninglit- represented 31 different countries in Africa, fu- -:: , latan eratureand researchinterests of a rapidly in- Asia, Australia, Europe, and North and South TE1 =, _f s re- creasinggroup of conodontstudents. To solve America. Study has become international I!Er-: - _i.- t: stn- theseproblems, the groupfounded an informal again, and there is also close coordination and flF :--:::':Ofm organization,The Pander Sociery, open to any- an unusual degree of cooperation among stu- F'-- t-: Ber_s- oneinterested in conodontsand with the single dents of conodonts. These achievements, per- --: Gr- \': :.::-toses purposeofsharing information on currentcon- haps more than any others, have enabled the E-f,::: :-: -:r5 In odont research.Subsequently, The PanderSo- rapid growth ofknowledge about conodonts in fte ::": ,jiag- ciety has grown in membershipto more than recent decades. I :: ia: -: stnct 250;has becomethe official working group on As noted earlier, assessmentof large, strati- f i.:,- 1e- graphically - -;31 conodontsof the International Palaeontologi- comprehensive collections on an : _lin plex cal Association:and has distributedan annual intemational scale has also caused a shift in -i E[T_::5a::plrve newsletterthat includesreports on the research taxonomic base from the morphology of single F:L--r- ti-_drlent activities of members,addresses of conodont skeletal elemenls to the composition and rela- !: ,ri-: !-rslical workersand, in recentyears, current bibliog- tionships within recurrent groups of skeletal G5- -- :'::ngth- raphiesofthe conodontliterature. The Pander elements. This has resulted in a taxonomy for E :---:-:l lnter- Societymeets annually in North America and conodonts that, while admittedly more com- EE_--{ t: single at 3- to s-year intervals at various sites in plex than its predecessor,is probably closer to lTl --:':-::Lr ely. Europe. biologic "truth" than the form taxonomy of ka-_': -_--:: olher In sortingout significantevents of the post- Pander, Ulrich and Bassler, and Branson and GE: r t.: -lsed ef- 1950era in the history of conodontresearch, I Mehl. Such a taxonomy is obviously a collec- *::Ceval- 3:: - should mention that students of conodonts tive effort and, like any other, will always be have been blessedmore or lessregularly with ripe for modification and the subject for de- D: - :3dicted bibliographers,who have kept track of the lit- bate. Nevertheless, students ofconodonts now f - - --:3lement eratureabout conodontsand haveperiodically have the framework within which to make _:- fi : t!\m) rn assembledand published lists of it. Grace biologically meaningful statements about con- [:- paleoecology, ": -rterna- Holmesbegan this servicein 1928;Robert Fay odont biogeography, and evolu- :r.-.,:t! .n \[ar- continuedit through 1948,with a usefulcatalog lion. and that musl be regardedas an impor- 6c: :- -:: soul- publishedin 1952;and Sidneyesh and SamEl- tant achievement. g JlEalbeps srql 're^e^1.oH'cruoDlsu ]{llsour ,(JqsqoJdsnql pepnJcur e^eq ol s(IIees t?ql {urul € :stueut r puE 'uraql puP slrqou ele^{ slEulrue eql l?ql uorlseS:ins -ole luopouooJo o8elquasse IeJnlBu e sur?luoJ ur aJu3pr^e requnJ e sr suerurssdsqsr1lo3s alalduoc ssello leql p?oq snoqlnq 3 rIlL{ elnl"erc elllllllo,r I ,oslv .31331 TJtelduroJ erour eql Jo uu Tr4 lueuruord eql 'eletuole ue ueeq e^?g ol sorceds uErlu?ur(I | ?lns eq oI .sluopouoo -ed s?^r eJrlJo epotu tuEururop eql l?qt uoq?c eql slrssoJ oseqJ Aoldruoc frI.iqd puE ^loqs -rpur uB s? sarJ"Jel?qs-Icelq aql uI sluopouoJ sselJo eJoruluoseJdal ol uees lBql suau Itr qJrq^\ le gnuuuoc JO eCUe nCCOUOUTIuOC eql pJ?EOJol -neds IsJe os Jo pu?llocs ur s{col^loJns uErlu?ur(I ilsurl I prmar puonnqulsrp Oqt Jo selnlseJ uro{ ul (9861 'qt$rs pue 'uos{rBIC ,s8itug .e8pu ql pusrullIo eJrl Jo epour Eururu.uatepJo su?e(Il urelJ'x 2 -ptv :€86I'e8plrplv pu?,uos{r?lJ,s8itug) qu pellelep pesodord se seq Juo pu? .(+rlJo la,{ ou sJporx ,fue^oJsrp lueceJ eql lsll plnoqs I F Ur SaSUd eseql Jo q3?e luaseJdeJ euJosJr lo) sJa sJ?e,{0€ lsed oqlJo slueue^erqoe^lurcuoc eqt Auoluv rorpnls ^?ur luas lIo^{P uouoq Jo 'sJel?ou 'sJerurrjr^is eJo^\ i(oql 'eBu"J eJnlEledurel JepEoJq ? 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UO pup slsreoloJeJrururerogyo Auedruoc aql ol ssec bloJa luopo 'slueue^arqce luaca.ltuorue qErq -o? Eu€pnJE ureql peurE8seq leql auo oql pu" aqunJ 3^leP ,e{rd Iu?J uorlducsep pue fue^oJsrp Jreql puE 'esJnocJo 'Alauolou lsol?eJAeql peululle eAEq tJlI-Jo-0poru eql u^,\op erxoJ 0^?rl ol sluopouoc alelduloc sluopouoc Jo sluepnts qcq^\ JoJ lueure^arqcE ilale^{ eurJ JoJseleprpu€J Surcul^uoc lsou eql Jq snql oJB eql sr srqJ tuolsrq rrsseul puu orozoal?d Jo eqt ur elou Ppnu teql ot tuerclgns sr lr aroq :€ Jetd?qJ spedsE snouE^ eql Jo ses^pu? peugeJ i(ll?uon JJnlearJ ^eql Ern ur solor tuuJ?ls a^Eq III^1 suoutDeds qsnlof,s -decxa o{?u.t 01 elqrssod sr 1r qcrqa urqlr,r I e^4e[3J eqJ uU ^\ou JO I?pn€J tueuruoJd e pve :(snxotqd IJor'aorrr?JJe rrloJ gcrq^{'seuozorq 0SI lnoq? r qJlq^l llee -tttv =) ouolsotlpuotg elP.pJorli e^Brluud olur e8e crsszua q8noJqt u?uqusJ elq Jo trEOJd'e1e3 eql Jo (seuolo,(ur ro) qcolq olcsnlu eqt Jo $IJoJ ouu?ur pegllells opr^p 01 sleqd€JEneJls 5e lou luecsruruoJ eJ" lpql semleoJ pedsqs-uoJ^oqc -olq pelqsus s€q sluopouoc uonnqrJlsro ^eru Jo

VJNOCONOJ AHJ INTRODUCTION f ::a:-ninlscent may not apply to all conodonts,and the elon- References D--.:r::-5r of the gate, prominently "tailed" hagfish (or slime Aldridge, R. J., Briggs,D. E. G., Clarkson, E. N. W!::: =.; t= 1m- eel),which many hold to be the nearestliving K., and Smith, M. P. (1986).The afrnitiesof r =-.:- hn The relative of conodonts,is a largely sedentary conodonts-new evidencefrom the Carbonif- c:ia-:--i roles in creaturethat spendsmost ofits life in burrows erous of Edinburgh, Scotland. Lethqia l9(4), I L: -::: :fat they in the muddy substrateof relativelydeep ma- 219-29t. mg ;::-iates for rine water. Clearly, we need to addressthe Ash,S. R. (1961).Bibliography and indexofcon- odonts, 1949-1958. Micropaleontology 7, 213- R ::-: :-r\\n the mode-oflife question intensively before we 244. C :er: -:--on rank delve further into headysubjects such as con- Bergstrtim,S. M., and Sweet,W. C. (1966).Con- Eli. odont ecologyor biogeography. odonts from the Lexington Limestone (Middle On a more mundanelevel, but nevertheless Ordovician) of Kentucky and its lateral equiv- of signalimportance, is the businessoffilling in alents in Ohio and Indiana. Bull. Am. Paleont. s0(229),27t-44t. a number of gapsin the current stratigraphic Branson,E. B., and Mehl, M. G. (1933-1934). __- ..:3s ledge record of the Conodonta.Lower Ordovician Conodont Studies.Unlv. Missouri StudiesS.l- ill- -,r-- =ore in- speciesare well known in the high-latitude 300. I s: : .-:tber of faunascharacteristic of Europeanlocalities, but Briggs,D. E. G., Clarkson,E. N. K., and Aldridge, (1983). I[-::::,_SSSSer/- in North America there have beenonly a few R. J. The conodontanimal. Lethata16, tr =;::::s: hereI 1-14. comprehensivereports, and theseleave a num- Clark, D. L., Sweet, W. C., Bergstriim, S. M., ber of important taxonomic and phylogenetic Klapper, G., Austin, R. L., Rhodes, F. H. T., !tr,i...:..,.3mbled questionsunanswered. The Silurian is also a Miiller, K. 1., Ziegler, W., Lindstrtim, M., ts a.;:!:c devel- problem, particularlythe part of it above the Miller, J. F., and Harris, A. G. (1981).Cono- _:\onomy EI[::] Pterospathodus amorphognat hoides Zone. This donta. I\ T rcqtise on I nvertebrate Pqleontology (ed. R. A. Robison),Pt. w, Suppl.2, wl- Ej:,- r j lbr the part of the Silurian was evidently a time of W202. Geol. Soc.America and Univ. Kansas, il": .:: -: br tn a major marineregression, with widespreadshal- 202 pp. 4|:r,. = :o e\al- low-water evaporites,and con- Ellison, S. P., Jr. (1962).Annotated bibliography, -: environments, l*ul -: : ::--. mode ditions hostile to developmentof rocks from and index. of conodonts. Texas Univ. Publ. re. a: ---,.re has which conodontsmight be extractedeasily and 6210,128 pp. (1963). to annotatedbibliog- f :--- oul - Supplement in abundance.Nevertheless, a number of very raphy, and index, of conodonts. Texqs J. Sci. --:i:::]:te- ,:: IE : io sln- important eventsin the evolutionaryhistory of 15,50-67. !CL:: ::: most the Conodontatook placeduring the late Silu- -, and Graves,R. W., Jr. (1941).I-ower &u -::s may Pennsylvanian(Dimple Limestone)conodonts - rian, and we badly needwell-documented col- . .:r . ::t-::nl1 a lectionsas the basisfor frndingout what hap- of the Marathon region, Texas. Univ. Missouri School of Mines and Metallurgy Bull., Tech. pened. Taxonomy of Carboniferous and _--: ser.r4(3), l-21. . {[: ;e still Permianconodonts is in lessrobust health than Epstein, A. G., Epstein, J. B., and Harris, L. D. fil ._:: :;3stton, is that of earlierforms or that of most Triassic (1977). Conodont color alteration-An index rc-:-I:seems lineages.Only a few studieshave addressed to organic metamorphism. U. S. Geol. Surv. J +=-: l'.-:-usi\ ely multielementtaxonomy of Mississippiancon- Prof. Paper 995, 27 pp. Fay, R. O. (1952).Catalogue of conodonts. Univ. r =-;: sied rhat odontswith conviction,and a few excellentre- Kansas PqleonL Contr. (Vertebrata) Aft. 3, 206 ,tr:,:::-.in dgell- cent studiessuggest that thereare major sur- pp. !f ::a:- of lhese prises in store for anyone who undertakes Hinde, G. J. (1879).On conodontsfrom the ! r: :: lIOpOSed detailed studiesof Permian conodonts.I rec- Chazy and Cincinnati group ofthe Cambro-Si- mg ::ce of life ommendthese stratigraphic studies strongly. lurian, and from the Hamilton and Genesee- shaledivisions ofthe Devonian in Canadaand m: :ecOrd. I Finally, we have probablyreached the stage - the United Statas. QuqrL J. Geol. Soc. London E[ -,]a-:ienceOf at which monographicstudies ofthe taxonomy 35,35r-369. tc -- an rndi- and phylogenyof major lineagesare in order. Holm€s, G. B. (1928).A biblioeraphy ofthe con- tr :: r-:- gas pe- To be sure,a numberofsuch studieshave been odonts with descriptionsof early Mississippian species.Proc. U. S. Nqt. Mus.72, Art. 5,38 pp. { :: -: ::re more completed,and my debt to them is plainly in Huckriede, R. (1958).Die Conodontender Med- m.,--. e lurther -: evidencein Chapter 5. We need still more of iterranen Trias und ihr stratigraphischerWert. rF--: ::.ltrile and them, and existingcollections will probablybe Palaod. Z. 32, l4l-l'75. E - -: i:1 er this adequateas the basisfor many. Kohut, J. J. (1969). Determination, statistical J.E--,.-l:iili -_r: lc -r J.{rl ltr:c::lottI -E:O-i aq1 0 +:iculol H :: rJ!\oq Lf_, :- ki.) t R=sodIIIo-l F :'ji reql trF:: $ ?-\rl lE t, uroJl

I a -Eof ls. _:osluau | _:-l:ru:Ie.. Dr -.:uJrrrJIa \ F. -:o lmpi [r? JI{l fsn a cLriSn-IUOJ d l: \J s"q en.? IOU lu? I se _iPrlrue ? slJOPOUO-1 qi o: pa-Lre-l F [O ]d:J\: ttLiH.su:tlt iiui eql -lo [r j:Du?d q r auoPo EoL: qJrr{r\ P T=-\nrEJed xr frrPunq .rads tF snou€\ 'dd eA,l MnS -tlzris uI 'lurl/.lte,loseuurl lqnJ loag uetsDtsdlse^,'t 'seSuEu snpul-suprl qr qlEJp I Jo seuneJtuopouof, usrcnop puP e;uEu lles eqlJo sluopouoccrss"rrJ lemo.I -:!r -ro reodn pu" olpplht .l .c .sreqe^l .(016I) .J .i[ ,133^\5 lsEr slJelqo eqJ (996t) pu? uerured lsorrlroddl) '901 's9t-8t?'8 'luoalpd t sluopouoc eqlJo fq:-lo sluau -l 'Iv tlrsnJaapog saluosapuo7 .qqy .H ,ttocs ssag sdrqsuo4elorJ?cl8olooz eql (t€6t) ir\ rn u[ poo-l 'srnlrs sop ueluopouoJ (?96l) .H .o ,rcsrllBld 'dd 6 or p"uou 901 '65 ttuoJ.MoapJ sDsuox Mun ' g l uoo D Bu"queuu'snz 'sesuE) I z' l d ft,:o (luPd ulels?e Jo (u€ru"^1,{suued Jeddn) -rn ur epunC-ueluopouoJ (t€61)-"q"r69u8n-r9dt .H .lp[uqcs onolc eeu^l?qseql ur uonnqulstp luopouoJJo 't06-988 TL:OJ SUEd .d.Jelllg '92 lorluoc plueruuoJr^Uq -kL6I) H uo^ 'tuoalDd so8elqrusssB u?ruE^l^s .dd .ZI .lrv t luopouoc [D:pclq-uos e9 -uuedJouoq"cgrsselc (Z56l) .J .H .C.sopoqu nOUSt .sercads V F tr '89 Jo]d sltw lloN S'n uprddrssrs 'd.d g -srhl puE ueruo^Jc 16'Stnqslalad su!5Bal lol uBJUauvJo suondujsap 'ss!,,Ll pDlV 1tlloy sluel'ueule^noC usqcsn qll,r 'stuopouoc'slrssoJ eIrHlool eqlJo uorlpJU rop sruols^Sueqcsunlrs ,.o .g .qculn 1eq-qcsrssru sepoqcsrg -rsselcv (9z6l) s u'relss"g pue uelrssoJrop erqderSouol{ (99SI) .H .J rropuEd 'zl-62'1.^aoJ .luoal'J 'dd .)lro^ ,uopuo.J,uleprets 'utY'N 961 21td {ruouox?l luopouot ur ldecqoc -ruv'ror^eslg sluopouoJ^{eN (?961) .I^l .rugJlspur.I ,- 'a clreueBeqJ (6961) tI S 'ru-'oJts8regpue I:IIS .lqnd .rads ,t8oloa) 'zw sLz-L1z,t -Z6E 'Q)E? tuoalDd (puErpul pu€ ,^)tcnr 'fiaq_ '^run .(tf,eqxl€I f 'sosuDx unJ pu? lo(u -uex 'orqo) uor8eu qBuurJurJ eql pJequreg 'pe) Jo 4er1s -tIJn) uplsDlo{ $a./14lO JlssDltJ uercl^opJo Jaddn pu? elpprl ur sdnof luopo puD uotwDd swalqoq ,sts,{lEue ftrypunog TtldotS -uoc luaJ.rncajJo uoqeleJfuelur pue

VJNO(IONOJ :IHl- OI Pamtan and Ecrohard Kum- Ea4soi Depl.

The generic 2. SKELETALANATOMY P,v- I. Am.

L ,{ classi- wrth a and Mis- For reasonslisted towardthe end ofchapter l, maintain that conodont elements are com- Nn- Pnr. 68, it is now clear that conodonts were primarily posed of carbonate of lime. He cited this evi soft-bodied animals. Their only mineralized denceto counter conclusionsthat the little fos- cootrol parts formed a cephalic apparatus, at least silsmight representa grouprelated to annelids Group probably jaws Kansas. partly of epidermal origin, that func- or "naked mollusks," whose or radular roi m. tioned to grasp prey and aid in the intake of elementsare of purely organiccomposition. dcs Silun. food. In most, if not all, conodonts, compo- In 1926 P. v. Roundy reported that con- 41. l- nents ofthe exoskeletalapparatus were discrete odont elements ". . . appear to be a phosphatic objects that becamedissociated from others on carbonateof lime." Six years later Stauffer and df Fer Or- Minn. death of the animal. Although collectionsat Plummer asserted,without citing further evi various places in the world house several dence, that "conodont teeth are probably hundred more or lesscompletely preservedap- chieflycalcium phosphate." Branson and Mehl paratuses,discrete specimensare the ones on seem not to have worried much about the which most of our information about the Con- chemical composition of conodont elements odontais based. but, in 1944, one of their doctoral students, Pander diagnosed lhe Conodontenin ieffis Samuel Ellison, demonstrated from X-ray of the physical characters of discrete speci- analysesthat the substanc€inyolved is a mem- mens. However, everywherein his monograph ber of the apatite isomorphous group. Because except on the pagebearing the diagnosis,he re- ofthis, conodontelements are relatively heavy ferred to the "teeth," "jaws," or "rernains" of (2.84 to 3.10) and are less solublein acetic, conodonts and thus used that word both for the formic, and citric acids than the matrix of car- animals as a whole and for their hard parts. I bonate rocks enclosingthem. This is impor- am not aware that this dual usageof conodont tant. ofcourse.because it meansthat conodont has ever puzzled anyone, but tlre potential for elements may be extracted from carbonate confusionexists. In the rest of this book I will rocks by prolonged soaking in such acids-a use the word conodont only for an entire indi- capacitythat setsthem asidefrom many other vidual ofthe Conodonta.The term "conodont fossils-and they may also be separatedfrom element" (or "skeletalelement," or just plain large acid-insoluble residues by use of healry "element") will be used for discrete compo- liquids or other types of gravity separation nents of the cephalic apparatus. techniques. The most definitive, and also the most re- cent, contribution to the subject of conodont- 2.1 Compositionof ConodontElements elementcomposition is a monographby Pietz- From what appear to have been rather primi- ner et al. (1968),whose studies led them to the tive wet-chemicalanalyses, Pander concluded following formula for the mineral matter of that the skeletal elements of conodonts are conodontelements, composed entirely of calcium carbonale (rein- Ca, Naoto (POa)3.qt(COj)0.r6 Fo', (HrO)'.s5 em kohlensaurem Kalk). L few years later, however, Harley ( I 86 I ) wrote that ". . .they are They interpreted the mineral to be francolite, a composedofphosphate and carbonateof lime, carbonate apatite in which the OH and CO, the former, contrary to my expectations, the ions substitute for phosphate and do not oc- more abundant constituent." Hinde (1879), cupy lattice positions as they do in hydroxy- like mostothers, felt that mostof Harley'sspec- apatites.Traces of at least 39 other chemical imens were not conodontsand continued to elementshave been identified in various nlaces uJ u,roJc pue qta4 qsg elllun olmb leuu?ur 'pesn Jo 13rlt. e -relul ,{Foruuroc zrB 3u!ll{ lqsDq ploe lalduroJ sI ur slueluele luopouoc leql luEeur s?q srql u$o.tJ surre'J,eql gclqd{ JoJ sued lJullslp o^u pue u^{oJc ^\aJ8pu? 'sjeqlo ssoJC oJ ql/{roJ8Jo seurrl 1? ens Jo tsrsuocstuelllole luopouoc pe^Jes"rd-Il"+-._ .{I1ueJgru DSSeJepeJd -srl papunoJJns ueeq e^?q lsnru xorq ^q leq/{ -fts tsoru 'puE fueSoluo q8norql JeAlEl '8rJ ur ,{lpcq?ruute,S?rp u^\oqs oJ? seJnl;; no.{ ,{le^rs .Uoqs .^[?uJelur -serSoJdeurEJeq sluaulele uI ^lo^N IEJnpruls Jof?IAI'oJnpruls ptuolur ur JEIrrrJrs U ur eloN eeuruj?l uourppe (q1ae1ur sz) .e?ur Jo tou .lqelJeureJ eJ? lEqt el?clpur soenls Jo d ? serdnJ -urel uoElsodde ^q a,trsseccnsqtnorql ^oqt Jo leurelxe requrnu z ',{Eoloqtuoul l?uJetxe ur ,{IlBeJAfu?^ roDstuepur u^ror8 a^?q eloqz,r ,Bu11g lsnur z se luauelo eq1 stuopouoJ Jo slue{rlele plele{s oqt qAnoqllv F Ur UOr131 I?S?qOl UIAOICruo{ SnOnu4UOCeq 01 eellaur sluoualfl arntrn4s X)UIOfeJeA\ -?l roJ repro ur leqt lno peturod ssoJg (096I |?lola{s Jo z.z rPdSS elaa '/56l) ssorC,{q sJedEdJo seuos e ur ote sJee,( 'm^01{oH F 0€ lnoqe tno lq8norq sen l?rlu?tsqns sr qcrq,{r 'posrEJueaq 0A3q $[3oJ rl'z 3rcJo 'lc J srqt Jo aru?rg[Ers eql 'uortEurt?u]r 8u$olcua qcll.{r ol eJnt?ledruol eqt ol xopur up rededJo go e qlF\ 1rq lsnf suorsuaurp eeJql uI pozqe aleJnJ3e sr slueuela luopouoJ aoJc eJrlue eq um puB .8lJ " .pexg -nsh I.Z ur suorsuaullp o.r1 ur Jo roloc ern^lqoFerrreJ l?ql pors^ocsrp useq s"q 1I El 'snonunuoc lEnpr^p u,roqs sr srql et? AurTIgl?spq pu? sauoceq uoqJEc arueeJo Jreql eJoru pu? ,uollces Jo idurs u/yroJcJo eeuruEl urql ur JeJ snr{l por erour pu? peleeq oJe se,( enpE$ ue{Jsp m e ^[leorstur -pnts stuauela plele{s elelduoc eqlJo IIe uI stueuale tuopouoc tBql^eqt l3eJ eqt loJ elqrsuodsel , su^{oJJ .Burfig .lueuela l?seq tu?l sr IELr4"ur cru?Blo pouElel sql oql I/qoJJ Pelel -slseJssel egl Icq suerursedseleJJsrp lsou 1"q1 urgll^r pourEleJ sr r{crl,,rl 5lJo^reu?{ cru?EJo ouoJ lnoqe pEJ eql suleldxe srql pue ,el?J?des luotu ue urql$ eJEId lool uo4?zrpleurur teql seleJ Ja^el?qid I -ele eql Jo slueuoduoc o,'q eql ^Ip"erqJrg \ euol? -Ipur pue uoqrsodruoJ ur ctue8Jo sr elnpnJls r uoruolslP sseDleendJo ec?JJnse sr Suqlu lEspqpue uaoJJ elEcrlep sql 'sul?llIel lsogE pezrTaauruop ,zq ot Ille3s uao/{\leqoc?J[ns eqJ .u^{oJr aql Jo esoql u?ql 'elrae{ e 'prc? ouolqcoJp,{q Jo uonnlos {po,t\, ? SesnleJ?d pozrFlauru I ,tlosuepssel pu? relcql aq ol pual ur r(l^lols pe^lossrp sr lusrrreTeluopouoc ?JI Du op f,eql 8ul[g pseq aqlJo o?unxq leql ur ,{Iuer.uud JeJ 'pe^r , $[3or 'slrefqo lEql -Jrp slueuodruoJ o^r1eqJ ,(un esaqtJo sluopouocqcrq/'( ur serpoqlale^\ eql ur suo4rp ur aJe ,(eql suo4cos urll ur pepo^oJ selnl?eJ uo luoruruoc -uocSurleJfu alur ur aJupogru8rselq"Joprsuoc Jo nul ,tnqAIIs ,Jepued ot lsrg eql osl? s?^r oq^l su^\oJ3 eq ol oruoo,{lot?T e^"q (urnnu^poou''A e) eseql |Jeds .tu?ur JoJ pelou ^q ,,{geu tr?J ?-pet?urur?l ere qloq Jo euos pu? 'stuopouocJo sljed pffq eql ur dsns I serc Elolor{diorII llrd ll::q *lsso.erJo seuozopr^r,{q perepioq sr qJrg r pseq e s"q (g) ur I uorlerlroJ '...-. -:ta1t-"_T euo oqlJo teql seereq^\ lr^ecles€qlEcruorEseq(v)urlueruoloaqt3ouno:csq1:ubipesssbrc,rrslue*elal,ropouoceleia-ruo3..1.7,aig^ult Jo (,{loJnue P luopouoc tuItU ps?q [r ur luSrc B puE Joou raqlo q1L& puoJ lsout $snlel?dd3 rrolEpeJd3 !p r(q ro eJn qr Jo ,{€cep stuopouoJ slu:tIIela :q ot ueql u?d se 'qsg F lBql snql

VJNOOONOS AHJ, ZT SKILETAL ANATOMY

thus that the Conodonta were probably not however,only the first few lamellaeoverlapped many othershave thought basally to form a very tiny basal cavity, t:: fish, as Panderand them to be. whereaslater lamellae became progressively Elementsof the cephalicapparatus of most shorter than their predecessorsas the crown conodonts were dissociatedupon death by grew larger.Basal cavities of crownswith fea- decayof the tissuesthat held them togetherin tures like this are termed basalpils, and the re- tife or by digestionofthose tissuesin the gut of mainderofthe attachmentsurface is described a predator.In only a few caseshave complete as a zoneof recessivebasal margin. apparatusesbeen preserved. After dissociation In most parts of the crowns of typical con- most conodont elementswere moved about odont elements,lamellae are 0.2 to 1.2 pm with other sedimentaryparticles on the sea- thick. However,at placesof acceleratedgrowth floor and that agitation was apparentlysuffi- in elementsthat grewlaterally to form platelike cient in most casesto separatecrowns from structures,or toward the extremitiesof those basalfillings. In any eyent,most collectionsof that built elongatecomblike shapes,lamellae conodontelements consist entirely (or almost may be as much as 5 pm thick. As noted pre- entirely)ofcrowns, and we havelittle or no in- viously, each lamella of a completeelement E1jJL :as ca\ ity, formation on the internal structureor extemal surroundsall its predecessors.We cansee edges !b*r --'1=rn- morphologyof the basalfillings for most spe- of lamellaealong the attachmentsurfaces of cies.I suspectthat th€ basalfillings of a great crowns-however. and outlinesof someofthem r a--- :ored for many species,perhaps the majority, wereonly are cornmonly visible in transmitted light t& --:e trrst to slightly mineralized-or not mineralized al all. within the thinner partsof many crowns.Each I n --::: sections They aremostly unknown as isolated objects in lamellais built on a frameworkof organicma- rom:: dif- rocksthat contain lots of discretecrowns, and terial, and the tiny apatitecrystallites that mi {me =wI-nr frlling they do not occur in any of the completeap- neralizethis frameworkare orientedwith their E". :-

VINOOONOS AHI nl SKELETAL ANATOMY t) ta:: io leaye the TABLE 2.1. Shapecategories ofconodonl elemenls r;:::-:ol ofthe tis- Primary E- iil short, the Major shapecategory divisions Secondarydivisions -Gli''-ti masses ln Coniform (simple cones) Geniculate F--i :nd lhe se- Nongeniculale 6 :;: :-- ontogenet- Ramiform (bars) Alate e ...::essionsof Teniopedate 's-,:-?nt tn tax- Digyrate Breviform Extensiform lz;--- of rhe life Bipennate Dolabrate E-:: ro the fact Quadriramate Multiramate qnl-: -_:o*ns of a Raslrate hs :::l -\{iddle zr :- -orm frac- Pectinform (blades,plates, Stellate StelLplanate platforms) Stelllscaphate t' - ,-r: margins. Itc '-:;: internal Pastinale Pastiniplanate Pastiniscaphate E:l-::-:s olfibers Carminate Carminiplanate rr--,: !-:h distinc- Carminiscaphate E|[-=- :: represent Angulate Anguliplanate 4 :: :!\rodonts, Anguliscaphate . Su:=: -ent stud- Segminate Segminiplanate frii: =: hraline Segminiscaphate Bisegminiscaphate mc-_-i =e butlt of Trisegminiscaphate t :i= ::de up of I : r-,-aled par- *r:-: s-:---aces par- plied to thosecategories in Volume W (Supple- Coniform elementsare funher divided into rd :;-' re rodlike ment 2) ofthe Treatiseon InvertebratePaleon- two categories(geniculate and nongeniculdte) t::ity packed toloSy (clafk et al., l98l). on the basis of the type of curvature.Seven l.€-':: Tllus, al- Pander,the first to describeconodont ele- major types of ramiform elementsare recog- r_. erred in ments,divided his specimensinto two major nized on the basisof the number of processes n;,: -.:-:::brm COn- categories,einfache Zahne ax.dzusammenge' and their relationshipto the cusp.Pectiniform e;:. :her \!ere setzteZahne (i. e., "simple or singleteeth" and elementsare divided into five major groupson !-t : =-.rP distin- "compound or compositeteeth"). That divi- the basis of the number and arrangementof E-,i lt|ucture. sion is still useful,although it hasbeen custom- primary processes.If pectiniformelements de- i i-- :s- or neu- ary for many yearsto divide the "compoundor velopplatformlike lateral extensions, they may r:= -:,'luded in composite"category into two or threedivisions be further describedin terms of the resulting termed Ddrs,blades, and plates (ot platforms). shapeofthe attachmentsurface (planate or sca- In the shape classification adopted by Treq- phate).Typical representativesof eachof these

I lr'Jeauthors, Pander's simple or singleteeth are categoriesare shown in Figs.2.2, 2.3,2.4,2.5, coniform (cote-shaped) elemenls;barlike com- and 2.6, which also includeinformation on :s :,:, be much pound or compositeteelh are ramifurm (ray- termsused to describefeatures ofeach ofthese : tc---: :n a wide shaped)element$ and blade- and plate- (or elementtypes. r$- 3:--ause those platform) like elementsare groupedtogether rr :: rhe func- as pectiniform (comb-shaped)elements. Ele- 2.3.1 Coniformcrowns br -::-:ran basis ments describedin Table 2.1 as rastratehave E. :-'.i ol atten- been regardedeither as peculiarly modified Coniform elements,which are also known in =i recogniz- coniform elementsby someauthors or ascom- the literature as "simple cones" or just as --: ri- -ee descrip- pound elementsby others.They werenot spe- "cones,"are basically of conicalshape. Pander IFt | :!. cifically identified in rhe Treatise classification divided elementslike this into two parts, a It!:i--- :s el\'en rn of shapecategories but are here regardedas a more or lessexpanded base, which enclosesa E' -_:: :tames ap- separatecategory for descriptivepurposes. subconicalbasal cavity (Ihe CavitasPulpae of sluelllele urroJru?J Jo sod,q Jofuru ue^os snonsrosuocqll{l slueuralerxroJruos l?suleur 'sassaJold lolapl PeIIIrel er? lueuelo -u.Il(sfll?Jelqrq 'sldru?xeJoC slusuole ruJoJ rrrJoJrur?J? Jo seprseql ol as"q eql Jo suorsuol -ruBJ roJ posnsurJel e qdutsep eql -ye pue lssaJotd toHaluD ue sr dsnc oql Jo sprs Jo JIrJossu^roJc ^[uo,'AoururoJruoJ roJ ezrlrln ot alqrssod Jouolus arB Jo uoqcofoJd IDsDqD sr l?ql ouo eq [?lll tr t?qt lsettlns I 'p"etsul 'eJeqsurel ',ssnotd nua$od E sr dsnc eqlJo eprs 'rouelsod pozq"roedsI"uonlpp? asodoJdot fu?ssoceuoq ro 'o^?tuoc eql qIA\ snonuquos sr l?ql ssocoJd plnoqs lr o^erTeqlou op I 'el?crpurPlno,[ uorl v 'pluoz oq dsnc oql ol Jouetsod os"q eqlJo -EogrsseJcadEqs ploJo^\l e uegl xoldrum oJour uorUod l?rlt Jo ur8Jzrx reddn eql puE dn xod? sr dnort srql urqlr^r uon?ntrs cBoloqfuotu dsnc oql qllr\ 'slueurele ruJoJruoc se Jeuupru ar{l 'lselle ud slueluela uuoJruor qlyA pe)lJo^l elll"s eql ur peluouo aJe slueuele uJoJrr[?ll s?q oq,'aeuo,{uE sE 'Je a,y\oH'dsnc eqt Jo aEpo 'atDln?ltuapDeq rouolsod er{l olul os?q 3ql Jo urtr?ur roddn ,{?tu sessacoJd eIIJos lnq 'saptMap ere ssaJoJd eql Iuo{ uorlrsue4qloor[s 3 sr oJeqlsluorueJe e uo suorl? es pnpr^rpul 'oleJJos (,(lq?u?^ ulJoJruoJawlnnua8ua ur s?eJer{,r\'e[8uE elnJ" -ur lou lnq) ,{IuoluruoJ erc se8peJeddn esoqA\ ue ur dsnc eql Jo urtJ?uj Jouglsodoql surof 'sassnotd rlJro! ot dsnc eql uroJJ ,{e,{r" pepuelxe oseqeql Jo oEpoJeddn oql 'slueuolo rrlJoJruoc eJ" eseq eql Jo ssEpa Jo sop$ eql Jo elorrJ Jo aLo1ntua?uI peqsrn8uusrpare su/r\ororuroJr ouo ..'sJeq,,se z86I eJoJeqeJnlslelrl luopouoc -ooc Jo sed,{l Jof"ur ot t ilao aypatJ eql uI 0IIl JO qsnUr Ur U?r\Ou)I'Slueuiala rrJOJrrU?J UI 'Z'Z 'Ergur potecp -ur ASolourrurole^rlducsep eqt uaqt ,{?ru \_ sa$uJ raroJnlDY z t z euo ',{e,$ srql uI pelueuo su,{ioro^ldde u oJruos oJ 'lzluozuoq eseqsqlJo o8poJoddn oql gll^{ pu? $ 'sluauap runrluoJ anttStp perJrr4 dn sdq Jreql qlld\ peluerJo eJ? sluetuele uuoJr eq lqEru f,lFseq suortca:rp elrsoddo ur 1sr^{l -uoJ 'sgsodJnde^nducsap rod 'saaJtepsnou"A lsqt eelsoc lerolq qlrir\ suuoJ culeurru^se pu? ol po^Jncsr ro tqEre4sraqlra sr leql sIX?EuoI 'stuerrrela (alolnnuaSuou afop Jo) awln7ruaS e seqpuE 'lrun eql Jo xod?eql ol sJed?l'pqos aplD sE pequcsep eq ga.tr lqErur e?lsoc l"rolu I sr qcqlA '(azrrds's,Jepued) dsn, e pu? :(Jepupd

'sEsuE) Jo ,{lrsJe run pu? €clJeuv ilercos eql /kolnoc .^Aolotuoslsd elErqeuo^ul .su^\olcJo lecrSoloeC Jo uo esupolf Iuo{ ur\rErporlqgu uo ruEJS?rC ruloJruocJosed l loferu o^rf eqtyo A8olouluuefpue uoqq uaug .1i3 .B;g

alelncruaOuou atelnJrua6 p -itlsro^run Er sruerS€rc iauroc leseqorelue I lerolel = dl ! = dE :dsnc urOre|'ulessq 'c'z'3!d 'u ll^ec lgseq ,euroc lesgqoJelsod wptnqqtH essq lo ur6Js|rl,addn mq ,.uuoJ alsoS ||- peurel le.l EJB 'sUod eurJ9c Daprs qcee buetsod e SlJletutu^s amlv'Kflo FJJUr OSp I uxroqs el? ! ssuoSelBJ dsnc 'drl to 'rede ue:q 0^?g lo

VJNOCONOJ AHI 9I SKELETALANATOMY l7

have been recognized.Names for theseshape nally form-taxonomic f, of cusp conceptsbased on alate categoriesare listed in Table2.1. Typical forms ramiform-typespecimens. are showndiagrammatically in Fig. 2.3,which Tertiopedateramiform elementsalso have a also includes some information on terminol- posteriorprocess and a lateralprocess on each ogy. Alate ramdorm elemenlsare bilaterally side of the cusp,but the lateral processesare symmetrical,lack an anteriorprocess, but have not symmetricallydisposed with respectto the a posterior processand a lateral processon cusp and the posterior processis commonly eachside of the cusp.In somedescriptive re- long and conspicuouslydenticulated. ports, alate ramiform elements haye been Digyrate ramiform elements are like alate termed "trichonodelliform" or "hibbardelli- elements,but they are individually asymmet- form" becausethe genera Trichonodella and, rical; only rarely is the posteriorprocess well Fg.n of base Hibbardella (and several others) were origi- developedand denticulate;and lateral pro-

!b| C,Oaner hr Fig. 2.3. = il Ramiform crowns and their orientation. Tetus usedto describeth€m include the followns: ac anti- cusp;ap: antetior process;bc = basalcavity;bp = basalpit;c = cusp;d = denticle;ilp = inner laieral process; F lp_= lateralprocess; olp = outer lateralproc€ss; pp = posteriorprocess; and zrm = zoneofrecessive basal margin. FE Diagramsrcdrawn from Trcatiseon InvertebratePaleontology, courtesy ofth€ GeologicalSociety ofAmerica;nd University of Kansas.

ant frh:sa*r fiom ts :r t ansas. I kilEd as 4/4te per elements, Fi co$ae that F[r might be F t I t F rrr-h of the !- -'tan" one f, rre base are + post p-c;'resses, quadrtramate P 161 oo, n- DIIIrlns on a tFRTsses may

|d b ttre same ] rfl rhe cusp !d $ar ponion dolabrate D lorizonEl. A Ce !::Dncave,or processl -elorrd rhe alterior lEEr. and ex- rd a ra-miform olp EA- km eleDents ta.l|opodate ahlo -eq [SoToruoq olqeqoJd oql ezrseqdue ol u?ql .el"lntlue8 uos?eJJeqlo ou JoJJr s" poqursap suuoJ eqt JoJ tuau)p uttoltuot autqopp ^{ou uorsseJdxoeql esn ol et?udordd? eq lq8lt'u fl f 'sseroJd 'tc?J uI Jouelsod eleFcuuep e Euheq uI sluourele uloJruoc elElnorueEuro+ JoJ F ^Iuo .pedsp -Jrp,(eql 'tcedsoJsrql q l?Jet?lur ped?qs {crd ,{IuorullIoc eJ? puE ssecoJd touelsod e e^?g stuauap unlrruDr aptqDpe ^lrro 'eteuueolq ural Iurlneu eq1 ;o ,{1qrqz lI? e qlr^r aseec^llsJntelcueulou [r^\ ecnceJd srgl l?ql pedoq sl tr q8noqlp 'sJed?dcu"ruets^s ouros uI ..urloJ -4uopol,{proc,, Jo ..urJoJrlapoepulq,, peulrel ueeq e^?q sluaurole urJoJrr[eJ oe oleuuodrg 'o1?lnorluep"ss$oJd Jouotsod eqt puE ol"In rl I -IJJq -uep sr ssecoJd Jouelu? egl (snpoutsttg pue . = q puP:^1o!nJ_J:JIJnuJp = p :dsnJ= J:?ur^lolloJoqt JpnlJutruJ-ql equJsep ot pJsn uopouad Jo sorcedsJo sesntaedd? plela{s eql surJeJ .urfueu uorlslueuorreql pue su^rolJ olErlseu .r.z.t!d ur '3'e) ses"c ,\lal B uI dsnr aqlJo uors -uelxe e{rle8uEl} e Aq ,{luo peluesardal sr pue sglcquep $lcel sseJoJdJouolu? eql ,,(Iuoruluoc -?JeJ qlr^{ .suA{oJc JulaUrUr,(S?,{lpnpr^rpur -un loN ',{lFretq 'pelcouop sr ro 'se^rnJ 'pesserduoc" .ErC) e^eq (r.e sluetllale elslls?U -(IIoc pu? ssecoJd Jouelsod egl u?ql Jeuoqs^luouj 'peuroc spl{ alD4sD,t ,sluer[gJa prot'l^ eql pu? pezruEoceJ sI ssecoJdJouolu" eql ujJoJrrrr€Jelpu sB/(reuo roJ poeu eql .dsnc 6t6T ur parlsllqnd I uodar -uodrq lsou.I uI eql 01 lcodseJqlr,t\ uoqrs c4eurals^s ? ur lnq 'sluoluela t4arts roJ asrpatJ -od ur Jouelsod puE Jouelu? eJ? qorqA{.sassec oql ur pesodoJd s€^\ ruJel e^Bduosep pnods -oJd o^,U e^eq .sflrruala uuofnuD,r apuuadrg oN 'dsnr eql Jo urtJ?r.u louelsod o^?cuot oql 'stueluele ateJ^8rp ruJoJr^eJq loJ suon uo selruuep I?Js^esol euo dola^ep AluourrfioJ -?u8rsap Jrutouoxel-urJoJ elo^t snllpu&ortuo sluetllale lnq tIIJoJrrIl"J IsJrd,g Jo soss$oJd -ug pue snqpuSo8tz s?ereq^\ ,stuourele eleJ eql ol elqeJ?duoc selnl3ruts {oel l?ql slrun -,{3rp urJoJrsuolxe JoJ ruloJ ur pela ruioJruoo flJEorseq sft snLlpuBDEaH pue.ourpo -aJc ere^\ snpoqlodsopald^ruouox?l plue snpopo -dsn} laqDtDd'DurpoqlurynJ,ourpopqopnasd,Durp eql qlr^{ aJnlounfJo lurod eql le alnl? JnJ JorJ -opg eJoue?ap4uoporepuEd eqt Jo slueruelA -elsod ro Jouolu? Jreql ur3eq qJrq^\ 'sessecoJdlopoqs gcnur o^?q ol^llproue8 pual Jellpl eql su$onapqsvv t.€.2 'spue I"lsrp Jreql lz ro ,(lJouotue tur - rno etoJeq dsnc aql^llouolsod uro{ pr" Uno ,(lsnonrrds 'sluaLuala -uot puelxe ,{Foururoo 1eq1sessecord pre1zl uttolraot apwotlqnru .slueuele parujel eq tq8ru (pore Suol a^eq rorruoJ eqJ eif-r^trp ulto! -^ocsrp eq re^e,{us pFoqs) ItoloruoelEd sosseJordlnoJ ueqt -hatq pue lanltsuatxa uee^ueq r{srnEuqsrp ol qF rqucsep eJoru qll.t\ esoql s€eJeg,tl ,stuauala ,S unltraD.t InJosn etmb ll pug I leld?qJ ur t?rll t 's'z '3!,{ apuotupDnb sE pequosep ^lolloJ er? suo$snJsrp uI'sasnleJEdd? luo{rrelerllnut snor (l?Jel?l pue o,{l 'Joualsod 'Jouelue)^Iet?udorddp sessaJoJd -Je slueuoduoc el?J,tErpeqt loJ .oJ?J Jo .,urloJrql?u JnoJ qlrn asoql eJ" sessecoJdfu"ruud pup ^{eJ -eoBueue,, ..,urJoJrql?uEo8,(2,,,.,ruloJrluop eerql ueql eJou qll^l EuerrJele uJoJnu"u -oq1edso1ca1d,,..'ruroJrluopolno!, se qcns suJel [srJSJadns .,{uouoxq lueurelorlJnrll pu? sopnpur eJnleJolrl a^rlducsep 9rfl auos htsq selcll Kurouox?l Jo rrrJoJuea,{qeq uorlrsu€Jl Jo J? Jelur 'sueunceds-ed,q uJoJrrrrEl aleJ,(Ary uo peseq lsnJ eql Jo eql ur penedd" luql $Fo,,l\e^rldursep ur ..tutoJ sldecuoJ crruouox?l-urloJ ,{l[?ul8uo eJa/ snql E p [E]aA3S -uuoporuoudoeu,, puz ..uuoJrluopouou^c,, -ouSouuoug pue,snqpu8o&tz,snpoqndsol Fod oqt t" peurJal ueeq osle e^?q uos s trl JO Sluau -JaH 'snpolno ereue8 sq1 ssn"Jag .suoqceJrp zrrals€J?qc -efg 'sorceds luopouoc snoue^ Jo sesnlpJ?d olrsoddo ur e,rrnc fluoruuroc serlrue4 deap lpr{l -oe lelela{s eql ur ed^l srql Jo slueueTe ueeal -xe rl1l1'\ ^la^n Telsrp 'pedole^op ow sessac ^lpnbeun VINOCONOJ EHT 8I SKELETALANATOMY l9 ide skeletalap- tively deep basal cayity and a posterior maryin A few others(e.g., the upper pat in Fig. 2.4) r Fecies. Ele- characterizedby a prominent flangelike "heel" lack a "heel." b been rcrmed at the posterior end and, typically, a seriesof bprioniodonti- seyeral denticles between the heel and the tip 2.3.4 PectiniformUowns l+tpeared in the of the cusp. A few rastrate elements lack den- ]frm E\onomy ticlesbetween heel and cuspapex and are thus In 1879Hinde usedthe term "pectinateteeth" superficiallylike geniculateconiform elements. for comb-shapedconodont elements ofthe sort rban three -eic fu sirh four tuo larcral) Et-;dirumate Fi9.2,5, Pastinateand stellatepectiniform elements,their scaphateand planatederivatives, and terms usedto -.F fce srrh more describethem. (SeeFig. 2.3 for explanation of abbreviations,)Diagams redrawn from Treatiseon Invertebrate Paleontology, courtesy of the Geological Society of America and University of Kansas. fc== be discov- F"lri.amiform F i 7 F. g*ra Belo- Parebel- ant. -_ + post ! cotriform to the past|nale &ren$ but post ._ Sendcles on

6e cusp. No c I in the r slsematrc K)r one was sas coined. compressed, rirh a rela-

stelliplanate

ant <_ oost PoSl -_ ant anl- post. - - - -+

pastiniscaphate stelliscaphate -eq eceJns lueurqcene eql pus dsno eql qt?eu -runcedFcrd,(I 'I U olqel ur pelsll ore sluoul -eq lld ps?q ? ol paJnpar aq f?ur ,(lr ?J aqt ro -ele uuoJrurlrod roJ asuDaJJ eql ur pesodoJd :dsn3 aql qt?euaq q3rq^l 'suoq?urquroc 3a0co,ro spu?dxe srrrreJ tueraJrp ur 'elerJdord ',$l^?J psEq aql Jo^DuE3gruErs suorsuelxo olrTqEnoJl Jo -d" s? 'pesneq pFoc lpqt spro,t\/neu e lsnf lEr.tal ^reJ -eAooJA ur pasolcuo eq ,(eu ecslns lueluqcel uo pes?q e^nducsepE asr^epol -1? eql Jo suorsuelxe sessecoJdesoql Jo sued elqrssodsE^\ ^Solouruuallr'fuoEelm od?r{sJofeu olEurs?Jo rJ^lol Jql uo 'slueu:Ja uloJrtlleJ Jo sesseJoJd sluelJ? se su \oJcJo sedlt eseqlTI? AurpJESoJ uEqt Jeq8rqpuE possoJdruoc,tll?Jelel eJ?sossec ,(q rrJ l9s9q 'uorlrppzu1 snonqo ,(Solouoql"ql sa{Errr -oJd'sluourele uJoJtuqced ssalurloJleld lsour l?qt E ur pequtsop eq pFoqs snqt pu? uI 'dsno eql luo{ ,terre puelxo l?ql sossecord sasnlEr"dde^?,r lelale{s snoue^ ur suoprsodJ?II JnoJse ,(ueu sEol auo pue lrd Jo ,qr^ec l?s?q ? -Iursperdncco ? su.uoJleldpu? 'sel"ld 'sapelq Jo xod? eq1e^oq? pelenlrs sr l?ql dsnJ e Eur^Brl 13ql reelc elmb ueql s",r lr esnEJeqsroqtn? ur Jelruns I[? eJe suorsuedxe pralel e{llrrrJoJ snol\eJd ..suuoJ1eld,,^q Jo..selqd,, poqqnp -leld ro -elqd ]cpl l?qt su,rorc pod?qs-quroJ stueuela ^qopnlJur ol (.,uJoJrurped,,luJoJ eql 'sed^l rur6as aseqlJo slueluele eqrJcsopot uI) ujr01eqtJo uorlrugappeuapsorq I 'ra^e,ror{ pesn surJel aqlJo eruos epnlcur osle qcrqa'r'z 'sluoPouoJuo orljnlo^ aslpalJ 186l etll uI 's8rJ 'sJoqlnE lU^E. p'de '9'Z '9'e ur u.{rogsele sluouela urroJ luonbosqns ,(q ..sepelq,,peuJel lssBq ^uetu ( F pue Jo l"Jlaoroeceql Jo ,,t'ororuosledorerqoue^ul uo ol pesn'uourvsuuol puE'so^qe^uep^rorcos oleuEldpu? oleqd"rs^sounoc Jreql ,sluouele ".,r".rr'iilrufl*?,fi''l,qliilS.9:i .a1i : uloJruncod eteurturecpue elqnauy_ $Y olSuItt rSc oleqoecsrurturec

FFy ge^Iurl pue o nas reddn bs 't'z '3r.{

'mpolstou euros e sern6ll lte -.- d o Jo elelnbue aleueldrlnEue - uroJ eleurl ur6Jeut rr$od 'Jou leseq a^rssacol lo euoz,ull2 *uql o^Eq ssaaord lerelet llepuoaes.dls jpuus0d sseJoJd roualsod -dd ssacord leJalel AJeul|ld-dld Frp qcueJq ulJolleld_ld lo Jouel taal_r I iesseroJd al.rluap-p D stuauap duluc-lt luelue8uEr euuea,ec dsnc-a SuIpuodop d leseq-dq I ur PePr^ apetq-tq EroJl?ld a^oor6 leseq_6q EEq po!e^ Alr^e. leseq,Jq gqr a,toorE oteltns luetrlqcelle-se d aql r{teeu sseco,o lot,ralue.de a^oor6 leuUecpe-6e

VJNOOONOJ AHJ oz SKELETAL ANATOMY 2l

neaththe processesmay havea narrow medial lodina) the anterior process is commonly groovethat is flankedlaterally by zonesof in- adenticulateand is representedonly by a con- vertedbasal margin of varying width. spicuousflangelike rim on the anlerior margin Platformlesspectiniform elements are di- of the cusp. Pastinateelements of this type vided in Table 2.1 into five major categories, havebeen termed "dichognathiform"in some dependingprimarily on the number and ar- of the descriptiveliterature because the genus rangement of processes.Stellate pectindorm Dichognathuswas basedon such elementsin elements(Fig. 2.5) have at leastfour primary the heydayof form taxonomy. processes,of which two are anterior and pos- Carminate and angulate pectinifurm ele- terior. One or more of these processesmay ments (Fig. 2.6) have two primary processes, branch distally to form secondaryprocesses. which are regardedas anterior and posteriorin Pastinate pecliniform elements (Fig. 2.5) position.The categoriesdiffer only in that the have three primary processes,which are ante- longitudinal axis of carminate elements is rior, posterior,and lateral in position. In pas- straight, or essentiallyso, in lateral view, tinate componentsof the skeletalapparatuses whereasthat of angulateelements is archedbe- of some Ordovician conodonts(e.9., Neomul- neaththe cusp.Carminate elements were com- tioistodus, Multioistodus, Phragmodus, Plec- monly termed "spathognathodontiform"and

trig. 2.7. Segminarepectiniform elements, their scaphateand planate derivative$, and terms us€d to describe them. Upper sets ofdiagrams from Treatise on lnvertebrate Paleontology, courtesy of the Geological Society of America and University of Kansas.

fr ' 5. 1.6.and Jte rcrmsused F. l dae- or plat- p d similar in pe rne apex of L oanr as four L tbe .u.p. rn I demen$, pro- higher than -I On the lower bas of the at- hd in groove- h rprel cavity, the cusp; -rlhra bsal pit be- proccaloa rrt srface be- brsogminiscophato trisogminigcsphots iIJql suoD?l -rp J?IrtIIrs i(1eso1colur sru-ro; elEI? clJlauul^se E1. JrSoloqd ,qtqEIIs Jo ,(?^r ep?l8 slueluele alsl? leJulelx ^q Jer{loue Fr3ui lqtrru -ru^s ',{ ?cDsuetJeJ?gJ Jo ^lleJot€lq uuoJ IXSUOTSnO esoql pue edih euo Jo sluauele uoe^\leq aJaql $ 'la^eA\oH fi uo4rsu?rl snonuuuoc lsourl? u? sr xleustsJdns l?ql sJo^ocsrpueuo euo 'seuoEelm edeqs olul rtrsuEJ1-oJnl peuos ale slueuele rrrJoJrrusrJo suollcelloJ sv u aql plseeJ sa!res I| slalduoc uolllsuBrtr-arnF^rnJ puB -tr4ouru S t'Z F"a[ 1? Uoeq EtrEll-elnle^ r s?^1 qcrq^\ 'I Z elqeJ uI pelsrTsluaul tFoloqtuotu -ola uloJrurpad paur:og1qd JoJ surel ZI eql iB lelelols e ol peol (oleueld Jo slpqdecs) ecu.Fns luourqt?l Fr q3Eeleql -l?Jo aJntEupus ( cle 'eteurlsEd'elellets) sessec meerqgc -oJd fu"ujud Jo luelua8uelJe pue Jaqunu Aur l4-,fuleurru,(s -qucsgp srrrJel Jo suorleulquoC uISJ?ur [Eseq ale tEql snl?J e^rsseceJJo ?el? Surpunouns pEorq e pue lrd 6q?Jl-arnl€ I"$q tunsrsum ec?.ljnslusulqoE e ue pu? "Jo rIP SneeJq?d sossocord o,'.\l [Iuo qtl\\ tueurele peuuoJteld JUlEtIITIIAS? peqJJ"un ue .lrluepr plll.o,f. apuoldtutrun)J d.oJ ur esoql uual eql s"oJaq^r 'apqdDJsrulisod parxrel eq :IIos lrqrqxe 'uol eql uo slu.ulele plnondeprsJopun eJ4ue slr sardncJoleql elerq€lopro oleuuedrqoql olul reluoceql ul slueur p suorsJe^ ps"q e pue sesseJord fueruud eerql qlI,,I\^lrl"c luour Jo -oloetepodoruol ro el€ 8rp eqlJo^ror Aer'.' epEr8lqiu paurroSzld aor uI sueut eql uo sluoruoleolqv seraodsluopouoc eerql^q Jo sosnler -ele ujroJruD3ad e stql'apuDld 3qs ,(q reqlo -eddeoql ur souesuoq$ueil-tul6rrtll,{s oql '8 2 't!d oq ol ples sr oceFns sql 'u€l"u Ieseq e^rssaJ E)l3rrrJoJruoc -eJJo eeJeluec"fp? p?orq e pu" dsnc eql qleau m 6 z '8rdJo -eq lrd ps?q E Jo slsrsuoc eceJJnsluaurqceue Er uorlrsu"rl sluJruJJJJo JrnlPu J^tle^rosuoJ 3ql 'le^J^roH sql Jr 'Jo^end.oH'apqdoJs aq 01 pl?s sr scEJlns 'auop { aql Jo rnoJ sluauele ssoql Jo qEnorql sel' luetlIqc"lle eql 'eprsJepun slr Jo lP Jo qcnul roJeJ se 's?l?J -ods cusuoEuocJo sosnl?J"dd?^pnls eql qsrnEu4slp serdnmo l€q1 pseq snorc?dEc z seq 'oJeJlns^lr^m lals aql uI 01 llnrup sl 1r Pu? 'e^4E^Jesuoc luJr!olo Jqr JI luelllqJEllE eql Jo Jd?qs .SAJAD eJ? seues uollrsu?4-fu1alullI^s^luoruluoc eql ur slueur eq1 01 eulPJocce pelueu eJE sluetuolo urloJ 'sluopouoc PrJe 'snw$ -ele Jo sed?qs lsorrl Jo snt?Jedde -luqced el?uurtes pue 'oleF8ue 'eFuIu.u?J I s-ttpotapuDd etelduroc eql dn e{?u leql slueuele Jo sed.{l 'elpu"ld 'el?Uols Jo senSoFue peulJoJleld qJ s? pJeasr ua^es ro xls aql Jo rnoJ ro JJrql lsnf saAJoA ;urJqlroJ sulal eJeoJeql'dn ^'\ou 'DSUO?llSUDtl -ur seuss uorlNuu Jl-fulou.Iuj^s eql 'elnJ e sv uJnl plnoqs Jr 'tnq slueuele uJoJlurlJod Duuet ,tnuec 'Iooq srql eseql Jo suorsJa^^eql eleuEld Jo ssolurroJlEld eJe ry9J 0Jn1?^ ur areq.$asleuaoqs ere sJeqlo snoJeunu Pue eJeql 1?ql oJ"^c tou ulE I sseJojd Jouelsod ou alqeu? eJ€ '8'Z 'BIC ul sorrosuoDrsuEll-futeluu^s pJa^es pue 'sessecoJd l?Jelel o/al ro euo '^ll^?c ps"q I SSrIaSUOUIS ol"JlsnlF I 'stueurele eleJcsrp ,{Iuo peluosoJ daep'peoJq E r0r.,i\ sluellIele peuloJl?Id or" p pelou uaaq -deJ ale l?r seroedsluopouoc ^q Jo sesnl?Edd? qorqA 'suuoJ tllns roJ apqdnstunu8as l pue ns pesodrrjoc Ielelqs eql turlcn4suooar ur ecueuodurr l?JIl atm.ldoJsrutw8asrqsurret aqt etnpoJtur I l Z xt ? uI -c?Jd l"aJEJo eq ol ouroc s"q uonruSoceJJreql '3r{ pu€ I Z elq?I ur pue 'o^u Jo ssa3oJdl?relEl ^\aJ pafloc pu? 'lno pe{ro^\ ueoq e^?q solrosJaqlo flluonb a^?q osle l(€ur sad,tl auros pue Joualsod slr " nduro3 ^u?Josaues -esqns sed,(l pra^es pet?Jlsn[r pu? peq csep l? dsnc oql qlh\ 'ssecoJdJouelu? uz ,tpo ar'zq rll ol uonuel eq pue 'sauas uoutsuoti-li4aluurts tllns ezruSo 0'Z A.c) vuawap unllurlrad apulwSas mqJ '$[rols -c3r 01lsrg oql send.(t96I ) uroJlspurl solerpeu 'Aurouox4 luarueleuFu Jo sesofund {l SIUOpOUOC -relur crEoloqdJorusnoJeunu Jo sruJoJ eql JoJ paldep? Sureq se^\ uJoJ Jo elq?JeprsuoJ el?rqqop ue^e Jo etEuuedrqotur pocEJl^E^\ ^qeq eEenAuq eql ueq^\'s0/61 eqtJo^urouoxel ernlEJelrl a^u uu,{s eql ur 'uJnl ur 'as3ql 'sluou.Ielaalepedoruel Jo aler^8^"tu ducsep aql uI ..urJoJrurpolDzo,, souo 91"lnBuP

VINOCONOJ AHI SKELETAL ANATOMY

It Th.se. in turn, in the symmetry-transitionseries may be of .1 en dolabrate considerablehelp in distinguishingbetween rliologic- inter- conodontsthat belongin differenlsuprageneric 5 '-:< 6rst to rec- stocks.Thus it is important to pay carefulat- fu -..-ies. and he tention to the correctassignment oftransition- A d. 1pes. Subse- seriescomponents during the systematicstudy rr€rt-d out, and of any collectionof discreteelements. th .iereat prac- In a few conodontspecies with apparatuses @g ihe skeletal composedsolely of coniform elements,it has ris :iat are rep- beennoted that positionsin a symmetry-tran- E3 I illustrate sition seriesmay be occupiedby elementsthat rries n Fig. 2.8, are variable with respectto longitudinal cur- IIr .]s€q'here in yature. Fahraeusand Hunter (1986) have re- cently termed these variable gtorrpscurvalure- series in- transitionseries a\d haveillustrated those they --:ont n or seven regard as characteristic of the apparatusesof 'E ::e complete Panderodus gracilis, Protopanderodusvqrico- L *apes of ele- slatus, ajf,d Drepanoistodus sp. aff. D. sub- t..a are erectus. E-1 difficult-ries to In the skeletal apparatus of Panderodusgra- fcncgrneric spe- ciri, asreconstructed by Fihraeusand Hunter, r &enls alone. four ofthe five componentsform a symmetry- tr3 of elements transitionseries (Fig. 2.9).Specimens in row A ofFig. 2.9 are all bilaterallysymmetrical, alate coniformelements, but theydiffer from onean- I c-E in the appa- other by slight variations in curvature;speci- h aFaents on the mensin row B. whichare slightly asymmetric !- r=_jopedarc ele- iipr_: or dolabrale versionsof the alatespecimens in row A, also exhibit some variation in curvature, as do thosein row C, which are otherwiseeven more asymmetric versions of elementsin row B. Fihraeus and Hunter tius recognizefive cur- vature-transitionseries within a skeletalappa- ratus or four-member Fig.2.9. The curvatur e-transilion seies of Panderodus that alsoexhibits a three- gracilrs(Branson and Mehl). Each of the five or six ele- symmetry-transitionseries. ments oflhe apparatusis shownto increasein curvature Fihraeus and Hunter evidently conclude away fiom the planeofbilateral symmetry.Inner lateral individual Panderodusgracilis had, views on lefl; outerlaleral views on dght. Redrawnfrom that each of F6hraeusand Hunter ( 1985). a skeletalapparatus in which there were five morphologicallydistinct components,each of which was representedby a six-membercur- 2.5 SkeletalApparatuses vature-transitionseries. Thus there must have beenat least 30 elementsin the skeletonof a We have thus far consideredthe composition, complete individual. Fihraeus and Hunter classification,and descriptiveterminology for j regard the nature and number of such curva- discretecomponents of the skeletalapparatuses ture-transition seriesas featuresof potential ofconodonts.However, it hasbeen known for supragenericvalue in conodont taxonomy. at least the last 50 years that in many con- However.they do nol seemto have given se- odonts,perhaps in all of them, the skeletalap- rious considerationto the possibilitythat they paratusincluded elementsof severaldifferent rnight merely be charting the breadth of mor- shapecategories. Thus, in order to compare U phologic particular popu- variation within the one conodontwith anotherand to build a bio- lationsthev samDled. logically reasonabletaxonomy for the group, o(IB-\ Suolue ola^8lp urJoJr.{arq ro 'eteuuedrq 'et"rq"Iop ol luzuodurr sl lr 'aslpatJ oql ur pelou sV o rsasselJJo perlcreeq.4pru qcq^{'slueuele (..urJoJrllol?u,, 'Jr?d olEurs ? aue.l D6I) ro) ped?qs-IcrdJo ll"d eFurs e peldno uEqt eJou ,{q sueJ?ddE eql ur poluoseJdeJ aJe^\ ftlo-€ urEue3 -co Alpcrlsuep?Eqr sr uoDrsodW eql^q (suo4 3lrs le ssoql ro u?ql te8Je[ r{cntu x) JaqlPJSetr I tI fI -Isod qd pue ?d eql peurJeleq,(eur ueeq^u? e^pq tq8ru slueruele lequrnu plol p eq1 ol pol Jo suortrsodoql Jo)slueurele qd pu? ed^dncco peleu eql pue 'perr"d ,(lq?Isuouep tou snql pue nJEJd p?eJds -8rsep^aql aq feru aseqJ 'snleJeddEqcBe ur esaql alep s?^1sod& aqtJo euoJr se r\ol s€ ueeq t" Juo seJ .pue €l Jo Jo sad,{l o^\l ere oJeqt 'elnl s" (sluoruole e^"q lq8ru requnu eql q8noqlF '(sluaurolo urEd lusruelo " eteJ,t8rpuuoJrsuelxe''t'o) slueuele uuoJnx?l Jo sed,{l luorogrp ue^es eql [xap ro) uel pezrlEroods,{q lo sluoureleuuoJrurped ,{q perd Jo qc?eJo rrzd euo)^llEc€oloqtuour sluaurele eleJrsrp tl tseel I rr 13qr 0961 -ncaoeJe suoUrsod d se3?lquesseIanlsu uI le papnlcur e^"q plno^\ snlpJEddeelpJqruorurl tprs qloq uo '01'Z'ErC ur S pue 'tr^['d perelloler? qcrq,{r\.'seu -das elsldluof, E t?r ,tlelrT sr snqJ 'ed& cFoI aD sluauelo tr -oEot?clEdrouud ean0 olur ,{1peat peleredas -ogfuolu euo ,(ueJo sr?d os oq ,(e['uelaql rR 'lmuleur JpJe eq up3setelquess? alalduoc ,tq pelues 'snl?ledde ue tB E ur sJr"d g8eurr-lourut prg^\ 'slueur IUnl?u 'pu? -erdal sorcedslsorrr sesnl?Jedde uI Jncco sluopouoo snlel?ddE eql ETears uJel Jo I?lelels Jo l?laloIs eql leqt p"J eqt uo ,{[u?ruudpeseq sr euaqcs slueuodruoc eql lsour 'sr l?qJ sluauod bp teqt seuo Jo Jo t?qI 0I'Z '8rC ur ,( ucu?urureJEprppel?Jl lueuela-qoJoslp ueles ueql eJoru rnoJ ruerll --Irroo Jo -sn r eueqos eql SurpueuruoreJi(q pepnl3 e^erl,{puJ snleJ?dde ^u"u sodruoc a{rT lEtelels aeJquror.urldes -uoc PUEsrql op ol peshep ueeq e^Eq l?qt leql sraq olou 01 eepr poot e ,{lqeqoJd sr lI x) alarssrpJo " suels^s oql Jo preles pessnosrpI as1nalJ e\1, 'slueurelaJo sJdfl lu: fue^ selel tI 'snlBJadde uI oql uql[^1 suo4rsodsnoSolour -raglp ue^es Jo snl?Jedde ue LV pus -oq Surueu puz 8ur.,lrluepr:o3 eueqJs ? o^eq s?q qJ?a^ll?JrtoloqdJou 1?q1,{luo-ou?s 3ql oJe slueuodtrro3 Fqru s 9'z eql l3r{1 'Js^a/rloq lou seop sasnl?J?d -de el"Jqrueuqdes p€q"{ldlur sluopouoc lueJe.grp o^\l 's?sus) ,{trsle^tun puE Jo EJueuV l"ql uoqeururelap ro /fte^oJsrq 'pesn ,{[apr{l TE lE PEIru Jo,{ppos IpcFolooC equo,{se!noc,^Sololuoel?d eterq -4il4,{ul uo esrlee{ ruo{ pevrporu pue .suorl eq ol tuuu€eq sr peuoBueur lsnf lsour u^rElpeu lstala{s -Isod rofEru Aupeu8rsoploJ urolsxse sepr^ord eql pu" 'lnJssaccnsueeq s?q aueqcs^SolourruJel o^4ducs ros s? 'seues lI :slueruelrJosed^l snoue^ suo[rsod Jo lenpg aoqs^Ielou ot -ep srqt eBJEtpue ,{g 'pesodruor eJe sod elepeur popuolurtou sr deur eqJ .snlsEdalBelelqueul4das e ur .0I.2 .8lf, qJlq^r^leJnd sedr(l purlstp ^eql ot al?udoJd slueuele JoJuonqou lEuortecolJo euoqcs Jo tuollIele -roru requnu eql uo Supuadop^ll?JrSoloqd 'seuoEel?c lsurzJup"nb ps Jo aQJqulauqdas pue'antquaulxas'atotquau elJrulSUOJer -mbumb'aptquautuponb'aptqwauuj'aptq seuss I 9q?[ s -uautq otar peputpqns eq fuo8al?o reD?l oqt €U uI 'c-qs I lew pue alotqwaullnut Jo alDtqwaulun s2 lDlur lue^ul "'l fldurs pequcsep aq sluopouoc Jo sesnleJ€dd? { pue eq ss 5 I?lala{s eql leql potse8:ins aql aI uroJlsurlsrp qs ? I'asuoatJ , es i 'seuoBslec:noJ ro eelql uEql eJoru q ,ieui eJeql +":. ou eAIoAur saureqcsasoql 'u?d ogl Joc u"J?ddE eqt lsoru / 'pelueseJdoJsesnluJEdd€ aql ,tJrss"lcol pelue^ puE lurod + F -uI ueeq e^eq serueqossnoue^ pu? 'JlEuts rfrrJoJ sePr^ -?qoJd s?^i su.leDed lof€ur Jequnu^lq I peuoDueut l"lelals Jo aql leql peuluol J^Drl J^l .r.rrrsnlJpasnl pue E)IueleuJoJ l,1l -i;- saSolquassD eseql uroJC serlquess? uoursodcS n -+- lonpu pru?d lseel le lueseldel ol rrroesosl? ru BIp?,{q Ieu€uo JaueJoqI ctl?qdsoqd,(q reqlaSot pleq x) urJoJruoc tuourec slueurele sJelsnlJ ur?luoJ suorpelloc Jeqlo JILL Jo 1'96I) ,{u?tu pu? 'pele^ocsrp ueeq a\ou e^?q sasnl?l uos aql qd Jo -edd? ololduoc ssal Jo aJour u?ql elo]Al sauJs aq1 d ? 3 ?qd 00S s 3 '11a,rse 'ueq1 ro1 .{Soloululel sruos aq ol paeu EalA sad,tl ed eJeql 'esJnoc sasnl"J?dde r rruoJrueJ t +ed llr^\ Jo 'puv lelole)s lerrxao lerlsruts ol uoruuoc surelled eql Joprsuor lsnur osl€ e,$

VINOCONOJ IIHJ SKELETALANATOMY

ramiform elements or geniculate coniform trateddiagrammatically in Fig. 2.1L In Lane's types.Elements in the threemajor positionsin scheme,C/ass I symmetry is exhibited by ele- the S seriesform a symmetry-transition series mentsthat are themselvesbilaterally symmet- of the sort first recognized by Lindstrdm rical. For suchelements (e.g., alate coniform or (1964).The Saposition is occupiedby an alate ramiform elements) no pairs can be estab- coniform or ramiform element;the Sb position lished,and it is possiblethat they occurredsin- by a digyrate or tertiopedate element; and the gly in skeletal apparatusesor were paied with Sc position by a bipennate or dolabrate rami other individually symmetrical Class I ele- form element. However, the nomenclaturejust ments. C/aJs 11 slrmmetry is a feature of indi- mentioned (and illustrated in Fig. 2.10) pro- vidually asymmetricelements that are repre- vides formal identification for just the mid- sented by approximately equal numbers of point and the two extremesin the S series.In "rights" and "lefts" in largecollections of dis- the apparatusesof many conodonts, however, crete specimens.As lane (1968) noted, the there may be more than three morphologically bulk of known typesof conodontelements ap- distinct componentsof the S seriesand, to de- parentlybelong in this class. scribe and locate them, it may be necessaryto ClassIII symmetry is exhibited by conodont invent intermediate categoriessuch as Sa-b or elementpairs in which the "right" and "1eft" Sb-c.In Fig. 2.10there is alsoa positionin the S serieslabeled Sd, which is occupied in some reconstructed Fig.2.ll. Various symmetry classesexhibited by ele- septimembrate apparatuses by ments typica.l of (I) R hipidognathusi (Jl\ Xaniognathus; quadriramate ramiform elements.It is not ap- (llla) Eognat hoduii (lllb) A mory hoghalhus. propriate to use Sd as the designationfor inter- for elements B nol intended mediate positions in the symmetry-transition of€lement$;it series,as some authors have recenfly done, In rnajor posl- most skeletalapparatuses the Sd position is not on IDverte- Society of filled at all.

2,6 SymneFyof Elements,Elem€nt Psirs, Eaming ho- and Apparatuses 4rFratus. In It takes rrery little experiencewith collections €f rhe systems ofdiscreteconodont elements to discoverthat, rhis and con- like componentsof the human skeleton,most scheme illus- of them corne in mirror-image pairs. The only 210. That ones that depart very obviously from this pat- frct that the tem are alate coniform and ramiform ele- qEcres repre- ments, which are themselves bilaterally sym- can be metrical, and a few straight pectiniform catego- elements that are developed in the same way S in Fig.2.10. on both sides. Indeed, it was not until almost are occu- 1960 that it becameobvious that the right and ['specialized left (or dextral and sinistral) mernbersof some digyrate element pairs are not exact mirror-image repli- two types of cas of one another; and the incieasingly wide- ma;- be desig- spread practice of multielement taxonomy has pmitions they led to the discovery that bilateral asymmetry aDd Pb posi wasrather common in the skeletonsofat least certain groups of conodonts. it-shaped (or Iane (1968)suggested that four major types, may be fiched or classes,of symmetry could be recognized drgyrate among various element pairs. These are illus- puE ,fulo('ulu,(s sp"u?J ur'uetuo^ec aqlJo suorsl^rpel?qs lq8u lnq EIII Jo II sselC o^eq eeseqaCpuP uollrtrr"H eql uo+ pup'uppnlrs ,{ltpJl ,{eur sluJrxeTo qrns ecueq :snl€l Jiq*:errrseqr ur srueuero qcns rerro qlr^\ .?iqT,l?r"$',$;t;";",3"i;:"J,tii":"^1513," ' -zss-ivsYtt io1i" pat ea tuleuru^s AI ss?lJ qlr.r slualuelol?ql -uoI cos loag f UonO sureureJu?eJ?lsruc elmrpul ol luerol$ns,(ForuruoJ eJe sarcuonbe{ .f ,sr slr pu?poq-euoq aqruO (lggt) '. olr"H paleFq?l legJ .en8o^olur erour pu? eJorr] ^{otpnl 't€ 'Z 89-0t tuoolDd euoJ seq suorlJalloretrel Jo srs,tpu?rrurouo f:;:W?"lff':t:{:fl!:;;.,i1"6:i)!!!- poJeedd?srpspq,, :i roJlir peeu 1i"i,r"rri",,1.€eql pue'lecrleroaql fi-S fe ti,ii.ia'""t K1uosr^reBI?T sseJc'tu1eul -uopouoJrep srsegerp roqn (/961) 'IA 'ssoro -ur^s slql 'pozluSoceJeuq sV pezruSoreJeq '68r-LLr . 'O/dgg ottuojb4 uoaDpd Dpv uzc suorsrell?Jlsrurs pue prlxep qcrqr,r[q '8ur (Eleluopouoc'"ec€luopocersro 'eor"luopoJsp -^oq pre1e1se qcns 'seJnleal rcer leqlslueusJa -ued)sesnl?,sdde luopouoJ auoc-elduls ,fttaru _Jtlos r"rr-tuia" rn"'nfr^rpurt,- t sgpnJcurqJr rlt Jo ued IEJAJIu1 :seues uoqrsugJl-JJnIEAJnJ --l'."_: ' ssDl) e pezuSocal osp (896I) eqJ (986I) U o '.roiunH pui ' a r 'sne?rqgc -ul[s 1l ou?'I 'otl-g€l '8I luoapd l'stuopo 'leJlsluls sfE^\I? uotsJe^ .,pep?lquou,, -uocJo uorlrsoduoc eqJ (tt6l) rf'd S'uosIIIg eqt pu? IeJtxap s.{eale sr uorsle^ ..pepplq,, .Arunpu'Ecua"'v."os 1o"e.aa sq7,ffi '(EauElleosrlI) 11 t4 '(uosrqoX y ;ll ;:Til:illfi:"H#:3"::::Jl,:"r"i::,1 -puoapd awtqatn^q uo asuoatJ ri {;ifi; Ienba '{lelerulxoJdd? ur rncco suolsle^ o^u oqJ 'lou -uo3 (1861) I'V'slJleH pu€ 'J'f 'rellrhl sr lequeur leJlsrulseqlJo leql seeJeq^\ .) ,rolllw ,applq 'JI 'ru,o.J1spur.I''t \e6elz'.f snonrrdsuoc ? sE pedole^ep sr Jred "I H C TapoqU'-I 'urlsnv ' 'tJdd"tx < U C eqlJo requreur IEIxep oql Jo ssero.rdrouetu€ ''IAI 'ruoisSrag 'a 'tee^\s "l 'c 'Ir?lJ "..r.nr^o11 S J .ssssecordtu?puoJss pu? fu'ru "qt saJuaraJeu -udJo luauoEu?rs pue requrnu ur pu? eurnno ur Q?rquepr lou,{[alns lnq) lelrrurs ele Jrzd eqt Jo sJeqrueu (IBrlsrurs pu€ latxop Jo) Uol 'poqs{q?lse uaaq sEq tr qrrq.{ pu€ lq8lr t?ql eloN.(tt.Z BtS) eldul€xo tuel uI sluopouo3 6soql Jo luautdolo^op Jo aJIIJo -lecxe uE s? e^Jes,sntJ^opto sntlwu&oqdloluv epour eqlJo uoq?leltue1u ur qlr,1all?ep eq uercnopro etE.I eqt Jo stueruale ed elEqdms ol arnl"oJ Jeqtoue,{loJerusr ^u? fulaulur,{sy fu1au -r11e1s,xeldtrroJoql .g96t ur ere^\,(oql ueql -ulfs l?rel?Iq ruorg fllear8 pouedop oloq.{ € A\ou snoJetunu uour Alqeraprsuoc eJe (euE-I s? peAu"Je Ierrrru? orll l?ql Jo ,(lpculeuur,tse ,{q qlIJ ssoD paqqnp) d:leruur^s III ss?lJ Jo eJenr slueuodruoc Joqlo lpql u?eu lou peeu ,{leu? srqlJo soIduEXA .eruaun3Jo-oJ JrqdeJE uolalols eql Jo slueuoduroJ ur?loc Jo ,fulatx -rteJ$ puE orqd?J8oeApu? aJuepunqe Jelrurs 'l?cule('uru,{s -u se lErel?lrq 'le^e,,AoH ,{q ,(po .rred pur8uo u? Jo sued s? peqsllq?l -t€[Iq uaeq e^?q lou lr{Erur sesnlEJedd?I?laleIS ^ll?ro -se eq uec pu? lcuuslp elrnb ,{Jpcr8oloqtuoru rreql ur srrpd gcns qll { sluopouoc 1?gl lse8 eJ?teql sJequler[ pepu?q-UoTpu? -lqEu se^lo^ ol ro-uorleleJdJelur u? qcns qcuol^r rnz -8ns olur -ur Aleuru^s IJI ssEIC Jo ed{l puoces V 4J 18961) ,(e{uour "H'Jauzlsrd e ot Jeedd? lqSrut ,&teurur^s tulauw/k DIII ssolJ dllerurufsE Jo ed,{l 1".! ^lorql .^\oJ fr t6 'StnqsDl III sselJ qfl/( srr"d luerllalaJo eJualsue po8pa srql peruJel (g96I) eue-I elJrluep pu?q-Uel lAno9 ueqJsrl l^\oDlc?-^\ou eql fu1eurru,4sprelegqJo euEld eqt surofll?d eJo sleqrueu qloqJo ssecoJdJou rlrs sJp eqcsrc ,(II.Z .BrC) eql Jo seprs elrsoddo uo ueoq e,r€r{ ueql tsnul -olue a{rTop"lq eql lnq Aur^{oq IEra I -H J 'rsPuEd '€€ '^poq ro uoFlo{s s.luopouoc e ur pat€nlrs ueoq -1e1ur sacuersgrp,4q pogrluepr ar? rred ?Jo sroq .socqJns Epu"d erlrruq e^Eq ,(eur sJred esor le^eJeq \ 'sJr"d lueui -ureu pepu?q-Uel pue -lqBRI Jeddn funqJnsrelun -elo Jo sJoqureu eusoddo 'pculeluru,ts rragl uo salJrluepJo alqnop e dole^ep lEql ^ror fi pue '- -l?Iq sa^lesrrJaqloJe^\ sluopouoJ l?ql uorurdo^llae slueuelo uJoJlurl5ed eleqd?csrultrJ€r pe,rloq Fo.I 'rlEPJelS pleq ,(ll?JeuaE ,snpqns eq1 JoJ elqrsuodsor ,{Iueurud sr ele qcrq^\ snpolltDu&og Jo ) -l\ 'urgrtspul'l ,futeuru,(s srred tueuala-luopouoJ Jo ,tuteruu,{s (II sselJ stueruele^llerelq ed egt petrc eurl sselJ r'srcd-lueru III Jo) e8?urr-Joutul pa^Jesqo ,(Fouluoc eql auo .suos 8t) N H '3uE.l Jo uos Jo eldtu?xa ue sV luele.Urp '89€-tS€'S€ 'pegDuapr o^!Jo pu? elqereprsuoJJo tq8ls eq aJue BS p3rrun eql eq louuec tsnl rrEd ? Jo sJeqtllelll Uel puB -te.Ulp eqJ Je.Urp^?urslequleru ^lpcrtoloqdJorr] VINOOONOJ EHJ- SKELETALANATOMY i -'-csr cannot be the United Stltes. Quafi. J. Geol.Soc. London Mikromorphologie der Cor.odor]]!e[ Paleonto- 35,351-368. graphica, 128, ll 5-l 52. r::Tor-lmage (or Lane, H. R. (1868). Symmetry in conodont ele- Roundy, P. V. (1926).The micro-fauna.In, P. V. ment-pairs. Paleont.42, 1258-1263. Roundy, G. H. Girty, and M. I. Goldman, Mis- h:-

k-s:---om. S. M., k:c=:. F. H. T., I-=istrom. - M., \ G ,9El ). Con- rc.::a Paleontol- L I \fi5cellanea), flme:,-a and Univ. rl:s-ion of con- llf- D- R 1986).The h:-=:al part of l4ttri:-.ruses (Pan- E- C-.nodonlata). ---189. Dar IE =r Conodon- b ;e: Gatrungen ft C:xodontida). r a.:,:-bed and its I ,i;:. Soc.Lon- nir:s from the |' :, -le Cambro- ih-. ard Genesee fu = Canadaand 8Z tEopouoc peuol qslltocs eql ruo{ suourrJedspuoqrppe 8ur aqrJosuorlod lusJeJrpe^Jesard osp '?la FuoJ ? sesolcue -qFcsep(986I ''Ie te e8puplv) rededretq E uI ^poq-uat lueregrp oml lsBelte lueseJdeJ is3q oql Jo eqol .. I"Jo^rnbe,,sz peg4ueprosl? aJa^isuoBeloJd qcrq,,a'sueurcads uellueur(I qsulms ^lluepr^eJnoJeqJ m sv 'el?rJdord -rotureseqt lng 'qsgpue snxoqdureJo(qrolq suarulJadssnoraJluoqrBJ rlsqloJs oql I'€ foqdal vrJel e\L elcsnurro) sourolo^Iueql qtl,,r\ I arew'(986I) ]P pepdruoc eJe.{\puz ..uorlelueu8es,,^lpuorsr^ordlsetEns #lug (q ,,peaq,, ol uel4,{la^u"lu5l Jeql?JoJea suorsseJdurr '^toloqtuoul ur p4"rJosse g'(l't '8rC)suaur pad?qs-AaW '(I'€ 8rC :9861 'lE le s3!lFg) lsoru oq 01 uroes sluopouoc?J?d qcq^\^lesolc qlr^\ ; 3ql Jo auo .{Iuo suerurcedsqs! ocs aql Jo (e^qcn4sur lsotu 'sql?u8ole?qceql uro+ ur luaraJrp roJo seuJllno oqluns pu?) rsry oqr Jo t",tu"i:"j.:l]#"" elrnb osJE se,..^urolEu?smldLtSotuopo 'l|..ooq oll ur srlr q8noql slql ur uo4eJeprsuoc^Iluepr^e ruo:; pellnuo sr dnorE ItrE JO UOTSSnCSTp puE punq eJoJeqlsnf uaurceds eql Jo uonJol tErO pue l.uopouoc?JedB ueeq e^?q ,{leJns r leuuanuur ollnb Jo llnsoJ ? se sduqred ',(lroue$od palcelrp oq 01 plnoa 1r'luopouo3 se,!\(peu?u s?,,r{uaurrJeds " r srgJ ,,'selr[IIos,, nedd? s.A lsouJJorJolueoqlJo socrdeuourceds eW se)snqduSotuopo Jr 'Jo e,'aoH'sluopouoc pegrluopl h eJe l?ql ur 'Jo e^roH {urul eql Jo Pue rouelu? roJ Iopour Jllrroleu? IEJeusa? s? poJeprsuoc FIE3OI Uerlu?ur(I aql ol lsorrrJEpsalxe s nlJnrs p3d?qs-A Jql ,{lsnouessE^\ uouJrceds u?uquleC olpprw srql 'suelurceds qsrDors ,fuelugruA?{J eql Jo euo uI 'eulu JoJ'os stueureleellluoPoum Pepnlc 'Jouelu? " oql 01 6u[urod s.A eql Jo secrdeqlrAr -uI o^?q ?urtuo lqtru ?rqu.rnToJqspFg 'edEqsolq-/\ € e^pq ot uaeseq qorq^\ ^ +uesro)souolspues Jo el?r{SsseSJng snou?J eql uro{ el"roqdoqdot psoJ 8ur,{oqspeoq ut '(986I) F raetplrptv,(q psqucsep ^Eur ^eql(Z'€ 8rC) pequ3sepun,{Fnor,lord e ur suorsserdrurpe^Jes 'Attr ESopttJ Te suorurcedspe^JosoJd-lle^r ssel eoJgl eql ur lcuq -aJd,(lJoodtpqt pelse8ilnssuJol,^{ ,{e^{uoJ 9t6l -slp:Joui ore saJnlJrulsJseqI'rouelsod eql ur 'oslv erag possncsrplou eJe 'srol?o prB {o1 edoF l€ql seJnpruts Jeln8eJr €€ euos tuopouocJodnoJ8 (lJurlsp ^eqJpue) pezru Jo sJu:s e sr qrrqa Jo Jprs Juo uo 'uorssJldtul -EoceJun,4[snor^eJd € lnq 'sluopouoJ^lqrssod lou ere l?euq lcu4srp ? pe{rEur sr {urut aql Jo sueurrJadsesoql l?ql 'Je^e,$oq'oslo ouo,{Jo^a srxe eql 'ra^o1aoq^q'spJlql o,dl Jouolsod eql uI ,{lT?nur^Jo uorurdoeql sl 1I etepJoqrotuopo 'pue louelue slr Jeeu suorsseldlur J?eurl lourl -uoJ runl^qd Jleql roJ srsuqeql peuroJ pug -srpul Jo Jred lell?Edqns € roJ ldecxe sornl?eJ sluopouo3eq ot (€16I) llocs pue uotlel{ Aq JqsouEerp s{3?l (l € 'trd) uourrcedspa^Jeseld lq8noql era,nEuuluoIAI ur slcoJ uerddrssrssrl -lseq eq1 ur lurul eqt Jo pJrql rorjelu? eql txo{ suerurcedslpuoqrpp? Iere^es ursuoJsrld 'uU peuoddns-,{"r E ur elruolop ueunllsE r!o+ euopue 'puplloJs 0q ot petertuatur sr leq^\Jo serul sJ? 'rorelsod 'qfunqurpEJeeu (u?rddrssrssrl l) snoJoJruoq&C oq ol petpnf 'puo elrsoddo eg1Jo urEJeu euo J:^\Ol Jql Ur PJq Urql P UrO{ JnOJ'SUetUI'JdS uO 'aqol crpqdec Jouetu? ue se pepJ?8arsr pup o^g $nt Jo slsrsuocsluopouoc Jo snl"J"dd€ luopouoo elalduroJ E sesolcue pue gos aql Jo ocuepl^e o^Doefqo'alou ^uroleu? ueAE euo t? uorsserdulrpaqolrq 'snoqFq V opr^\ ( ur ',{urol?u?I?ruru?-eloq^\ Jo sldecuoc 80 0 ot t0'0) rulll 56'l pue 8l uee^\Fq puE Suol eseqol qcqr\ uo ef,uepr^alJerrp el I ueoq ('ur 9 D ru['u S'0t sr (l € '3U :€861 ''le te s8ilug) seqeJar{l '^pumer alrnbIqun 'pup Z ratd"qC ur uourceds pe^resaJd ,{l4olduroc lsour ogl pequ3soposoqt e{ll sluetueleJrleqdsoqd 'ruroJ ul elrllrrJo^\ pue 'pJssJd go flerrlue lsorulzdn apelx sr 'ro,\o^\oq'pro3eJ ^ull -uoJ ,(ll?Jelq 'el"euole ere^\ sluoru?p{ e$ql IrssoJrreql slEruruepJrpoq-Uos )^{ rrro{JpepnJlsuocer slEuJru?eql qloq 'Je e,,AoH stuopouoct€ql 'oluu lsru eql JoJuraqt ^le8relpasouS? 'slcedse lueJoJrp legnd.oruos ur ,{0uoJudd? -rp Jepu€duoq^\ '99gI ecursJ?elc ueeq s"q 1I

AI^IOJVNV'IVruINV-A'IOH,&\'g WHOLE-ANIMALANATOMY 29

2mm G_-i:3nt aspects. :f:::s-,1!cted from E- iirrally com- E ts.:.ld specimen ir i inm (1.6in.) i == ,.07to 0.08 lE:r-sron at one !:c,-:t apparatus r.=:::1ic lobe.On r*: _'rdged to be t =:: :reted to be f::i r. the best- lr i:!i diagnostic ak ::,r of indis- r:i .r'rtenorend. hc ::-.:r- the axis L::ilrnct linear ft::: :s a seriesof !bi: srop€ toward rs a-. more dis- e-, :d specimens Fig. 3.1. Clydagnathlls? sp. cf. C ca,rutbrmis. (A\ Cafiera-lucidadmwing of part; (B) and (C) enlargedvrews of EE :: :.1.( 1986),in head showing conodont assemblagein part (B) and counterpan(C).Specimen from "shnmp-band" in Granron Fe : \--like shape, Sandstones(Dinantian), Edinburgh,Scolland. Redrawn from Bflggs,Clarkson, and Aldridge (1983). E:: rhe anterior. rtt='r specimens, I a]rost to the Dinantian locality, these V-shapedstructures specimento be identifiedas Clydagnathus'lsp. I{: -:r'er. in that are identified, with no further discussion,as cf. C. cavusformis. E=:sr \-'s appear "somites." This interpretationwas obviously In the only Scottishspecimen to preservethe di---'< as a result of quite influential in the much more subjectiye cephaliclobe, right and left componentsofthe k-: --eburial and discussionofanatomy in the 1986paper. even skeletalapparatus are superimposedinstead of thoughit is in no way requiredby the evidence. arrayedon oppositesides of a line of bilateral ft=: and still the Outlinesofthe anteriorend arepreserved in symmetry.It is thus reasonableto supposethat c$::s:r Specrmens only one of the ScottishCarboniferous speci- the cephaliclobe of this specimenis preserved -l - --:e V-shaped mens(Fig. 3.1). Although this end is termedthe in lateral aspect,that is, that the plane of the E:r 3h laken to "head" by Briggset al. (1983)and Aldridge et bedding approximatesthe plane of bilateral | ::re compared al. (1986),there is no evidencein it ofa brain. symmetry.The deepcleft at the anteriorend of b=5 (or muscle The term cephaliclobe may thus be more ap- the cephaliclobe may thus mark the position L B--: lhese inter- propriate. As noted previously, the cephalic ofthe mouth, and the positionofthe apparatus d 'equivocal." lobe of the best-preservedScottish specimen within the cephaliclobe may indicatethe gen- aL- i iS6) describ- enclosesa completeand apparentlylittle dis- eral position of a buccal cayity. If the entire ic= rhe Scottish torted conodontapparatus, which permits the specimenshown in Fig. 3.1 has beenflattened .rellg Itl1'a 'Jo el!\oH eql al?Jrpur osp ,t?rrj puE tuJoJruue^ € E ur r erlr Jo qfual I?mnq unrleqlrde pelElJr3 Jo selc?luel Jo repur?urar eql ol snleJ?dd?^poqIelelqs elsldruoJ or -ila{l lsour JoJsuoddns e^rss€dssel Jo oJoru se pe^Jes E sel?leJ ,(lSurJur uoc ualurJeds snoleJruoq ^[uo I s-6? I slueur e^?q ,{"u snq} pu? elqe^orutllr aJeAl ,{eql -reC qs[lors po^JeseJd-lssq eqt q8noqflv hpr,rlP unldas Jeqleq \ ro qleel pu? sJodwlS s? pa^Jos e^?q (186I ' 3'e) sred?d tue3 snql !l tEurpnlfuol lq8rru pue eTq"^our ej9,,ir snteJ?dde eqt -eJ l€Je^es ur [ocrN ,tq peulnsse euo eql qlr \ ,pasod e ?Jorlcolou 3 Jo stueulele Jeqtaqa olur tqtrsur ou pue osp pue I/61 ur uossddel ,{q ap?ul auo qll^l rn)l sernpruls -x0 Jo lunrlaqlrde urqlr^\ pasolcue se/A snlel eJns?aure8J3I uI seeJAEluotue8uElJE lueualo -"dd? eq1 Joqleqll br tqSnu sauq luopouoc ol s? uorlDrruoJur Jo uou?lardJetur sql 'p(IItu€ eqt Jo srx€ Suol ou epr^oJd ,uoqs .snl €pttptV,{poq suauncedsqslDoJS ogt uI agt qll^\ Ielpnd tou pue ot IerIJou ueeq e^?q .pesoddo luB eql uo sqol -?Jpdd? xeldruoc t?qt ol?nl3e tsql salJsnu eql IIe^\ ,4?ursex? I?urpnl€uol reql tnq 3 ulo{ Surpuel Jo lueuqJe ? Jo atrs 3ql s? pu? qleal pnSurJ ,{llueJ"dd? eJe^\ seJelns Jo sur8l€u poleln3rl eql JoJel€Jlsqns snouIE?[IU€3 p 06uol eqt q1l,1d s? se^JesqJrq/( -uep JreqJ ',{Ieurur,4s leJelelrq Jo ouqd eqt 'saqsg8pq eqt pll?Jedqns Jo Jo el?ld Fs?q eql 01 alqer?d Jo seprsal$oddo uo petenlrs pup sorJasS eqlJo EIJeds qsltlocs -ruoc ejnlJnJls ? Jo lu?uruoJ eql sE peleJdJalur ssoql ol Jouelsod ecu?lsrpeluos ,{Fuepr^a oJo^\ eq EiJe^ qtr,1d.puB rq8[u 1?q1Suq ue Jo ecuosqeeql sr Suqz seues qd pu" aql Jo stueuoduroJ lJal puE "d t puoses eqJ -znd eJour ua^a snlEledde eql qlr^,\ palercos tqAIJ oqJ ,{lerluo^oJelu? popeJrp sur8reur 'proJeJ -s? oJnleln3snu Jo uoq?crpur ou sr 3J0ql pu? olelnsuuep rraql qlh\ pelueuo ele,,ll snlEJedde Pue suro,{l"u 'el?ld lEspq ? urElar ol sJEedd" snl"JpddE eql clleqdec eql uI slue(uele seues pue eql ,eldruexa .slallelu Jo S I I lFus^ur epur ur sl.uelueleeql Jo ouou JoJ 1"q1 ,tle{rt suees 1r ueql 'eq lqtrur lr pelse88ns crurol?u? Jeqlo pedsel I ele 'esJnoc I?JeAasol qlp\ olnur (€861) T te s33pg s? 'ug lEsrop e st lln oqtJo EquEuro qsrl ,(IeleunuoJun sr lr 'oqol cll€qd33 ogl uqtr,'(, urAJ€urauo Suop elnlouls peuoddns-,{?JeqlJr snl?Jedde aql !a iq pelrqrqxa Jo uorleluauo pu? uoUpnlrs pue 'ftleurl'u,(s lerolElrqJo eu€ld slr 01 leller?d d'uorsseJduoc ql elnjrue^rP plq,d'eunsalur .pu'rocsroeuo*pues uoru'ro t aff (t'8 8rC) upnueur(rau,",..0;9ot_gtJJl::."iff J;'ltX"P,":TJiffil#JJ:"Tr? H'Ii1t DqJu,{qU runl I 'uorssaJdurot ieli lq8tur leql IsproqJ lng Z firf) auul(W Drllo Jo pue uuo lsorqJuDtg ia{DJo lueJslur IOJO Uorl?nlrs aF eqJ lunrl IXrJtxa 01 uaes srr eqr'(9861) 6g 3rg) sueu aql uI lulul qlroJ eJ? pue ar? saJnpnJls bg) ueurDeds . q ,{lloualu? InJo saprseql rf,s 's3Jnpruls I SuDluts lsour t p o.t\lJo eiuep olalsrsusrrr D {unll aql

VJNOOONOJ IIHJ 0t WHOLE.ANIMALANATOMY ll

The trunk of all four of the Scottishspeci- requirethat all segmentsofthe axial structure mensis 1.2to 1.8mm wideand preserves evi- in everyspecimen represent the sameorgan or \ _\.aA denceoftwo distinctiveanatomic features. The organsystem. For most ofits lengthin all ofthe .'. , most striking consistsof a seriesof V-shaped Scottish specimensthat show it clearly, the structures,which were apparentlysituated on axial structurejoins the apicesofthe V-shaped 4/ _r' thesides of theanimal and whoseapices point structuresofthe trunk. No suchrelationship is anteriorly. In the most completelypresewed shownin the anteriormostpart of the trunk of specimen(Briges et al., 1983;Fig. 3.1) these the best-preservedspecimen (Briggs et al., structures are rather indifferently preserved 1983;Fig. 3.1),however, and the axial structure and are confinedto the posteriorhalf of the in that specimenmay not be continuouswith, trunk. In the three more fragmentaryspeci- or represent,the sameanatomic feature, as the mens (Fig. 3.2) describedby Aldridge et al. discontinuouspair of axial lines in the poste- (1986),the V's arebetter preserved and may be rior half of the trunk. Aldridge er al. (1986), seento extendnearly to the anteriorend ofthe who allowedtheir interpretationofthe Scottish trunk. The shape,serial repetition, and lateral specimensas primitiye chordatesto restrict >-. \ situationofthese V-shapedstructures are rem- their survey of anatomic possibilities,suggest iniscentofthe myotomes(or muscleblocks) of that the double lines in the anterior parts of hP;r. Branchiostoma(or "amphioxus") (Fig. 8.1) severalspecimens might representsome parts I ol .e.t.tu. and of other chordatessuch as the hagfish or all of a nerve chord, notochord,or dorsal Myxine (FtE.8.2). aorta.I suggestthat one might alsoconsider in- But chordalesare not the only organisms terpretingthis pair of lines as the incomplete thatmight yield such V-shaped impressions on trace of a nemertinerhynchocoel, the tubular compression.For example,nemertines (phy- cavity within which living representativesof lum Rhynchocoela)such as Nectonemertesthe curious group of invertebratesstore their k::. of Scotland. (Fig. 8.1) are characterizedby a long, straight eversibleproboscis. Such an interpretation,of intestine,which bearsnumerous paired lateral course,would not rule out interpretingaxial diverticula that might, on flattening and lines in more posteriorparts of the trunk as compression,produce patterns similar to those traces of a gut with numerous lateral d =e apparatus exhibitedby various parts of the severalScot- diverticula. t i ';nfonunately tish Dinantian conodonts. Nemertines, of If the axial structurein the posteriorpart of I o-rhrr anatomic course, are pseudometamericbut acoelo- the lrunk of the Scottishsflecimens is inter- J:!e elements in mate invertebrates,probably derived from pretedas a gut, it appearsto have extendedto tr a basal plate, flatworms and not known to have a fossil the posteriorextremity of the tail in the two f E::sculature as- record. specimensthat retain it (Figs. 3.1 and 3.2). ! Er:r more puz- The secondfeature recorded in variousways That would mean that theseanimals lacked a ig rhar might be and with varyingfidelity in the trunk of all four postanalsegment, or true tail, featuresthat are fr :-.rrrcture com- Scottishspecimens consisls of a line.or a pair characteristicnot only of chordatesbut of in- d :-ae hagfishes, of subparallellines, more or less coincident dividuals in virtually all the deuterostome r Fbst|ate for the with the longitudinalaxis ofthe body and ex- phyla. On the other hand, if one assumesa r d- a@chment of tendingfrom a point just behind the cephalic nemertinemodel, even with tonguein cheek, I (onplex appara- lobe on the anteriorto the posteriorend ofthe the problemvanishes. for in that g.roup-as in mens provide no body. Aldridge er al. (1986) note rhat these most invertebrateswith a completedigestive ! r-olodont appa- lines might representa number of different tract-the anal end of the digestivetube is sit- qrrielium or ex- structures.For example,they might be tracesof uatedat the posteriorextremity of the body. I Her elements of a notochord,a nerve chord, the gut, a major agreewith Aldridgeet al. (1986)tbat anatomic I eld might thus longitudinal blood vessel,or a mesenteryor interpretation of the axial structuresof the I b.'5 or whether septumdividing the body cavity into compart- Scottishspecimens is inconclusive;however, I I tt':s may have ments.I agreethat a gut is the anatomicfeature suggestthat, in combination with other fea- rsi. supports for mosl likely to be representedby most of the tures,those structures might well tum out to be Lc in a buccal lengthof the axial lines in most specimens.as significantin reconstructingdetails of cono- However,evidence available thus far doesnot dont soft anatomyas the V-shapedstructures I |nOpSI^\IeUOn 'suolrlrcedsqs$locs oql 'Ja) snplsurun snPoDpuod ol elqeleJeJ sI tnq esJeds pesoduoc l -iEtu Jo crlsueper?qtuJollsd ped?qs- oqlJo uorlec IErrnu" eq1 eleclpul l?ql slueruole Jo IJPrAe Sunsrxg qJrq,|d. -rpurou srorJqJ lurul JqlJo srxE6uol aq1 ol sr'peuuoJep uoeq lou s?q eql ^IlueJedde'^poq oql su"d iJErutur|S t'€ esre^sueJl pu? lqErcIs eJEsouepunoq 'snl?JBddE lelelqs Jo puE lueutes elqrssod^lperrp s3 PeloJtuelul saul luI"J Uos oql Jo se3"I pe^raseJd ,(leleldluoJul 'uou"luelu slueuele UIJoJ eqt '(/86I ) I? le qlrurs polou sV ,(IluareJrpur qlr,$ uoDercoss" ur ^q uoweu{ esJo^suell -ruo3 snlEl?dde elelduoc lsourl? ue sopnlc r-Irorl?zlpJeurul -tes l?u€uo slsetllns 1?ql Jo (€'t 8IJ) ueurlseds eltuls 3 sI ?lorq '-- € lUeSeJdeJ 'onte^ uEql rerllo snp$oJlun snpolapuDd -ur lew Jsqlo slueuodrxoc eql Euoluv 'ulsuocsll r -itJFqrssod eql Jo ,turoleu? ipoq-uos oq1uo uorl?ruJoJur lerD Jo uopu?Jg u?u ns perrrJoJ 0^"q alDrl fue^ sepr^oJdueurlcods oql '?qse)lml|{i Jo uo4euloc aEpug 'sluaullpos"r{so{nEl\tulsolcue eql eq1 luo{ sleuruB pelPoq-gos fllusunuop B irrlrqrssod eql Jo -nlrs u" slueu l rc spodoqrsrq uorpsdr[oc uo ,1?,!\lusJeJlp fua-/!e uI peuloJ Jo Elorq pe^Jeserd ,( ?uoudecxe Jo pequcsop yoPuossenl) pue 's6Bug roJ lEql elrl -ap ueeqe^eq plnor\ snleJ?ddueql (suosrcods -odrljoo ur perEedd" sred?d o,{u uI o luopouoJ pezl snoreJruoqJ?cqsqloJs eql qlrt\ es€c eql ueeq 'oIn)III I'9861 lBqt pesseldruot ,(lleJelel ueeq t oe .{eql ,. el4.t e eq 01 sJeaddssD) uaurlrads sqsa{nEl\ aql Z'€ 'pessoJduroc qrl$ ueSelloc Jo 1l peH oq ElnlleJ ur 'Jo s?^\ eql l?ql slsaSitns^ll?Jlue^osJopsnl"ndde ^Ueul8uo pe^les ^poq uou? 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'uql ? s? pe^res eqt epnlcur suerurcedsqsplocs 3ql Joi,![tE '8uol €qsal lpelEIeJ ele 'sleu - d sr uru tt lnoqesI uaurlJeds Saoeds -ns^\ eql {f86t 'eEpFplVpu" 's8ilug 'qllurs lunoluel"d pl?d o^"q ol ur00s qJrq^l ol Imueqds ^eql 4{ 'e?ururn'I ) .iFuoJls ? a^erl rc 'JelleuJs eft {/861 'pu€l3ug'rerserlcqC ' pl.I poo^uoHsrllg glaurIp Suol puE poqslqnd'(po 'o8pup!v) stuopouo) Jo [Solorqorrlrdtuo{ uolsslulodqlr^r pocnpoldox ulsuocsl^\ 'Etlsolne^\ ^ql? itot-riuirog uopuergueunls eql uro{ sntD$onunsnpoapuod Jo uoulcadspaAroserd A eruedv '€'€ '3!d :afuel fla^rl?ler "ipug q sod& snouE^ 3 JO SUoUJTCOdS d Jql uro+ pe^u deJas ur sedEqs pJ .(luEd ts?ol lE .s[e] t Peg4uepl { pu? sne?rrBc F i8olotslH €'€

VINOCIONOJ AHJ WHOLE.ANIMALANATOMY

3.3 HistologJof DemineralizedTissue soft-bodiedanimals with a slender,vermiforrn body a couple of inches Fdhraeusand Fahraeus-vanRee (1987) have long that may have beeneither laterally compressed identifiedcells, fibrous material (thou8htto be or dorsoven- trally depressed. at leastpartly collagen),and luminaeofvarious The anterior end of the slen- der,elongate body is shapesin scrapsof demineralizedtissue de- developedas a distinctce- phalic lobe in known rived from the pectiniformelements ofSilurian Silurian and Dinantian specimens and includes specimens of Ozarkodina confluens. Cells of the apparatus of mineralizedelements vanous types have been identified; some are by which conodontsare bestknown. The slendertrunk is divided into i F^ire Formation relatively large,with nuclei 3 to 5 pm across serially repeated transverse structures ft=:,:'. published and long dimensionsas much as 20 pm: others that occur on either side are smaller, contain numerous nucleoli, and of or surround an axial structure havea stronglyeosinophilic cytoplasm. that may representthe gut, a noto- chord, Luminae, which have the form of irregular a doral aorta,a longitudinalseptum or mesentery,or some 19f,-,, The Wau- spherical spaces,and single and branching ca- combinationof thesestruc- tures. The transversestructures, which are V G -One-rs pre- nals,are related by Fihraeusand Fihraeus-van shapedin Carboniferous (but lrile bmken edge Ree to the irregular frothy spaceswithin cono- specimens not in the Silurian one)have trG atrd repre- dont elements that have been termed white beencompared with the myotomes (or muscle E E:anor part of matter. Flbrous matter is sparsely distributed blocks) of amphioxus and fish and thus ;fu,.v,a eriginal among cells, occurs in bundles and, for the taken as evidenceof body segmentation. most part, lacks nuclei. Some is dense,baso- Thoseinterpretations are not re- quired, however,and frte .-tphalic ap- philic, and apparently associatedwith elon- the transversestructures mightjust aswell represent paired ilceg anestrans- gatedsinuous cells. The fibrousmatter without the digestive diverticula ll r::.k and with nuclei is consideredto be collagen.Fihraeus that characterizemany acoelomate nemertrneworms and, as such,indicate only lE--ror- Smith, and Fihraeus-vanRee emphasize the fact that pseudometarnerism.The posterior lllat this onty 20 to 25 percentof the tissuefragments end of two of the flve known t a5trafillus was they studied is collagen,whereas collagen ac- whole-bodiedfossil con- -esl odonts is qE\ls.d halyes, countsfor the entirematrix ofmost othertypes bluntly aciculate,and its margin bearstraces of ray-supported ds longitudinal of mineralizedtissue. They also point out that finlike structures on oneor both t iobe and the the largenumber ofcells in demineralizedcon- sides.Linear axial structuresex- tend to the posteriormargin &55a specimen odont tissueindicates that it ". . . is not bone in bolh specimens. Ifthese represenl gut, rai ro rhe plane or dental tissueas we know it," becausebone tracesofthe the Carbon- iferousconodonts may not have postanal lEr1le. consider- ". . . is eithertotally non-cellularwith an extra- had a segment,or true tail. in the pre- cellularmatrix largelyconsisting ofcollagen . . . The five whole-bodied I--'.5 .:hr My was or, in cellularbone, it is dominatedby bundles fossilconodonts now known raisealmost as many questionsas they trcssed Had it ofcollagenwith the occasional'trapped' osteo- provide answers.It is a comfort to know that r +ears to have cyte." They go on to statethat the demineral- the skeletalapparatus I Carboniferous ized conodonttissue of their study is also un- is apparentlyassociated with t ba..e been de- like that found in living inarticulate the cephaliclobe, for most ofus had con- cluded from oo compaction brachiopodsor mollusks.They do not exclude seat-of-the-pantsfunctional anal- |l ysis the possibilitythat primitive vertebratesmight that this would turn out to be the case many yearsbefore lFiles sery little haveformed suchtissues, nor do they fule out the famousScottish speci- mens were lo$ aaatomy of the possibility that the tissuesthey studied discovered.It is also no surprise that the specimensindicate E Lbar vague, represent a ".. . unique approach to bio- an elongate,ver- miform shape,since that is a shapecommon to lrss original seg- mineralization." mobileaquatic lcr aI { 1987),the animals.However, even though the skeletal pible segment assemblagesincluded in the whole- bodiedfossils lecrlr ransverse 3.4 Summary seemto have beenonly slightly distorted There is no indi- by compression,they all apparently Existingevidence on whole-animalanatomy is lack basalbodies, possible I (ia.racreris tic of and it is not to de- sparsebut may be takento confirmthe conven- termine how they may have been related to tional wisdom that conodontswere prirnarilv muscularsystems or whetherthey were com- 'ruloJ I [" 'serceds9s rxr pu? eldurrs) I I paurEupuB gorlv 'o{q eqr EJ?qC 'SoSSoC Du3Sq? rO oCUS I qJns seJnlEeJ fuJeJ eq qorq/'{ E-raJrp ,(lsnoh FIIOJ S.Jopu?d mJ"AaJ sdnoJ8 I uo peplrpqns na8 se pour?u rJoeetec / olul lE pr^rp raqunJ E eql '@u|oz druoJ,, peuu3l ! pue uuoJrur?J ldurs,, peurel loJ srq ur slueur nrt ur8eq oI rgaotod JeqlEJ qolq Jo uou?cg rruJla lenpl^lp tsPIJ ueu?lr[ln poq aues eql ut 'd 'dd 08t 'relsoqcqC 'poo^uoH sr[a (eSPTrptV O8I 're$eqclqJ puorx JrSoloqd 'f 'U pa) stuopouoJ lo [SopqoaDlDd vr bll 'poo.rroH sUA (o8plrplv f )d'p.) siuopouoJ trE Jo uoncuru -16 sluopouoc pltuopoJepu?dJo ernlsellqJJ? Io tSoptqoaDp{ ul 0l I-90t (uEUntIS'eluopo J:tfrrsue01 oIqE snlercdde aql pue 'VSn 'ursuocsld\ Jo u€unl -uoJ) saanlluoJ D apoap?ra Jo slusurele uuoJl (t861) peurJl€crpJoxuleru enssll (/861) me6qE eql uI -rs Je,rol eql uro{ lErurueruopouoJ v -urlJad UoS 'f d'e8pupN pu? ''D g q 's8:lug 'd 'I^t 'tIlItuS 'g C 'eeU ue,^.-sneerq?Cpu? "g 'I 'sneeJqEC 'dd ' t3 op aD erqr,Jl]loJ aqt puEeuo 16'Srnqsn@d 1S ZZZ-6 6 t' 6l tao P d' lJqres 'slueweure^noo alBroqdoqd p Dqleq^rro :selc 'ss!,,ll ptDlv l8tuox ueqtsrl qsrlug Jo eleqs sss8rng aqt uro{ Jopsurols,(S ueqosunls sepeqtslJ -oJ u?uqrueC V (9161) S 'slrrot{ ,t?/ruoC t-rrJsrsEqluerJluns 1Eq-qcs$sru ^leu :on8uoleql uelssoJ rop eqd€rSouo} I (9S81) H J 'repuEd vl Taq.$ 'dd 'leutruE eqJ (t86 DFq .(eql Jeqloq.{ 08I 'relsoqJrqC'poo,$roH srlla -l 'gl DrDqpT tuopouo, I ) f suopouo) l6optqoa0l 'd 'o8plrplv puE 'uos{relJ ''C a ( 's?ilug F ldou)l l.uop ey'A leSplrplv t d'pe) lo ) N'E 't6z -oJ uI06-LL IErurUeluopouoc eql ur luetllele pue ocIN olwllaI 'pueqocs, :(uorlelsuuJl ?d oqlJo uotpunJ urod 086I)'S'U' -6LZ '$)6t 'qarnqurpgJo 's8-8r'II€ 'g'res'uopuoT ')os snoreJruoqJESegl uo{ ecuePrlo Eoxsl $roqc ^lou-sluopo Jo 'toy suDtJ Tl4d 'vsn 'u$uocslld Jo u?un -uocJosenrulg€ oql (986I)'d'I I'qlllus puE pellser^\ {q ur lrs Ja,$q-I aql uo{ ?lolq pe^.lsseJdflpuoqdec '111.1g'uos1:e13 "C A C 's33ug'f U 'eBPgptV |Ixrp oq^\ 'Jop -xo A{ouV (q9861) - Pu€ '-'- ' aruaps soJuoreJau I I 'I reld?qJ uI Lt L-gt L '8ZZ 'Etorq perpoq-UosuEunlrs V (es86l) 'f Fop pue 'O IEI utrotr I't -uessonl){ 'C A (I 's8ilpq 'C 'cltnllhl 'eluopouoJ 'dd 962'tlt ndod 2ads 'utv JoS 'paD (sepoqu I lH'Ji pe) l8olooz eql Jo uo4rsod srt"uels^s aql ol padsoJ ealDd tuopouoJ ur 99-lf 'eu?luol^l 'Juolseur-l qll{\ suorsnlsuoJ uo f,DteJlpur pu? snl?Jedd? qclnc JBsg sql uro{ sleulruE iuumq-luopo Jrt?qdaleql uo[lJunJJLll suonEleJdJelul (€t6I) 't|H pue "C 'uoltew Jo Jo '' -uoC 'ttoc5 A\ Jno uo a8urdur srellprueseql ',(lI NOXVJ 'ezl-lol 'v 0!?qp7 sluroJr?lluls V ^OcoJrp sFlcod uI pele w pup edft D apoapng Jo sesntBrpddeluopo -A?cleccnq eql uqtrli{ Ieleqllde -uoc ur lueue8uru? lueluelg (lt6l) "I 'uossddef -nlrs Jo unlequde lBccnq uI pasolcue ,{leleld

VJNOCONOC EHJ- lGment rn con- *-1 t-rpe and in -l:1. l. r 1973).Con- 4. TAXONOMY I tt Bear Gulch aC...'-dont Paleo- I G;,-'i. Soc.Am.

G- a-ld Kluessen- 4.1 FormTa-xonomy Pander'sclassification ofconodonts was pro- f"j-rcdred biota. posedlargely as a meansof giving order to the In Chapterl, I pointedout that ChristianPan- systematicdescription of specimensin his col- aib,- A new ex- der, who discoveredand named conodonts. lections.He made no attempt to give it pro- r -3e Lower Sil- wrestled in his 1856 monograph with the fu- Tens. Roy. found biologicmeaning, nor did he useit asthe choiceoftaxonomic base.He wrote (my rough $, basisfor discussingeyolutionary development translation): h-uon of the Pa or addressingother biologic questions.Evi- d ---90 in Pa- L R- J, .{dridge). We don't know what sort of teeth we have before us; dently the classificationwas to serveonly until lre- wheth€r they belongto the jaws, the palale, the lips or discoveryof more completespecimens made it particular ;le der fossilen the tongue; whether each shape conslitutes possibleto determineif all elementswere mor- genus r&r russisch-bal- sufficientbasis for establishmenlofits own or spe- phologicallyalike in the body of a singleindi. +t .t\rd. Wiss., cies; or whether different forms could have come from one and the samebody. vidual, or if the body of the sameindividual d t"lridge, R. J. might havehad an arrayofmorphologically dif- h te lower Si- In the absenceof a living analogue,and un- ferentelements within it. d --:e apparatus able to answerthe questionshe raised about Although Harley, Smith, Hinde, and Had- I csqodonts. 9l- function or anatomic position or about mor- ding contributed to conodont taxonomy be- (ed. E-{-r R. J. phologic monotony or yariability of elements tween1856 and 1926by describingdiscrete ele- bssrer- 180pp. in the samebody, Panderchose an admittedly ments of distinctive shapes as genera, no utilitarian classificationbased on shapeof in- further consideration of suprageneric catego- dividual elements.This approachto the classi- ries seemsto havebeen made until 1926,when fication of biotic groupsis sometimestermed, Ulrich and Basslerpublished their influential rather pejoratively,form taxonomy. taxonomicscheme. As you will recallfrom ear- To beginwith, Panderassigned coniform ele- lier discussionsin this book, Ulrich and Bassler mentsin his collectionsto an informal category stated their firm conclusion that conodonts termed "simple teeth" (Einfache Zahne), and representednot only the teeth,but alsothe der- ramiform andpectiniform elements to another, mal platesof extinct groupsof fishes.In addi- termed "compositeteeth" (Zusammengesel.ztetion, and probablyrnore significantly, they also Zahne). The s.impleteeth (Fig. a.1) were then concludedfrom their studiesof recent fishes further divided on the basis of crosssection, that, exceptfor the fact that they may occuras into 7 categories,which Panderdescribed and right and left mernbersofa pair, all teethin the named as genera.Finally, each of these was mouth of the supposedliving relativesof the subdividedon the basisof cuspcurvature into conodonts are essentially alike. Thus they groupsregarded as species.Composite teeth in wrote ". . . eachkind is characteristicof some Pander'scollections were represented by 7 ob- particular genusand species."In short, they viouslydifferent mophologic categories. among professedcomplete coDfidence that a classifi- which he recognized18 specieson the basisof cationbased on the shapeofdiscrete elements, featuressuch as mode of denticulation,pres- a form taxonomy,was a true expressionofbio- enceor absenceof carinae,angle between pro- logic relationships. cesses,character of platform extensions,and In their 1926 paper Ulrich and Basslerig- the like. Altogether,then, Pander recognized nored the one genus(Periodon) proposed by and named 7 generain each major category Haddingin 1913,but distributedall the others (simpleand compositeteeth) and, collectively, known at that time, and 15 new ones,among 4 56 species,all basedon an analysisofshape, or supragenericcategories described and named form. as families. Pander's"simple teeth" category FP \rOU SlUeIrJ ecEJ?rdolur lnd 1ouse^{ lnq Jepu?d -uud Jo reprolcuqxo uE sE sluopouoo er{l poug r uI pel?rlsnlll -sod ? s" pezruEocaloslE s?,^^,\',{urouoxel ^q ^lrTqrs uuoJ -epIqoIAI pu? uosu"rg tt6l ur lnq '(eprqaue^ F lou q8noq1 01 e/\rlsruelle ue '^uouox?l luouraleqFl^tr unl,tr{d 'sacsrdssep eql Jo) IluopouoC ss?13 EUO.\eO 'UErJq -qns aql ur sluopouocpapnlcul uosuerg 8€6I luauolalflntrtr Z't 'luoserder ,{eqlsorceds pu? Jo ,.seSElqures ^utouoxsl uI ol lq8noql eJoa\ E eJe eJeqJ eJeueteql Eurueu puE SursougElppu? slueur rxrpurg Jo sJr"d '(ralss?gPu? qcu -ele luopouoc Jo sed^t u,,l\ou)lun rEoud Jo rred {nJo 1?q1ur t lo auleqcss.lqel l pu? uosueJg turqucsep ol suorluoll? Jreql^lsnol^eJd peto^ap tprporuoud Jo ul g qll { pereduoc) /I paFlol sseH pezru IqeII Pue uosuerg^leBJBI t?61 pue €[6J uee,4Aleg rD plno^\ I?rJol -BooeJsouotel€J cueue8BJdnsJo Jequrnu^q eql 'qleel lou 'seleld puuap se polortuelur lDq E qsns q1v( leql ossJrFueJqns olur p:pl^rP aJe^l(sPplluop eJend qcrq^\ 'sluaruele uJoJrurped pouJJoJ rpur 33u3J1s eq -oqlEuSoPIPue'e?pnuoporuoud'o?pquopoel -lEld uo paseqsercods pu" ?Joue8llE pePnlc ruBrg 01)palld -oJ) seqrur"J3erql 'pu?q Jsqlo eql uo 'sJopJo -uI rellEl eql :sedegssnolr"^ Jo sluelualeruJoJ IrnJeds s.llocs -qnsssoqt ozrutocar lou pIP flluenbesuoroq,r -ruDcod ssoluiroJl?ld pue stuaulele urJoJIueJ 'J nIEl8 I pu? 'ss?I{,{q luelsrxeuouJo luEcUIuErsuIsE pap$8 roJ PelceJeeJe,ld esaquo o./irllsJgeql 'aeprqlBu .stuopouoc [3n -er ar3,r1sau oJrluopouoJ pu? sourJoJrluop -t{Iod puE'e?prurpououd'(ezplluoporuoud t sE PeleJdJolur -ornoN sJopJoqnsaql ezuSoteJo1 pesn HeI I :01c0J)oeplpoluoud serlrureJ3q1 olul popr^rp E aql Pu? 1no pue uosueJg1?q1 oJnpruls l?uJelur Jo seJnl?aJ seAtfuo8el?r ..q1oalolrsoduroc,, sq pue '(o?p ilBqJ 'uoursod eql 'serlurEJI olur pepr^rPse,r qJtq,t (ept -rluopooetsr(IueJq o^?rl plnor{s qJtq^l) e?pt ruDeds IeJo^as -JoqdotuopouoJaql) repJo ol8urs? ol pouS$ -poo"tsrc eql se peguuepl f euJoJ se^\ ^truEJ aFolc sr se8elq -seoJeA\ sluopouos Jo eJeve?Lvl 'ssEHuaqlllA lo uorlrsoduot lsolup uollrJ \ 'eunlo^ puosJed oJo sad^l oulEs ^q ^leJrlue '2961 peJP.edde ,(lq8q t"ql uI ul \3{t4u\'{8opj 'suorlcesssoJc gql lq8u oqr ol seuqi^Eoq oql SuolB r a8P eurEs oq1 Jo -uoal0d aptqaua^uJ uo astloatJ oqlJo A\ arlrn seulllno pJelq ur u,roqs eJ€ pu€ dsnt oql Jo eJnle^ 5q1 n+ IIe ar? stsl8o 1oA ur errroeslr paqceeJ{loJns slueujele eleJc -rnc uo poseqeJe \ sorcodsslolcelEqc cueuo8 Jofeul ftlqr.uass? oql sepcrpureull lEluozuoq qtuoJo Pue 0q1le uollcosssolc -srp 'pnpr^rpur Jo sedeqseql Jo srs?qeqt uo aqf sorcedspuE ereue8euoc-oldtuls s.ropusd 'I't '3!d l{ Iq puE i(uPu sluoPouocJo uorlssgrsselJIeclueqseru eql ?f6l ur ureql pauroJ EsIa Jo ,.sotulq^FueP lEql qsg eqlJo eqt pedselce^?q ot lqEnoqt ^{?f sroru 'Jeqlo oref\ qcrqnd 'saprsrepun ellqSnol 'deap n4 etu?c slueur ,{le^n?lal qtl/( slueluole snoJqg EOJ lOU S?,!1eq ,{q procer lrssoJeql ur peluasardal er"^ll?ulalul 'oldrue uI e ur pesouS? -xo roJ 'a"pquopoeloCeql ol pou8lssesJeue8 qJ aq auEu aql eorqt eql eluoq ueeq a^?q ol tqAnoql are^\ aBcrpur 01 qels .{eql qcrq.{ uo rruer ,nef eql. pu? r{teol ped?qs I toot aH oleqs ,(Fnou€^ eql uee,{rleq dqsuon?leJ pesod pJsodxe r /{lued -dnseql Jo srsBqoqt uo serlrrJeJs? peuuap sou I mrqnp snqtou -o8elecolur pednoJ8eral,|^ lv6l ur uaou{ seuo lEouoxel lueru ped?qs eql 'qleet qsg eq ol (6t8r) aputH lq8noql^FuereJrp oJo,t\sluauele ^u"ru luopouoc osnmeg'aJnl EueJrP ,tII?cI8ol -cruls I3UJ91Urrc errrEl E e^?q leql sluour rprq^r 'uolola{s -elef,q peluesaJdeJ eJ" qcrq,t\'EJeueA SuIurzI[oJ 'iSolEuP lde uV aql roJ peqsrTqElsese,l^ sor[JoJrluopouoJ rep oq eql ur reqleS -Joqnsgql seoJeq^\'ornloruls l?uJolul snorqu € r aq .{lqeuos?er (e^pq01 tq8noqt eJeA\ Jo) e^Eq slual'uolo esogr( Extral3Jo dnoJ8 €Jauetuercr^oplo €T pepnlcurseuroJrluopoJ fl 'iBoloqtuoru -neN JopJoqnseqJ 'eJnlcrulspuJotrur uI Jeiurp IrEd snoJournu sluetusleesoq^\ sluopouos JoJ peqslq€l$ eJo^t ["JEdde lelelo{s (seuuoJrluopouoC pue sauroJlluopoJneN) JuJrualan[nrrr,, srepJoqnso,!u eql 'sJePJoqnsz pu? sellltrr"J o 3ql rxo+ selc g o1.urpelquresse ere,$ qcq^\ 'eJeueB€, pequos ql$ 6/8I lllun -ep pu? 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VJ,NOOONOJ lHl- 9t TAXONOMY 37 lridia) and de- until 1879,when Hinde employedit for a spe- and an essentiallycomplete "natural assem- :sembled into 8 cies from the Devonian of New York. In the blage" is preservedin the headof the Scottish : tgo suborders "multielement" way of looking at things, the "conodont animal" discussedin defail in hodontiformes) skeletalapparatus ofa conodontis madeup of Chapter 3. So, since at least 1934,there has irhose elements numerous parts, not necessarilyall alike in beenno good reasonto defenda form taxon- h srborder Neu- morphology.The basefor taxonornyis thus a omy for conodontsas a natural one.The prac- E \-rcian genera group of elementsthat can be shown,or can tice persistedthrough 1962,I suspect,because rlought to have) reasonablybe inferred, to have occurredto- most studentsof conodontswer€ more con- bas the subor- getherin the body of an individual conodont. cernedwith biostratigraphicapplications than Eilshed for the An apt analogy,ofcourse, is with the vertebrate with biologictaxonomy. lresented by ele- skeleton,which consistsofnumerous morpho- f irEmal struc- logicallydifferent parts. Eere 4.2.I Multielement G thought Hinde (1879),the first to practicemultiele- methodology Erendl' shaped ment taxonomy, based his concept of Polyg- The major difficulty with putting a general r|rd ioro catego- nathus dubius on an assortmentof elements schemeof multielementtaxonomy into prac- )bsrs of lhe sup- partly exposedon the surfaceof a slabof black tice for conodontshas been the fact that "nat- r tle variously shale.He took physicalproximity on the shale ural assemblages"and fused clustersare rela- i on x'hich they slab to indicate original association,although tiyely rare and are not uniformly distributed bn<. The three the namehe chosefor the first speciesto be di- stratigraphically,whereas the collectionsavail- fu:dae. for ex- agnosedin a multielementsense suggests that ableto most systematicistsare jumbled assort- ! hsil record by he was not completelyconvinced that all ele- ments of elementsthat may have been com- rirh relatively mentscame from the sameindividual. ponents of several different multielement I rllich were Other, more convincing "natural assem- apparaluses.Thus, except for speciesrepre- roirhe fish that blages" of elementswere describedindepen- sentedby natural assemblages,a meansmust dently in 1934by Hermann Schmidt in Ger- be devisedfor determiningwhich elementsin i oi conodonts many and by Harold Scottin the United States. collectionsof discretespecimens were origi- J irdiridual, dis- The assemblagesavailable to thosepaleontol- nally associatedin the sameskeletons. lfu a,,-mein Vol- ogistsare all from Carboniferousrocks ofabout Perhapsthe most instructiveway of recon- at*ate Paleon- the same age and are made up of about the structingthe skeletalapparatuses of conodonts P- h rlat highly sametypes of conodontelements. Because the from largecollections of discreteelements is a rF entirely by compositionof Schmidt'sand Scott'sassem- basically empirical method. This procedure Ddouts were as- blagesis closelysimilar, and becauseeach had wasapplied as early as 1958by Huckriede,who C-onodontophor- severalspecimens of sirnilar or identicalcom- noted that in his collectionsof Triassic con- I r Iamrtres. lne position, chanceassociation was easily ruled odontscertain forms occurredmore or lessreg- h Branson and out, and the assemblageswere describedand ularly with certain others.From his observa- iorders Neuro- interpretedas the skeletalremains of individ- tion that certain types of ramiform elements hmes were re- ual conodonts.E. B. Bransonand Mehl (1936) wereregularly associated with one or the other Esrent by Hass, and C. C. Branson(1957) attempted to dismiss of the two most common platformedpectini- those sub- ![\ze Scott's specimensas coprolites,but Scott re- form elements,Huckriede proposedthat the rc ramilies (Co- plied (to Bransonand Mehl) that ". . . it would " Conodonten-Satz"(literally, conodont-set)of ,-d ldiognatho- be strangeindeed to find a group of animals Gondolella navicula (the platformed pecrini- tEmilies so that with sucha balanceddiet that the excretalma- form element)includes a pair of angulatepec- EL-sones recog- terial would consisttime after time ofone pair tiniform elements(refened, then Lo Ozarkodina *'ith 8 in ;nred of prioniodids,one pair of spathognaths,one tortilis), a\d ramiform elementsthat werein- r4 in that of Ut- pair of prioniodells,and approximatelyfour cludedin 1958in 9 form speciesassigned to 6 pairs ofhindeodells." form genera.Huckriede compared the associa- There are now more than 500 "natural as- tion he recognizedempirically with naturalas- sernblages"of conodontsknown from Cam- semblagesdescribed by Schmidt (1934, 1950) brian, Devonian,and Carboniferousrocks, al- and Rhodes(1952) and evidentlynoted agree- I ahernative to though not all have been described and ment in at leastmajor features.He appliedsim- pied as a pos- illustrated.In addition, fused clustersof ele- ilar reasoningto a reconstructionofthe ",Salz" rnto practice IEI ments now and then appearin acid residues, of Polygnathus tethydis, with results that are 'uetllrmds peluesardar = rtorv I Ct 3lq€J uI 5uo rsEetlE,tq eldu4s ul x fl-rour ur Apes:8 X XXXXXXXX 0l Eredde ptele{s X xxxxxxxx 6 XXX 8 |rr sad^l lueru XXXXXXXXXXX L DSUOJ lsn{rr e,\\ x XXXXXXX 9 : rJr 'esrnosJO XXXXXXXXX s , roJ lEqt eldrues XXXXXX X XXXXXXXX E F Jo qJ?a Jr lnq X xxxxxxxx z riu? ur JeqloSol X XX XXXXXXXXXXX I o,sl aqtJr '.{lsno st €I I I OI I soldues [oJJs eql sodIl lueurola F.sr J pue 'euop^luo saldwos ut sadlQ uon qu$Id, g'I{VJ, rrr Jequrnu eql 0I tuawala SI Io I t E rri.le eql rooq ql sI, q3rq,t uI eq lq8rur leql slueuala Jo 'sJalsnTcJo 'sdnoJa tsoru (^luenbesqns luelxe etuel ? 01 pu") 996I JO JJUJJnJJO-OJJO lUOlxJ Jql JO ldJJUOr e ot roud 'sr leql isepJrc luopouoc ur sleqllde olqa leql ur El?p ruo+ Surdole^op ur pelsoJolur aJ01Asorueu u,{ro reql l?ql PunoJ uoos lee,,irs Fg uo^ ,{q pesn eq plno^\ lsrurouoxsl luJuralenlntI.Ieqf'sald pu? rug4s8Jeg pue sraqalA 'ecrlcerd slqt 8ul 'sluellIele Fr 1?q1ur sod^l -urps0l ur sluJrr.rJlJluopouoJJo sedfl lueJ rp -ldop€ Jo sdnor8 lueuncal esaql ^g d [[P loJ stuercu s[ Jo ecueJJnccoeq1 sezrJerur]ns I't alqel {q paluaserdar sabads eqt JoJ 3sn ol se(ueu 3lq? rrIP^ JoBECueql 'urnuIIuIut se,+rEut1.to,r,r -lr?A? ,{ueu eqlJo qcq^\ SululuJelep UI pa,{\ol nE3Jq 'os :posn €J 1eql elecrpur seJnl"eJ esoq/,( slsoJ tuo{ {oJ era^r atnplluau.roN lnrSolooz lo salny prq^\ aul"s eql eJ? PUe Sr roJ erues eql Jo ,(ueru opnlsur leql louou?utaluJ oql pue 'selceds Jo se^Eeluas p eqr uro{ pe^u saldu€s Jo Jeqrunu e8Jel,{lq"uos€gJ ? qlr \ 8ur -ardeJ erll se peleoJl ,qll3rtdxe oJo.r\(resql€iA { aql pe^oldlue {?ep sr Jole8qse^ureqlJr, luo )lJo,{rsejnpef,ord Jo ..sasnlpndd?,, eqt 'epoF{.nH Jo a49S eql) j6l ) ued\o9rl/{ eseqt l?ql pufiu ur ldel eq pFoqs ll qtnoql pezruSooeJ,{aql sdnoJ8lueuncoJ eql 'Je^e^{oH 'stuopouoc pu? luqP Jo xepur 1€ '^e^ms Jeuq E quo,r ele senbruqcel tuuol uercr^opro reddn elppll I Jo {o){ r0qlou€ ro -snlJ :rfl Jo sJJnlp+ l?JJuaC sJrcedsesoql Jo suoncelloc egJEIJroqlJo srs,{lEu"c(uouoxsl ur F r{JeePuu 'son sosnl?Jeddeeql uI sluerueleJo sJr"d pue slueur rasql€d\ pu€ apeD[rnH pasn ^q p $r8ep aql 8ur -3le uea/$laq sollsl l?cueunu egl 01 se SUoIS pcurdure eur"s oql AllErluessepoqdd? ^Solopoqlaur (9961) 1^?q sluor3saoc -nlsuoc ouros qceoJ ol 'eJoruJequnJ 'puz serc lee,rs puE uro4sErog pu? (996I) sroqa^\ 'suual txlof, snorJ?l Jo -ods lueurelorllnur luenlDsuoc Jraql olul ssunq Srurouoxsl-IuJoJI"uouue,\uoc oJour lu 01pereprsuoc sarceJJo leDur,\oJd sE pepJ?EeJoq lqSFr lpq^{ ur poqrrtsop ejo^\ qd?lSouour srq epr^lpqns ol s3s?J auros ls?el lE ul Jlqrssod ur paJeprsuoc^l31€uIUIneq stuopouoc u?unlrs aql 'Je^e eu?ceq tr l?qt lFsoJ orn qlh\ '1oeA\SpuE urolls -aoH 'sercedsluopouoc .lEJnl?u, Jo suolelels qI r/otrt -8Jeg pue 'sraqa^\ 'resrll?l[ 'epeu)lcnH Jo spo olqeqord sql s? rueql pezuEoteJ pue SI -qleu Fcurduro aql JoJ seJnpacoJd IDcrueqcorrJ ,.sesu"Jedde,, sdnort asoql Peulsl ^lffelc3H 'sluopo NI polntrtsqns 'lceJe uI 'sercads tuopouoc -uoc u"unlrs Jo suoqcolloo etrq slq ur slueur tl sesnleftddE^eql eq1 s? pelep^o eq lq8ru] -ale sdnoJt lua[nJeJ azrutocat ol poqleur 7I Jo lelele{s Jo TI leql sdnoJB luorJnoer al?Iosr 01 slduIauz ur I?curdule eqt posn oslE (?96I) _reslll3,4A--^ OI slueuele eleJrsrpJo suorlcolloo otr?J ol 'sluelc Aepol slsruo 6 -Ueoc urs fueulq tuereJrp uo peseq 'spo -uox31 lsolu ,{q pe,(oldruo ouo eql sI oJnpeJoJd 8 L -qleur ^tu?Ituuelsnlc snouE^ peltdd€ e^etl (ZL6l) srql 'slepoul Jluroleue se pJ^ras leql sJaPtq 9 Jerllg uo^ pu" '(0/6I) u/(oullle,r Jr.ll sluJuodluoJ s 10e,'.\S'(6961) tnqo) -uosse leJnleu Jo ilsBotoql ol 'use qll,lr ,(lperlp peJeduro3 aq pFoc slequleul t ^3s t -rsnqluo rltr,r pel$Jt lou se,tr ,t('uouoxel posr^ esoq^{sdnoJt lueunceJ lcrulsuocer ol slusluals z -er sq1 ur sercedspu? eJouet ol perldd? sgrueu elarosrp Jo suoRcelloc e3ru1qlr,n fluellureJ slq -I eql Jo pu? eseq crurouox?l eql Jo uoIsIAeJ Jo Jsn JeJUrduJ Jpsrll 'uotls ut 'apJu{tnH I d(l Joferu E pu?-suralqoJd qdeJErl?lts e^[os ol 'sJoqlne leqlo t:navr os prp sluopouooporpnls oq,{\ slsrEololuoopd Jatelsl?a^ pelelsosoql ol Jelrurs,(lasols^q ^u?Iu VJNOOONOCAHI IAXONOMY 39 indonts did so TABLE 4.2. Jaccardcofficients for element-typepairs from Table4.1 r--ald a major Type 1 l0 11 12 13 14 t) bE ard of the I 56 61 10 18 33 56 J0 ?1 78 1t 57 56 7l lEries in the re- 2 22 11 40 44 29 22 11 80 44 80 60 22 80 H s-ith enthusi 3 -_ 88 ?0 60 7l t00 6't 33 18 33 38 00 33 -807063887844893850 88 44 5 -9050?08050905040 70 50 I ad voD Bitter 6 -4060?056805644 60 56 fusring meth- 7 1t 63 29 s6 33 29 7t 29 - iterily 6o"5- 8 -,:tr3 00 33 9 131333 67 30 hcrete elements l0 - 56 100 50 33 100 E groups that ll 56 44 78 56 I apparaluses of t2 -50 33 100 38 50 lql sp6511u1a4 l4 33 rf pincal meth- lf bers. atd Berg- i{ot? Decimal porntsomitted:"100" = 1.00;"50" = 0 50, e1c. I rhai it became E to subdivide tinsial or facies consideredto representthe skeletalapparatuses all possiblepairs ofthe 15element types whose tRlement spe- of various conodont species.Several different distribution is given in Table 4.1. Note that tl s.lme conclu- coefncientshave been developed for usein stat- valuesof thosecoemcients vary from a low of b hern een ele- ing the degreeofassociation between two enti- 0.22to a high of 1.00.What we needto do now llh apparatuses ties,and eachstudent has a preferencefor one is rearrangethe dataofTable 4.2 to revealclus- *s of the clus- or another.Kohut (1969),for example,used an ters of elementtypes more closelyrelated to LFt- survey, al- index of affinity developed by Fager and eachother than to other clusters.This may be rihl drat these McGowan (1963),whereas Von Bitter (1972) done in severalways. Kohut (1969)chose, in rs€ator is deal- employedthe Jaccardcoemcient. Clusters de- effect, to rearrangethe similarity-coefficient of samples rived from the dataofTable 4.1 are essentially matrix itself, as I have done in Table 4.3, by -erC ftrms and are the same whichever similarity coefiicient is rnovingthe highestvalues in eachrow and col- iicate rhat re- used; so, becausethey are easierto calculate umn to the diagonalmedian of the matrix. Von than Fagervalues, I havederived Jaccard coef- Bitter (1972),on the other hand, usedthe un- rgrrence of 15 ficientsfor all possiblepairs of the 15element weightedpair-group method to developa den- ELs in l0 sam- types in that table. The Jaccardcoefncient, as drogramthat graphicallydisplays the relation- nist $'ould be usedby Von Bitter, may be given as ship between pairs and clusters of pairs of h lr rhat table elementtypes. I havederived the dendrogram _a Dq-currence J=- of Fig. 4.2 from the similarity-coemcientdata of a+b+c b Ibar might be of Table4.2. in which a is the number of samplesin which In both the rearrangedmatrix of Table 4.3 both the elementtypes consideredoccur, D is and the dendrogramof Frg.4.2, note rhat there the numberjn which one of them is present arethree well-defined clusters ofelement types. alone,and c is the numberof samplesin which Two of theseclusters include six rnorphologi- only the secondelement type occurs.Obvi- cally different typesof elements,whereas one 14 :_i ously,ifthe two typesofelements do no1occur has only three. Furtbermore,both the rear- I togetherin any ofthe samplesavailable J : 0; ranged matrix and the dendrogram reveal the I x but if eachof the two is representedin every samethree clusters,which may appropriately samplethat containseither one of them,J = l. be identified as recutent groups. I Ofcourse, ifJ = I for a pair of elementtypes, In a multielement view of the conodont x we must considerthe possibilitythat thoseele- world recurrentgroups are the basisfor taxon- I \ ment types were originally parts of the same omy if their componentsalso exhibit several x \ skeletalapparatus, even though they may differ other important features.For example,if a re- \ greatlyin morphology. cunent groupis to be interpretedas the skeletal In Table4.2 I givethe Jaccardcoemcients for apparatusofa conodontspecies, one might rea- D illBuuesse -o rla '9161ocurs Ilr ro pelcnJls IOTIEIaI SSeSSe EFuss ? sepr^ DgEsgrsselcoql rursrp Jo suoll ilualJnroJ uro+ lsnlJ pesnJ Jo -ot bm: uaeqeaeq tr. sJaaot I a lt t 8 E tt 6 I 9 r tsql sarcsdsJo '€ elqEJJo xuleui peSuErrEeroql ur puE ereq aurrl aql rEeddEsjolsnlc orues oqf t€ql' eloN Z t elqeJ uro{ senls^ plecceJ sed^l lJo lv .2.t.3!d tuewoleJo sdnor8uoe^qeq suonel Surlndep ue$olpuop V Ftrau v t't

'suonenl$ leql le u^{oDI seEelquoss?I?Jnl?u eqt uro+ laJp s?^\ gcrq^\ uI uoBneo qtla pendde eq osp lsnur uoddns eulosqtv'i 'pepueluoc(696I) tm{o) ^u?ru '1S"O aruaqcs IcllspJe^ sIIt 'uoqs uI suTsulerlelolo{s Jrorll eql ur [rxap polnquluo3 3P pue Surrcl qorq.yrot sluour pelsrxe aAEqlqtru sulell"d Jaqlo teql fl$qls ue fJ?luerurpes^llBnlue^aeql ^aq1 ur Jo sercads eql ,(uep pFo,r 'posou8e -uoJr luopo -sod 'Je^e^{oq'sluopo Eo{ur ^lareu tul,,Jo ?leu93 -uoJ aurosJo {uoAoluoeql ur ibuulsuoc qcns -uoc IIE JoJuorlrsodujoj snleJEddEur ,&Fuepl peleJedo gJuelsrsur pelnqulsrpsarl lsuEte slue^e t"qt r?ep ,{l3urs?erJur uo qsr^els sluopouos JoJ slepoul oqdotuopouoJ euroceqsEq lr ecurs'sarcodsluopouoc eJo snleJ clluol?ue e^rpafqo AIuo eql sE sJDofiuEuj Jru1,, s? pr?8 -?ddeeqt s? dnoJElueunceJ e SunoJfuolurroJ roJ pa^res o^?q l?ql sot?Iques$ [EJnleueql g|Ilspurl p01r1ol uoueluc lereue8e s3 orleJ ro {ueJ uI asoql 01 tueudolo^ep IeJauetpu" requnu ^cu?lsuocplnoa 'per sselJelSurs loddns ol lInJSrp oq lr 'JoAoA\oH ur elqeredulocsluerueTe Jo u? opnlcurol Jo pe^uep ^?lJe oqlne asuDatJ -Pnlsaq spuol?uruBrcr^opJo eql rllo{ u,Yroqsaq u?3dnort lualnJer ?Jo sluguodrrjoc sretsnlcp ueseJdeJ-lseqaql IpJo eJnpeJ se^{ JI InJdIaqosp sr tI 'ezrsur aBu?JJEIrurs e pu? sEr\lnq 916l " .'P Iu?J ur ,{cu?lsuocluE grutrs lEql :flr^et 1eseqpu" ece3rnslueurqc?1e Jo lueur EII.I\.(I86I elalsuoulap puv^lForlsrl?ls 'sarJads utl uo asuDalJ ol alqpse^r oq luopo -dolo^epJo epolx pcpuepr ro JeFurs e :.,Jal -uocEJo snlH?dd? eqlJo sljed poJeprs -tEtII etrq^\,, uounqulsrp pue oJntdlnJsorc FLnE pedola^ I?tele{s Jo eq pc4uopr pue p (046I)^q urQrls -uof, 01JepJo ur ou?r ro {u?J ur Jeqloue euo -rur Jo Jelrur6 e :eJnpnJlsorcru ol drqsuortElarJBlntar ouos osl? pFoqs uollelncDuep ePou I?J[uePr Jo Jelrurs e rcuoxel eqJ ^\oqs Jo dnor8luolnceJ slueuodr.uoceql leql 'erull e.,\.?qol slueuole lueuodruoJ slr Fadxe ,(lqeuos ; a{lJo raqlou? "Jo E erJuoE€/ Jo ufl 'reqteSollv qlrusJ eql ele,{{ '.re '0S0 = ..01,,:00 I = <{00L,:pouuro ueeqa^Bq slulo

VINO(ONOJ 3HI 0t TAXONOMY 41

4.3 MultielementClassifications ment or redefinition ofcertain categorieseslab- lished in that volume. Personalprejudice dic- t5 l Ljndstrdm (1970)compiled the first classifica- tatesothers. Thus the classificationadopted in tion of conodonts that recognizedrecurrent this book and discussedin somedetail in Chap- i: rr groups of morphologicallydifferent element ter 5 wilt appear,at least superficially,to be typesas the basictaxonornic units. Conodonts 4r l3 quite different from that in the Treatise. Some 5r J-l were groupedinto 2 orders (Westergaardodi- brief commentis thus in order. _= t9 nida Lindstrtjm and ConodontophoridaEi- i: {0 First, I havebecome increasingly skeptical as chenberg),with the latter (the "conodonts =rJ to the amnitiesand relationshipsof proper") further divided into 8 superfarnilies the tiny, weakly phosphatizedfossils protocon- (Distacodontacea,Panderodontacea, Chirog- termed t_ rl odonts paraconodonts lumped nathacea, Prioniodinacea, Prioniodontacea, and and to- ES0 getherin the Treatiseas the order Paracono- ES0 Bryantodontacea,Gondolellacea, and Polyg- dontida. These superficially -so nathacea).These major groups were defined, conodontlike forms are quite different in internal structure insofar as possible,in mullielementterms, as from the onesdescribed in Chaprer2, for which werethe familiesinto which they weredivided. Bengtson(1976) has provided general Altogether,Lindstraim was able to assigna total the term "euconodont."Although Bengtsonhas shown of73 generamore or lessconfidently to one or how paraconodontsmight have evolyed from anotherofthe 2l familieshe recognized. lR-luTent group protoconodonts,neither he nor has The taxonomic schemeoutlined by Lind- anyoneelse r RiauoDship to yet documentedthe stepsby which eucono- strbm (1970)obviously influenced the one de- tcdsr ro be con- donts might have developedfrom paracono- velopedby authorsofrevised Volume W ofthe ;rarus of a con- donts. Szaniawski(1982), on the hand, Treatise on InvertebratePaleontology (Clatk et other !- demonstrate hasdemonstrated that conicalelements of one al., 1981),which waswritten betweenl97l and rca-nc1 in rank of the protoconodonts(Phakelodus tenuis) arc 1976but was not publisheduntil late 1981. Ried clusters essentiallyidentical in jntemal structure the Treatise atJlhots included alt conodonts in a to he stud- graspingspines of modern anow worms singleclass of a phylum Conodontaand fol- such -ialshJr to support as Sagitta. Thns, Phakelodus proto- lowed Lindstrdm in assigningthe animalsI re- tenuis, a ;wal criterion conodont,may well have beenan early repre- gard as "true conodonts" to one order (the F as rhe appa- sentativeof the phylum Chaetognatha Conodontophorida),which included 44 fami- or of p r: has become some now-extinctgroup closelyrelated to the liesdistributed among 9 superfamilies.The 179 lFaled against chaelognaths,and not a conodontat all. generaof "true conodonts"recognized were di- Sza- ;; oi some con- niawski(1987), whose careful histologic studies -rarl agnosed,insofar as possible,in multielement envrron- are certainlyimportant in this regard,contin- terms and described in the terminological l! contributed uesto hold that the proto-, para-,and schemedescribed in Chapter 2 of this book, eucono- + ihrs \ ardstick donts(i.e.. the Paraconodontida which was developed specially fot lhe Treatise. and Conodon- Ef,n rtr many tophorida of the Treatiseclassification) form parts of a singleevolutionary lineage. He does not regardthe Conodonta(in which he would 4.4 A RevisedMultielement Classification includethe Paraconodontida)as chaetognaths, At the time ofthis writing, skeletalapparatuses despiteconsiderable histologic similarities, but of speciesthat representmore than 100genera as representativesof a group that developed havebeen recognized from naturalassernblages from a common ancestor.It is my conclusion, or fused clusters or have been reconstructed which is further developedin Chapter8, that from recurrentgroups identified in largecollec- the Conodonta,Paraconodonta, and Chaetog- tions of discretespecimens. For the most part, nathaare similar but divergentgroups, all pos- the classification adopted in the Treatise pro- sibly of phylum rank, that developed in the videsa satisfactoryframework within which to generalradiation of major structuralplans that assessrelationships of the speciesso recon- characterized the Cambrian history of the structed or recognized.However, discoveries biosphere. since 1976,when the f,"eat,semanuscript was It would be an unjustifiedextrapolation from essentiallycomplete, dictate some rearrange- Phakelodusto assignall 15 generaincluded by arualJs Ebt -rxes Aq pazualc"J?q3 sercoos $pnlc ruroJruos 'po^\oxnJun lnq 'Peleuls lds uoDlueld luopouoc .'t\ -ur rapro eEJ?l sql sro\tne asuoatJ eex sesnleJ"dd?^lpJetel elsJqlrr3tuqlnu : a 'Jo8ec Jo Jo :H sapulnc -€qleuEqod eql ,{llErtuessesr eJeq ro^U"rcgrns -run llnq l3q1 sluopouoJJo erJuJS0z roJ -A €requeqtlg pe \olloJ arrreqss^lrrueJredns eql Jo epurpo{ftzo aql peqsllq"lsesr eprluoporepu?dolordeql sJep I puB eJueuv 'JJpJOSrql Ul apnlJul sJllrrrjBJ eql ur HJuaS -Jo e^g olur pepr^rp$ luopouoJ ss"l3oql 'pe) I s plt v u eauSoceJ 'suruq Jo suorsuelxe e{quuoJ 'usruo^ooJqlJo pu3Jql .{q nq uI Eluop t€ I r't 'rel -l?ld dola^op suoqrsod d eql ur sluorxolo plp l3urlxa,40ueJEddE s"'r lnq 'PeJe^ocslpleJ snql [ ,rellnt]^l f l{ l repro eql Jo ,irolsrq eql ur el?T :solcluap lseplo eql 'eE?u?uqure3 el?.l Jo sluopouoc / -c 'roddEft elqeed qll,{ las puE lsnqoJ eq ^luool puet slueur sePnJJurss?lJ JqI uon?JJJssnonJtdsuoJul s "-I c '{l?lJ -elg 'suoursod eqlJo qloq Jo euo ur sluourele pu" pe63?rJo,4luo slsrsuoc flueulolsnc 'uo,f, d er"J/€lp uroJl^erq Jo urJoJrsuelxe qllt\ sesnl"l uo4?lncrluep^Ilsoru pu? 'sluerualaJo ses?qeql puo^ : leurqs rfd I xaPul uI '16 -?dd€ alerqureu4dos 01 -Ixes llnq sluopouoc -eq lE ,fue^puelxe 'podole^epJr 'sossoc )1w6t).- eprurpouolrd ?ec?qleuSoJrqJ -ord saBr^EcI"s"q deep^leJ?Jq1v'\ sluetxele (Pel?ul.s '9€r'sg6r 3q1 ur sroqln? ,,rllrr{ ,{q pepnlJur^IrurE#edns ?Joueaeql Jo)qloouls pesodruoc ,{uo IpuoJ Jo .- JO oIIIOSSapnlsur OSIEpue aslpatJ sesnlErsdd?^Heo,'a,(Iuo[?lele{s elPJqureurlllnur^lprcFnsJo 01 -lun 19€6r) '"p4uoporepu?d 'zL aql Jo ?ocslleloPuoc pu? ?ecsllepJeqqrH^ruouoxEt sell e^"q sercadstuopr^eJ pu" -l ser -rruqredns eql seurquoc Eprurporuoud eqJ sPrluoporuoud sJepJoaql se pogrluapr eleq -raqtunu ."plluoporuolJd Pltl PUE'- seuo8alecrueue8?Jdns ur papnlculeJe^\ qJrq^r f r!r/n I u?d aql Jo solru?J snoue^ ur eJeuet gt roJ ec?ld 'a"pqlapolegpu"'eeplllesuv'o?plluopoE(d ,ffiolol I aql Jo ? punoJ e^eq I 'Jerlle3ol[Y '?prurp seqrurq eql ol pu" EeJ?ulqsruJncpu? eec?l uosu?Jg "{[e^!cedseJ t € E -olJezo pue ?P|luopouoJoJd:ql ol pauSrsse -uopouocordsarlnuqJodns aql 01uoq"cgrssE[3 l 'sl puawoN erp qcrq^\ '(o?pDuopoqledsorsld pu€ a"p4uop asuDatJ elqlur pauSrssesluopouos e^luurud Frg-re1se^lfs ) -f -J 'uosuPrg -o8^d) sdnoJAJeqto o^U epnlrxe I pu? '?ecel Jo sJeueEgl epnl3ur 'nuopr^?J ss?13eql Jo .r Lz'(6zd0s -uoporElsrc aql ol sroqln" ,srrDatJ Aq peuers '?plllepolegpuE ?prluopouosoJd srepJo eqJ oqo ur sluep -s? (e?pquopolsro eq1) dnoJ8 lu?Uodurr ue '[z] atq p (uErf,r^opJo lI uI epnltul osle 'le^e,{\oH uorl?cglsselcastl -elrc^efpeerp seu?u dnort-rapJoeJ? (eplulp p ruo{ sluopo I -oaJJ atll eersluoporuoud ,tlrurEJuedns eql -o{r?zo '€prluoporuoud)gcrq^r roJ l{ s'ruo4sSreg Jo Jo z 01 lUelUOJpu? edOCSur Jelrurs sr dnolS luopo 'slapro , otul pephlp JeqUnJeJ? qJlq/t\ ^luo'Iluop saJuararau -uoc Jofeur srql 'pe^recuoc snql sV suonrs -r,teCpuu [1] rluopouo3 'sass?lcZ olur pepll -od d eqtJo rDoq Jo euo ur sSoleuepeuuoJlEld -rp srstuopouoJ eql 'Je^e.{oq'areH epuoqdol neql Jo slueurels el?u4s?d epnlJur pue eleJq -uopouoJ JepJoarlt sz asrpary oql ur pednoJ8 I J-\EqSetunlo^ Joql?r lreFerz) -uaurldos Jo -rxas eJe leql sesnlaed aJe,$,{eql lnq 'qcols Jof€ur tueJoJrp J'EL -de lelele)s qtp\ stuopouoc^llecrs?q sepnlcur oJeqpesod o,r{lluesaJdar ol J?eddesluoruela q3ns uo peseq eq ol oJe IxmoJ -oJd uoD"cgrss"Is aqlJo ?pquoporuoFd aqJ sercadspu? EJauaCJrsserJl oql Jo pue fue^ Pprlu4snllrPu? 'u?ruo^eo 3q1 olur lle,{r ero lllun 4eJls ourJ?ruezuapEJ?qc puE s{301 EB pel?Jlsnl te pJ?!\dn 93u?J puE $[coJ u?nr^opJo Je^\o-I ueuqueJ Jeddn ur lsrg Jeedd? Z ratdeq) pcd^l Ds3tJads ur lsJU rEadd€ '€pquoporapu?dolold eql ur uI pequosapeJnlJn4s e{IllllopOuo)na arll rllrtvl r osle PJpnlcur {Jo1s l?Jlsecu?u3 ruo{ Pedole^ep,(lorns qcrq^\ slueruelo uuoJruoJ pezD?qdsoqd,tDnols 3qr srsdou^s J0 'sepquopoJepu?d sernssg ro snaoJJnJIEurp 'ss€IJ pe? puEuoDnq -nlr8uol snoncrdsuoc pezuapErcqc 'sluaru elsJ?dese s? pepJe8ejlseq eq ,tTqeqordIILI lP SJapJO IUOpO -eJJ JI?JISPJpu? rr.rJOJlUOJ^q pJts^eJxe stuopouoiend eqf '(1861)Dls^{eruezs Jo esoql duoJ I"drcuud JO SosnleJpdde l?lelels el?Jqureurnburnb^ldJJp s? qons 'sorpnls arntnJ q8norqt poqsllqplse r sr reld"qJ s ol -rq e^rlsuusrp llnq ePtuopojepued eql eq uorlceuuoJ plnoqs {ooq sql uI r pornqrJlsrP?Jo " ur PepnlJur ?Jaue8luopouoJ 8 aqlJo sgrcads ^teuugepuolssnJsrP uro{ ureqlPJllrr!o J^eq I 'sluJtlJIJ 3€rel aql sr srql '4uopouoJ aqlJo srop luopouoJnJqlr,4\ surJoJ puE sluopouoJeJ?d eql aql FIuo Faru?e -Jo rJqlo IJEJo srolsJJus Jr.llsJPnlJur xlqeqord uJJ^ltequollJeuuoJ ollugJp ou IJAse st JJaql flD ur 413[ Illun sluopouoS 3ql Jo dnorS rofErx srql sJarllo osnBceg'sllelep crSololsrg ur sar6olouoqleJnl esJe^rp E. IIE Jo ,ral Jo [? orrJeJ sdocs ur pacnper Pue saqr -retuo3 pu? Joururpue uuoJ FuJelxeur " PIII,{ 'seprurpo{ -(ueJlJednsJeqlo ot^q sJoqlne a,r/tra{ .{q peutrss" fluellrurs^lu"d peorq e;o srseqaq1 uo .(Jeretlleluop f"uB ParrJoJl?ld eJeueS Jo requrnu E Jo reJsu?Jl r(q potueur -ouoJ erll ur srrrJoJo^rlrurud aseql opnl3ul d ateFBuE pu? -3nE 'uorlpJgrsspl, asuoatJ eql Jo Eoa?luopor?l 01 pegusnfun,{11enbe sr 1r lnq 'eq1eu8oleeq3 rxlureurldes ro -src oql eJ?iseqt 'ued lsour oql roc 'slueualo aql ol EprluopouoJ?ledeql ur sJoqln?a'sllra4

YJ,NOCONOJ :IHJ TAXONOMY 43 h:e are the Dis- or septimembrate apparatusesu,ith carminate F6hraeus,L. E. (1983).Phylum Conodonta Pan- bi-ncation, aug- and angulate pectiniform elements (or their der, 1856 and nomenclatural priority. ,Sl,sl. genera zool. 32(4), 455-459. rber of platformed analogues)in P positions. The ozar- lcher superfam- Hadding, A. (1913).Undre dicellograptusskiffern kodinides, which appear to have been the most i Skanejdmte nagra ekvivalenta bild- aoval of a few liirmed diverse of all the conodonts, did not appear ningar.Lunds Univ. Arsskr.,Avd. 2 9(15), l-90. l'rte Conodonta until late in the Ordovician and persisted into Harley, J. (1861).On the Ludlowbone-bed and its E of all other or- only the earliest part ofthe Triassic. At present, crustaceanremains. Q. J. Geol.Soc. London 17, 542-552. this is the largest conodont order, with 55 gen- x-a included in Hass,W. H. (1962).Conodonts. Pp. W3-W69. In era distributed among 12 families. Treatiseon InvertebrqtePqleonlology (ed. R. C. hctive bi- to Chapter 5 is devoted to a description of the Moore). Pt. W. Geol. Soc. America and Univ. lparatuses of principal components of each of these con- Kansas. d raslrate ele- odont orders and to a discussion of the distn- Hinde, G. J. (1879). On conodonts from the Chazy and Cincinnati group ofthe Cambro-Si- fr-rous longitu- bution and geologic history of these groups. A hderodontides, lurian, and from the Hamilton and Genesee- synopsis of the classification followed here is shaledivisions ofthe Devonian in Canadaand I erceslral stock also included as Appendix A. Apparatuses of the United States. ./. Geol. Soc.London 35, ppear 0. , first in typical speciesof many conodont generaare il- 351-369. I range upward lustrated at appropriate places in Chapter 5, Huckriede, R. (1958).Die Conodontender med- iterranen Trias uod ihr stratigaphischer Wert. and illustrated discussionsof additional species kihcation pro- Paldont. 2.32, l4l-17 5. are to be found in the Catalogue of Conodonts Kohut, (1969). Determination, statistical lIirh skeletalap- J. J. (Zieglel 197 3, 1975, 197'1,1 98 1), of which four analysis,and interpretation of recurrent cono- r- or septimem- volumes have been issued to date, dont groups in Middle and Upper Ordovician hents or their strata of the Cincinnati Region (Ohio, Ken- hh of the P po- tucky, and Indiana). J. PaleonL 43(2),392-412. (1970). lffs major con- References Lindstrom, M. A supragenerictaxonomy ofthe conodonts.Lelhaiq !, 42'7-445. : and content to (1966). Pander, C. H. (1856). Monographie der fossilen @ of the Trea- Bergstrom,S. M., and Sweet,W. C. Con- odonts from the I-exington Limestone (Middle Fischedes silurischenSystems der russisch-bal- *o include in it Ordovician) of Kentucky and its lateral equiv- tischenGouvernemetts. Akad, Wiss. St.Peters- iodontidae) as- alents in Ohio and Indiana. Bull. Am. Paleont. burg,9I pp. tte Distacodon- s0(229),21 t-441. Rhodes,F.H.T. (1951).A classificationof Penn- E gmups (Pygo- Branson, C. C. (1957). Comment on the Moore/ sylvanian conodont assemblages.J. Paleont. "Parataxa PlaL" Bull. Zoo l. 26,886-90r. *lae ). which are Sylvester-Bradley Nomencl. 15, 169. Schmidt. H. (1934). Conodonten-Funde in ur- 3a ard Ozarko- Branson, E. B. (1938). Stratigaphy and paleon- sprunglichemZusammenhang. Pqliiont. Z. 16, z I have found a tology ofthe Lower Mississippianof Missouri, 76-85. r &m ies of the Panl. Univ. Missouri Studiesl3(3), l-208. - (1950).Nachtrage zur Deutung der Cono- -, and Mehl, M. G. (1933).Conodont stud- donteL Decheniana104, I l-19. ie^snumber l. Univ. Missouri Studies8(l), 5- Scott, H. W. (1934).The zoologicalrelationships r rhe superfami- of the conodonts.J. Paleont.8, 448-455. frlellacea of the -, (1936). Geological afrnities and taxon- Smith, J. (1907).On the occurrenceofconodonts iludes some of omy ofconodonts, Geol, Soc.Am. Proc.Abstr. in the Arenig-Llandeilo formations of the i aurhors in the 1935, 436. SouthernUplands ofScotland. Truns. Glasgow r. Prioniodinide -, (1944).Conodonts, pp. 235-246, pls. 93, Nqt. Hist. Soc.,n. s.7(3),235-252. North America (ed..H. Stoll, N. R., Chm., Dollfus, R. Ph., Forest, J., i.mbrate appa- 94. ln Index Fossilsof W. Shimer and R. R. Shrock). Wiley, New Riley, N. D., Sabrosky,C. W., Wright, C. W., railbrm digyrate York. and Melville, R. V., Secretary(1964). Intema- :P positions. Ele- Clark, D. L., Sweet, w. C., Bergstriim, S. M., tional codeof zoologicalnomenclature adopted F tr'ith peglike Klapper, G., Austin, R. L., Rhodes, F. H. T., by the XV International Congressof Zoology. pp. tsi of the order Miiller, K. J., Ziegler, W., Lindstraim, M., Int. Trust Zool. Nomencl.,Londoq 176 (1981). Cono- Sweet, W. C. (1970). Uppermost Permian and x develop plat- Miller, J. F., and Harris, A. G. d,onta. h Treatise on Invertebrcte Pqleontology Lower Triassicconodonts ofthe Salt Rangeand l I recognize 34 (ed. R. A. Robison), Pt. w, Suppl. 2. Geol. Soc. Trans-Indus ranges,west Pakistan, pp. 207- ie rn r}tis order. America and Univ. Kansas,202 pp. 275.h Stratigraphicboundary problems, Perm- drme followed Eichenberg, W. (1930). Conodonten aus dem ian and Triassicof lVestPakistan (ed. B. Kum- r! Pol;gnatha- Culm des Harzes.Pa ldonl. Z.12, l'77-182. mel and C. Teichert). Univ. Kansas,Dept. Ge- Mccowan, J. A,. (1963). Zoo- ology, Spec.Publ. 4. : large order in- Fager, E. W., and plankton speciesgroups in the North Pacific. Ulrich, E. O., and Bassler,R. S. (1926).A classi- eued by sexi- Science 140(35 66), 453- 460. fication ofthe toothlike fossils,conodonts, with I iDsour 'sluour !rcJ Sluopouoc r (086I) ra IW Jl".l uI p4eul I pu? afuq sql ?ntJur 'uml^qd I al;)q lnq sassld F e se (8t6I) Dpouol eql 4lD.DloJO^Qpue Dtopouuud se) ql epe(u sluop !I' Ur $Jnlcruls Forl] 'sesnlaed Farurun peuIJoJ rxrale poceJins {smtuusrP ar? l sruopouocerlJ r puop!^BJ z's

.eplu '?PuuoPoruoud lEedoloJd olul r{ pue epnuopo 'eluopouoS arll Jo suorsr^rpluecuruSrs ssElcelsproqJ eql Jo uo$I^rp e s? pop.leSeJse,$ leql se pezruSoceJJe8uol ou eJe posodord oJe^{^llm(uouoxEl Ioql qcrq^\ ([uopouoJ ssElcqns),tuo8elec dnorS-ss€lc JoJ 8f6l) :pro ol.urpepl^ " L roJ seuoSolec eql lnq s,ouelrEJael,,\l uosuErg Iq parnporlur sP^{rluopouoJ or!?u eqJ J pus ..'seluopouoJ,, FoJ rtuopl Jo sur,{uou,{srorunf ore sotueu osoql 'roqF8o1 uo{"I rEsls Jruouox?l 'tt6l q lqehl pu€ uosusrg Iq spunojS lErnlcruN uo saloN F :ra^e,{oq' eH posodoJdseuuoJrluopouoJ pue seuuoJtuopornoN srep tqr uI epuoqd -Joqns oql 01 'osJnocJo 'serldde eluEs oqJ sluopouoc ; eql uorlDcgrsselcposr^eJ ,{tII ul pasn sorueu 'dd 'ue8 rarlJelloc Jo Jeurpro Snn Pessnt aqlJo Jo u. uou,{s rorues e peJeprsuocoq louuec -11U5'8unvuotlq Jnqs8o4aI aq Js, Uoqaz 1 a 4 q?S oql Proconodontus)ancestors, which --=6ri \l.bl in 1944. taxonomicstatus and treatedas 2 classes,Cav- might suggestthat the Conodontaare polyphy- E-r s\nonyms of idonti and Conodonti. These are further di- t :alegories for letic. The possibility remains,of course,that vided into 7 orders:the Cavidontiinto Procon- !F :rcognized as the Cavidonti and Conodontiwere derived in- odontida and Belodellida;and the Conodonti a* Conodonta. dependentlyfrom ancestorsin the group as- into Protopanderodontida,Panderodontida, signed to the order Paraconodontida by Zrea- Prioniodontidd,Prioniodinida, and Ozarkodi- /ise authors. At present,however, there are nida. reasonablestructural grounds for beingskepti- cal aboutaffinities between paraconodonts and 5.2 Cavidontiand Conodonti conodontsand, on thosegrounds, I haveomit- ted the Paraconodontidafrom this discussion The conodontsI assignto the classCavidonti (and from the Conodonta).Answers to all of are distinguished by thin-walled, smooth- thesebasic questions are surely lurking in asyet surfaced elements,primarily coniform, that undiscoveredor undescribedcollections from formed unimembrateto quinquimembrateap- Cambrian rocks. paratuses,most of which apparently lacked structuresin either of the P positions.Cavi- donts made their debut in the Late Cambrian (Cavidonti) (as Proconodontus)and persisted(as Belodella 5.3 The Proconodontida and Its Fanilies(Fig. 5.1) and.Dvorakia) into the Devonian. The Conodonti, establishedby Branson Speciesof Procozodontus(Fig. 5.2), founding (1938) as a subclassof the vertebrateclass stock of the Proconodontidaeand the oldest Piscesbut here regardedas a classof another conodonts known, built an apparently uni- phylum, includesthe bulk of the Conodonta. membrate skeletal apparatus composed of This large and important stock apparently orig- relatively large, de€ply excavated,smooth-sur- inated in Late Cambrian forms assignedby faced, hyaline coniform elementsthat harre Mifler (1980) ro Teridontus.Typically, these subsymmetricallyoval transversesections and conodonts formed longitudinally striated ele- keelson the anteriorand/or posteriormargins. ments,mostly with relatively short basesand The marginal keelsof some elementsare mi- ll€rru ]I 'os JI prdole^op lvcttNoooNolo 8d F lvorrNocolAcuo3 stse8ilns J t t"ql 'Z\4S- lvcrr Nooo t l]XAUI _ lVOtrNOoOCAd fplsnorquDJ \=--4./ rx)rge^ urJoJr .s.) ^o1 ^r.a ^r.t """t ^""t- ,.'"t' ,"t tJ ^."t .'>""'a..* o opouocoJ d c) I oo z

tsdvc - (n c - t z 9, exAlJ m

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-rrr?J ? sr Jeglo er4lt:snpolsrcotquoJ Jo lueuod o/$ aql '(rel[Il I) snJuqwoJ snpo$tootquD) -ruoc I?lele)s el?lnJruatuou or Jo enSolouoq 'uerJr^opJO pol"Fcrluep eql sr euo '.uoqs ul elSue alnc? ,tlJ?g eql otur e8?eurl aql ponuquoc pu? ue qlIA dsnJ oqt surofreqlo eqlJo lsgt s?ereq^\ u?uqueJ lselq eql ur per?edd" '(6961 'rellln) 'aNnJ qtoours p ul dsnt oql surof Juo Jo sseJ sntuopouoJotd ur popnlcur Allzureuo 'snluopo -ord rouelsod erB l?ql ur [lu?urud JeJrp sluoru -uo)og 's{ao.r aeugr.u?c laddl] ur i(luo pezuSo -ele elerq"lop eseql selJpuap I?Je^3s reeq luq1 -cej st 'e?pDuopouoroJd eql Jo Jequreu e^r1r sess$oJd Uoqs olur lno u^\DJpeJ? Sedf,l luaur -tuud oqt 'snuopouo)otd dsnc lueq,(l[Elet?l E -ela pale^?cxa i(IdeepqloqJo suralEu Jouelsod pu? oprs suo uo euuec e glUAleqlo eql 'uorlJes (sasnl?redd" ;i;i) eql lnq eleJquleurrq ,4q peqsm8 ssoJc lBJuleurul{s ? qlyA ed,q euo 'sluoru !i'" , -uq.srp osls er€ (Z S 3H) senads snpol/tpto) -ele uJoJruoc elq-snluopouuo.td prqle Jo sesnl r 't..L . 'IJOIS I"JlSetU? -€r?dd? elerquraulq tllnq teql sprtuopouoc perrjnseJd eql 'snfl,ropouorog Jo luzurele culalu -ord roJ (086T) rellrw ,(q peqsrtq4se seA,\qorq,{l -ul(s? eql 01 J?lltuls sr reqlo eqt pue '(Z'S 8lC) snuopouoJog paui\eds snluopo el?lntlua8 puu pel€A?cxe^lesoJc .{Ideap sr ad^l lueru -uo)otd 'ln.qeP u?uqur?c el€.I slr Jsue uoos -ele euo qcnl^\ uI snleJpdd? el?Jqrrjeurq e llmq 'sluopr^ec aql Suoru? ezrutoceJ I l"ql JepJo '3rl) (Z'S snuqlun snpotstoolquoJ eepuuop puoJos eq1 'epqlepoleg eql Jo JotruaSold oslE -ol,tproJ eqt s? I'S 8rJ ur pelquasse se{. sntuopouoJold leqt (lseol 1? 'slu ot) sotE3 ^Irruq eft 'repusd snporlpn) Jo sarsads pra^as oql -rpul teqt seJnl€eJeql Jo auo sr uJetl?d Jo uos pu€ 'Surpue-J snqpuSopd1J Jo serceds uAroDI srql pue '4elJes ,{Ir?InAe!r roqleJ pue .{[elnu

VJNOCIONOJ AHI THE MAJORCONODONT GROUPS Lc tanding, and ba.-r Pander, are : Enrll Cordylo- dr:crts (Fig. 5.2) ih qhich oneele- d a.ndgeniculate k to the asym- Ir Lhepresumed t! :re alsodistin- Euses- but the lt ercavated ele- b s5on processes E dolabrateele- t posteriorpro- r srooth curYe, tle cuspwith an le denticulated h slieletalcom- Polonodus E orher is a ram-

*E:dae. Fryxello- &&iodonridae.

F ryxellodontus Cambrooistodus lapetognathus

Proconodontus Eoconodontus

Fig. 5,2. Elementstypical of speciesassigned to various generuof the Proconodontida.

iform version of the geniculatecomponent of en with Proconodonlusin a singlefamily, al- Cambrooistodusapparatuses. Miller (1980) thoughthis would surelycomplicate diagnosis suggeststhat Cambrooistodusand Cordylodus of the Proconodontidae! :tE !: developedindependently from Eoconodontus. The two known speciesof Iapetognathus Ifso, it might be betterto includeall threegen- (Fig. 5.2) are representedin Early Ordovician f 'elpolols UJou -pEnb IepruIBJAd oql esneceg seloeds snpouol 'snpoJuaNpue e'9 Atl) snluop -rdrJo sesnl"Ddd? eql ur lueuele olErpeJq aql snpouolodJaJor os[? 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'sluaur Jo reqrJdnuesnruopo axfuI otpeu8rss? rpoglpolu F lerlual eqJ -ele urroJruoJ pet€A?cxa ,{JI?rc -uel seq (tZ6 T) IF?tueS 're^o,t\oq :4erls^ls^rl?t uerc Edd€ aql ur uorl -edsJo sesn1elEdd?A"Jqueurup?nb ^ldeop tlmq l?ql -r^opJo les"q rrro{ oJe srrrJoJ$ellJDg peqsrl Du 'Jug dolo^op sercodsu?I'r^opro elpprf{ S Jo t sepnlJ -q?lse uooq te,{ tou seq snluopo axtutr t )ou91sod 'Jou -ul '(€86I) uerls8reg ,{q Ielep^lJBe uI possnrsrp Jo etupr^Tu'IJg crqd?$lrl?J$ eqJ-'snleredde sn opol rsluauale esoql ueeq s?q qcrq \ '(e'9 'Ac) snpoS,td pxtul eW ur tols J I eqt 01peuErsse elaq sr 1r r sluelllele uJoJ ^nuocer 'suJurrJJds,(ueu os 'uon$od S ,(ueur lg ol rueeslou saopxade f,-uqt fue uo peseq sr JeJ snql pequcsep serceds pepunor,{lP?orq E qlr^l lueurolepedEqs-uellru g|als el?rqr!3ur^llEcrdfl eql Jo guou lnq 'snl?JEdd?el"Jqruaurq ? u?ql 'pesserdurooV 'ur8J?urJouelsod elelncrluep +JO Sql Ur eror.upedole^ep srpouolod serceds,{u? teql ,(lepnlcE o^pq,(Bur pue pesselduocf sr ^{eU Jo l?letel pflepoleg elueu 1e,{ s? ecuepr^e ou sr eJeql serceds snoue^ uoqrsodcS eqt ol u8rssEI luauIaloaqt qJrgx,ur aEl aql Jo Jepro Jo slueuelo uI seuo fu"lprsqns olur epr^ seuesuonrsuEl-fuleuur,{s e ncunsrp B rrrJoJ Polrg pue 'eep4 -rp ,(?ur soqol fueurud aarql oql qEnoqlp 'elplp sod,qtueurolo oqt Jo eajql 'eurle/(q,{llBcrs?q lFuoJ Jo sdno$ -?Jul,{IlecrsBq sr od^t pelueurpuJo eft 1"(o sluellIele urroJruoJpeJsFns-qloorus I '(V xrpueddv -r aro(II Jeqto eql 'snue8 eql Jo l?crd,{l^lJ?lnEel se8pu 'pal?^ecxe Jo sosnleJ?ddeplolels eleJq I pue) I S 'ErCuI esopou cl4uocuoc Jo uJeUEd eql pu? 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I b Lindstritm riramate and tertiopedateelements of the Py- coniform elements,but the entire apparatus gecimen, which godus apparutus form a partial symmetry- has not yet been reconstructed.Walliserodus forographs sug- transition series,they are reasonablyassigned species(Fig. 5.3) had quinquimembrateappa- rilbrm element to S positions.The sprawlingcharacter of the ratusescomposed of keeledand costateconi- y inegularly dis- other two elementsis like that associatedin form elements,one a symmetricatform with lr rbrm equally other conodont specieswith P-position ele- anteriorand posteriorkeels and interpretedas ibsrrarions of a ments,hence they are assignedto thoseposi- an occupantof the Sd position.Dvorakia (Fig. E Aom the Early tions.That alsosuggests, ofcourse, that the two 5.3) differs from LValliseroduspintarily in that na.rm Mitler's known elementsin the apparatusesof Polono- apparalusesof its two known speciesappar- das speciesmight atsohave beenoccupants of ently lackedelements in the Sd position.Belo- E least 3 spe- P positions,although obvious elaborationof della, name giver of the family (and the order) of two the apparatusin the evolutionofPygodas from (Fig. 5.3), includesspecies whose skeletal ap- tl.ared-pnsed coniform Polonodusmay merelyhaye made room for ad- paratusesare similar to thoseof Walliserodus ry and bear sur- ditional positions. but are distinguishedby S elementswith finely k of concentric denticulatedposterior maryins. kributed ridges Speciesof Ansella(Fig. 5.3),principal genus c develops 5.4 The Belodellidaand Its Families of the Ansellidae,built quinquimembrateskel- four (Fig.s.l) ' ad two poste- etal apparatuseswith a geniculateconiform Enmc nodose In Fig. 5.I (and in the classificationoutlined in elementin the M position and an S seriesof : other more ir- Appendix A), I include three closely related elongate,deeply excavated, surficially smooth ! bsically trira- groupsof conodonts(Ansellidae, Dapsilodon- rarniform elementswith adenticulateor irreg- ry lobes may di- tidae, and Belodellidae)in a newly established ularly serrateposterior margins.Elements in i elements of order of the Cavidonti for which I proposethe the Sa position have three keellikecostae and cridBnce as yet nameBelodellida. All the conodontsassernbled are triangular in cross section; Sb elements &r eloped more in this new order formed quadri- to quinqui- have sharpanterior and serrateposterior mar- ,lrn none of the membrate skeletal apparatusescomposed of gins and a planoconvextransverse section; Sc . bsed on very typically thin-walled, smooth-surfacedconi- elementsare like thosein the Sb positionin form elementswith \'ery deep basal cavities. the apparatusesof most known speciesbut f, rccrntly been Thoseelements commonly havedistinct ante- areofbiconvex crosssection and, in a majority tu 11983),in- rior, posterior,and lateral keelsor costaethat of species,have no posterior denticles or brictan species developfine, needlelikeserration or denticula- serTatlons. paruses of spe- tion in the apparatusesof severalspecies. The apparatusof Hamarod.us(Fig. 5.3) ap- d !-oniform ele- The central stock of the Belodellidais the parentlyhad a geniculateconiform M element rbe homologous Belodellidae.Treatise arolhors assigned,S/a1o- and a symmetry-transitionseries that included theelobed ele- dus, Belodella, Coelocerodontus,and Walliser- a quadriramateelement with a few anterior (Klapper position, r of 'r'hich are odus lo this family. I add Dvorakia and lateraldenticles in the Sd and lat- lmenr\ with in- and Barick, 1983),which was describedand erally adenticulatealate, tertiopedate, and do- inel) denticu- named after the Trcatisewas published.The labrateelements in the Sa,Sb, and Scpositions, rrgins. One of better-known belodellids formed quadri- to respectively. Typical of the Hamarodus appa- E described as quinquimembrate apparatuses of slender, ratus,however, are a pair of deeplyexcavated, Fmerricat; the deeply excavated,smooth-surfaced, basically laterally compressedelements with serrated r BeEstrdm (in coniform elements,ornamented by longitudi- postero-and antero-basalmargins. Evidently lL One of the nal keelsand costae.The latterbear minute ser- theseelements occupied P positions.Affinities lenrs in the ap- rations in severalspecies but are undenticu- of Hamarodusarc anythingbut clear.Elements cicall! trilobate latedin others. assignedto the S positionsare surely not ex- b rhe anterior The oldestbelodellids are includedin Slolo- actly like thosein comparablepositions in An- ble element of dus (Fi$.5.3),which Lindstr6m (1955)erected sella, which also lacks elements in the P posi- r sp{-a$'ling ele- for conodontswith deeplyexcavated coniform tions. But Ansells alsolacks featuresthat would diate and pos- elementswith threeor four asymmetricallydis- ally it very obviously with any other major I simpler than) posed longitudinal keels or coslae. Coelocero- group of conodonts,including the Periodonti- ;rrauses ofPo- dontus (Fig. 5.3), which may not be distinct dae(Prioniodontida), where it wasassigned in ryrarn idal quad- from Stolodus,includes symmetrically costate the Treatise(Clark et al., l98l). 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VJNOOONOS AHJ THE MAJORCONODONT GROUPS JI

tinctive pattem of chevron-shapedridges ad- whoseapparatuses include pastinateconiform jacent to the anterior margin. At present, BeJ- (or "acodontiform") elementsin an array of selodusis known only from Ordovician rocks. coniform typesthat is otherwisetypical of the Dapsilodusis also representedin the Ordovi- Prioniodontida. cian, but it is probablybest known and most With the exceptionsnoted, the Protopander- typically representedin Silurian strata. odontida is the major conodontgroup identi- fied in the Treatiseas the superfamilyDista- codontacea,which was based on the family 5.5 OrderProtopanderodontida,New Distacodontidaeof Bassler(1925). Unfortu- This division of the Conodontaincludes most nately, no one knows much about Distacodus of the conodontsthat built uni- to multimem- Pander,1856, whose types are presumably lost, brate skeletalapparatuses composed of longi- or about the Distacodontidae,based on it by tudinally striated, laterally unfunowed coni- Bassler(1925). Consequently,I suggestthat form elements. Expresslyexcluded are the Distacodusberegarded. as a nomen dubium ar.d. panderodontideconodonts, a goup that built that it not be usedas the basisfor any supra- d apparatusesof coniform and rastrate elements generictaxonomic units. The name Protopan- with deeplateral furrows; and the oistodontids, derodontida, although a mouthful, is taken

Fi9.5,4, The Protopanderodontidaand Panderodontida.The families Protopanderodontidae,Clavohamulidae, Acanthodontidae,and Drepanoistodontidaemake up the Protopanderodontida.The Panderodontidaconsists of the singlefamily Panderodontidae.

z 9

o G thca

&- Components Iosed by Sb, Sc, PROTOPiAN r elementmay be

\*s r oblique orna- ;ior margrn. \d 5.3) formed B z rirh nongenicu- lmenrs in appa- @ Fg 5.3) are ge- DREPANOISTODONTIDAE ns areknown CLAVOHAM I a relationship raed bv the dis- ,{qpel?J€dos snql 'u€ruo^ .Erg) ,reyg4 a{rlleol lueur sr eruaJnccolsJg sll -de et"rqureurq e tllnq (9.S 9961 +nJo-soJ IIE 'sluoulele -oo eql olur pJ",'.\dnsetueJ pue s{3oJu?rcr^op snpo$oJouon sercads plql, se pequJs ,(lg6l) Jo r lErJrerrjrur(s Pele^ -rO raddn ur sJ?eddesnpopauoopnasd -ap snqt puEelrq,{ lsourp e8nols peuodeJ ^lJedord & alErqr.uounFru ecuern33o u€r3r^oplo ereteql uortcesssorc I?cqdrlle ^lelelduroc,(pqErls 01 r?lnf, '(S alppq4l ^q .snueE JD Jsoql eTI 9 ro^\ol snopruoueu" roJ tdecxE -rrc Jo slueurelerrrJoJruoc pouqcel l?q^rauos eqlJo ,selrq rdr.il Jo salcods JrlsouS?rp,tercadse oJe eseql pue Jo l3eJeJo snl?Jeddeel€Jqrleutrun p peuloJ + !6rel 3l6urs B Uod -uep T?ird?e{rlepou eoJrll ot euo dole^aposle 'sepuuoporopuedolordlseplo eq1 sepnl3ur snpopauoopnasd .^JIeJr i pJpselxe se,!leseq Jo slueuele lnoF eql qclq/*\ '(9'S '8lC) 0g6I 're rW snflopual -8o1oqtuourrelurrs ,tslg E mpolapuDdolold esr^uoqlotnq eqt ueql ',tJrurEJoql Jo sJequreurpazl tsnsl -tua^ eql uI 0e1 JepuaTseJoru pu? JeJlerussr ed^l luauele Joqlo -prcedsto paJu? pe aroru ur se8puJo ,eelsoJ r.Elsod Pa8Pe-tueqs eql :,(U?crd?ue{crqt l?qt sllE^\s"q pu" lnots 'e"uu"c purpnlreuot pe{leut aq ,{?I'u ,{lr .socqlns 1nq P PIqI€ Jo pesoduoc pue uoqs srad,{l lueujele euo q100rxs -ureJeqlJo stequaur^q rsldrurs aql uI peluetuEu ,pel?^ qrrul ol -lq ? qr},\ qlr \ sluaureleuroJruoc prqp -JOUn eJe SIUoUOIO SeJsd .SeCqlnS palEuls ^le^q?ler JO ) IJors tulSu?r-3uol -ecxe {1dsepJo snlaedd? Ielelels el?JqujorrJ ,{leug qlr^{ sluauela uuoJruocel"lnJruotuou qdr ol IsJlse3u" uaaq -rq e seq tL6l 'lrdea(Jq snpopauoopnasd 'plqp (^le^rsnlcxesu?eur ou 1nq) .lJ^Jl ErlsaSilns It S ErC JuJueBeql le Jo sosnter?dd?I?lolols elelquralu4lnru^q ^ll?rrdfl ot -run {l :rzlss'Dq'l 'sluopo uorlHBdostrJeu socueta.Ulplq8rTs eql eJnslou peurroJsluopouo, eseql .eEpnuopodolosspu? 4 fol muoJollqDuoA we | '.snponuozotuaspuP- snruopual lgeeY\t 'e?p4uoporepuedoloJd,eEprluopoloeuo.aep alerperuJelu ,peugep IFUJJar a^eg (986I) -eq srness snpopauo -nuopuel selJlueJeql ur sJoqtn?asUoatJ iq fllusrrnc FI sluauelo uJoJ sV eelsocpurpnlrtuol esJEocJeqleJ pepnTcursluopouoc ere srql ol peu8$sv EoJ 'prqF Jo snl?r"d ',t\ol A\aJe rrrroJ eruos pu?,elnl? JnJ dsnc ^lrluz; rununx?ut lxzuelJHeqc sluopo Jo lurod oql l? ur8Jeru Jouelsod 'utq.tlspa!1 aDpruopoapuvaolota,tlt?.l|! 1 g g lJo {Jols E peu/Yr"ds aqt uo uorl?tuepq tr{8ls e J?eqf?ur sluetuole 'uorpes D illBe eql ur assqJ ssoJcl"cndrtle ,tpqtqs o1 :e1nc ^ie^ -JI, slueuole uuoJruocprqp ,lnols rturs reu? fluot{s Jo Jo pesod 't s 'EIdul uzql aPrseuo uo e1?1 -IuoceJe^i sesnl?Jedd? esoq^\ serceds luopouoc ,{llmupuIuru]t?Ip u^roqs erEepuuoporopu€dol ,puerg Frrlu,{s? st leqlo 3q1 sapnlcur(S'S 8lC) (I86I puEuofurqtA -ord eqtJo €leue8 eqtJo sdrqsuorlEleJ ,ruorlspurl lEdrouud tu" seqpu? ptulelx ,{q psugepe:s?) 5g6l snpopauo paunseJd pue uorlnqulsrp crqder64erls eq1 'ur8wru r Jo ad,{l euo 'slueu JouelsodoglJo spJrqlo1r\1 'eEp4uop oqt Jeqlou? ,uo .sesnl?J?ddE r Jo snleDdd? 0131q I?tsrp 3o Jo eprsouo uo Jo elsoc -oJepuedoloJd eql lueuele ur.'oD[ Aluo esoq^\ 'fueqs B qlr^\ lnq sercedssn a ^ro!?u /I,/op!tal Jo -rrrJoJruorqlr^t sluopouorJo[lrurEJ o^rlJurlsrp ol u?rchopJo elp esow a{I sluarueTeurJoJruo3 prqle Jo snlEred lsolu puBtsetr?l eqlJo otq?ueql uro{ asEla snpouuozDruas ^lqeqoJd zfl poqslou 'eep[uopolopuedoloJdaqlJo eleuo8ereuo8ol peugNsepeugrsse ^ncuu serce(sercedsJo l"crd^l sasnlelEddEpuE sluauelg 's's '6Id Fg eqr Jo u?d lesEq tnpoao4 ltoJorutas ,(q peluJoJ snuo.otl|.,. A .t.p.{ttots .nPot.cu.dotot4 snlEndd" el"Jqrxeuj cds esoq^\'(S S 8lC) Wolluoxotwas 'uer3l^ e euDorrros epTsouo IJlelllur,(sE sI luaulelo stsod,(q po{u?U elsoc I E seq pue 'Pes$ld trJuleuul{s,ttlsJe}el Fsnleledde al?Jqureul torrrutrs Jo selceds 'oJaq^\esls [Jo tueuu8rssBl?llltu I leqt stseBilnssqt pu€ $solc slr 'snpoQauo !"rls 3lq?roplsuo3 ?

VINOCONO]:IHJ THE MAJORCONODONT GROUPS

a considerable stratigraphic interval from the components of multielement Tropodus Oneotodus,its closest morphologic relative, comptus,tbe type species,as form speciesof and this suggeststhat ancestryand possiblyfa- Paltodus a\d. Scolopodus,which suggeststhat milial assignmentof Pseudooneotodusmay be there is still uncertainty a'bout Tropodw in elsewhere. Lower Ordoviciancircles. Speciesof Semiacontiodus(Fig. 5.5)built bi- Semiacontiodus,represented in earliestOr- membrateapparatuses. One elementtype is bi- dovician rocks by a number of speciesprevi- laterally symmetrical,anteroposteriorly com- ously assignedto I contiodus,was probably also pressed,and has a posterior indentation or ancestralto the long-rangingEarly Ordovician costaflanked by posterolateralcostae; the other stock named Glyptoconusby Kennedy(1980). elementis asymmetricand hasa costaon only The only speciesof Glyptoconus(Fig. 5.5) that one side.Sometime early in the Middle Ordo- has been adequatelydescribed, G. quadrapli- :"ician, Semiacontiadzr gaverise to ,S/auferella callas(Branson and Mehl, 1933),has a multi- (Fig. 5.5), whose speciesformed a bi- or tri- membrateapparatus of hyaline coniform ele- membrateapparatus that differed from those ments that have only slightly expandedbases formed by Semiacontiodusspecies in that the and slightlyrecurved cusps that arequadrate in basal part of the finlike lateral costaeis dis- crosssection and bear prominent longitudinal n*-ldontidae. tinctly notched. Dzik (1983) suggeststhat grooveson the lateraland posteriorfaces. Semiacontioduswas also ancestralin the Mid- A particularlyimportant eventin the history hUtahconus(Fig. 5.5) formed a bimem- 6 tas redefinedby melrical and hasanlerior and posteriorcostael brate skeletalapparatus of albid elernents,one @- j.5) includes the other is asymmetricand more broadlycos- ofwhich is a primitive pastinate(or acodonti- tlh<€S were COm- tate on one sidethan the other. form) coniform element. Utahconus probably I elements of cir- Shortly after Sezlacontiodus made its debtJt wasancestral to RossodrJ,the oldestdescribed s These in the very early Ordovician, it apparently memberofthe Prioniodontida.Utahconus may dsntadon-ction. on the spawneda stock of protopanderodontidecon- alsohave been the ancestorof the Acanthodon- h oi maximum odonts characterizedby a multimembrateap- tidae,another of the protopanderodontidefam- fum a few low, paratusof albid, costate,and noncostateconi- ilies. ParutahconusLanding (in Fortey et al., &E. -\ currently form elements.Landing, Bames,and Stevens 1982) is similar, but its elementsmay bear rmediate be- (1986)have recently coined the genericname small nodeson the baseand along the lateral 'f]L.a; -t iodusi I am Variabiloconusfor the bestknown of thesecon- costa. r rerir separation odonls,V. basslui (Furnish,1938) (Fig. 5.5).In Fig. 5.4I suggestthat Variabiloconusmay have 5.5.2 Family ClavohamulidaeLindstom, 1970 , l9-J has a bi- beenancestral to Protopanderodus(Fig. 5.5),a r ot- deeply exca- long-rangingstock of Ordovician conodonts This family was establishedfor a small group t Erth relatively with a bi- to trimembrate skeletalapparatus of bizarreprotopanderodontide conodonts that I rl}e is short and composedof albid elementswith prominently formed unimembrate skeletalapparatuses of tho apically; the sharp-edgedposterior and posterolateralcos- albid elementsthat are surficially granulose, rd more slender tae.In the very latestphase in the historyofthe nodose,or spinose.Species of Hirsutodontus rilar morpholog- Protopanderodusstock, the upper margin ofthe (Fig. 5.6) built apparatusesof Teridontus-like lseudooneotodus basewas extended posteriorly and cameto sup- coniform elementsthat developedspines or Eilie apical den- port a singlelarge denticle. nodesat the base.The basalpart ofcomparable rdiagnostic ofthe Speciesof TropodusKennedy (1980) (Fig. elementsof Cldvohamulus (Fig. 5.6),however, lower Middle 5.5), like those of Protopanderodus, formed spread laterally to form a hemispherical rred- by Stouge multimembrate apparalusesof deeply exca- mound with a nodoseupper surface.Elements zrs ir Upper Or- vated symmetricaland asymmetricalconiform of Serratognathus(Fig. 5.6),on the otherhand, Erd inlo the De- elements,all of which bear three to firre prom- are anteroposteriorlycompressed, bilaterally lus separatedby inent keellikecostae. Repetski (1982) describes symmetricalstructures with a knifelike lower hecrtsuatcereqc eq plnoqs lnq elsJquaujul ro -rq sE ^lq?qord r uuoJruoc elqn poqucsap ,tluouIruoc sr t?ql snl?Jedd? IElalols E AelnJruaSuou e pEq (g'S 'fiI) snpo$rouodat( Jo sercods EueJl-futouruIfs 'rolsocue oql s? eEprluopoqluE3v {Erqtuaurup"nb eql Jo req(Irelu ^la{qraqlo eulos ro outpoqJuln .peuJnlut I) snpolslot0d sNeSSnsJeppJerlc srqt pu? 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VJNOqONOJ !IHI n9 I THE MAJOR CONODONT GROUPS 55 nilbrm elements of recessivebasal margin at the anterobasal he- One element corner.Nongeniculate elements that form the 4rmmetncal, and symmetry-transitionseries in the apparatusof k and posterior Paroistodus speciestend to develop bases E bur the cusp is whose upper margins are drawn out poste- D rie base,which riorly. Dzik (1983) and Stouge(1984) have Ii5 Lindstrtim es- bolh suggestedthat this processbecame den- 'ntdodus for ele- ticulatedin the youngestspecies of the genus, i i !-onvenientto P. horridus(Barnes and Poplawski,1973). The type -i..m.k!el. may have The Panderodontida nrus of a species 5.6 d henceis not Speciesassigned to this distinctive division of rd this famity. the Conodontaare distinguishedby tri- to sep- F.d here to the timembrate skeletalapparatuses composed of t one another in longitudinallystriated, taterally furrowed con- m:lodu species, iform or rastrateelements. The latter are basi- hta row of nodes cally coniform typesbut have a few denticles beas an anterior alongthe posteriormargin ofthe cusp.In only d r}rebilaterally a few apparatuses(e.g., that of Plegagnathus) ilalin a speciesis are denticulatedparts of any elementsdrawn notch Patotsrodus out into distinct processes. -srincdveTle family is In my opinion the major diagnosticfeature -. Fig. 5,8, Elementsand apparatusestypical of species ofthe Panderodontidais the distinctive longi- assignedto generaof the Drepanoistodontidae. tudinal fissureor furrow that is developedon one or both sidesof everyelement ofthe skel- *t Fdhraeus consideredquinqui- or evenseximembrate. An etal apparatus,and I have excludedfrom the essentiallyerect, nongeniculateelement with order all ofthe conodontswhose elements lack L<- Paroistodus, equally concavesides and sharp anterior and indication of this feature. This means, of Ee of an impor- posteriormargins occupies the Sa position.Sb course,that my conceptofthe Panderodontida nide conodonts and Sc positionsin the transitionseries are is considerablynarrower than that adoptedin ! Lsad the name filled by regularlyrecurved nongeniculate con- the Treatise. L-{s notedearlier iform elements, which are flatter on one side In the narrow senseadopted here, the Pan- Edrs is best re- than the other and commonlyhave basal mar- derodontidaincludes Panderodus, Parapander- i thus is not suit- gins that are diferent in conformation.M ele- odus,P s eudob eI o dina, Be I odina, C u lum bodina, xic categories. ments are geniculateconiform elements,com- Plegagnat hus, Parabelodina, and Neopandero- E apparently the monly with long cuspsand much shorterbases. dus. Pseudopanderodus(l-anding, 1979) is ex- trnridae, has a P positions were evidently occupiedby sub- cludedbecause the ostensiblylatest Cambrian rirh a complete symmetricalnongeniculate coniform elements coniform elementson which it wasbased have .sinctive genic- with an acutelyangular anterobasal corner and subsequentlybeen determinedto be represen- 'X position,and sidesthat are almost equally convex. Certain tatives of Panderodus that were somehow qmmencally bi speciesof Drepanoistodusattained an essen- mixed into collectionsfrom much older rocks. B in the P posi- tially cosmopolitandistribution in the Ordo- The oldest panderodontidespecies known 'tr basalmargin vician, but the genusbecame extinct at the end had apparatusescomposed of furrowed coni- b ilaftened, or ofthat period. form elements, and it appearslikely that they Eacter suggests Paroistodus(Fig. 5.8) specieshad a bi- to were ancestral to species of genera such as mmber of the quadrimembrateapparatus that included a Pseudobelodina,Belodina, Culumbodina, and dEstor. symmetry-transitionseries of laterally costate Plegagnathus,whose skeletal apparatuseswere frg- 5.8) had a nongeniculateconiform elementsand a genic- formed entirely of rastrate elements.Conse- ronly described ulateconiform elementin ihe M position that quently,at first blush,it would seemfeasible to rld probably be characterislicallydevelops a conspicuouszone assignpanderodontide conodonts with appa- JrmbaPe u€q1 .e8s , -$dd? sercadsosoqtJo snleJ?dde eql uerc snqpuSouDn!' ol peloJsueJl s?^\ saneds l€qJ ssunEJ Ers PUE -r^opJo alppr,,{ ,{Jpe Jo $lcoJ ur petuesoJdel (€16I ) Dts,r"ldod pue seur"g Aq s,?/.rpruutso D ur palEllsnlll erc snpoDpuDdDtDdJo sercadsl"uonlppv snponpuDdototd Jo sed^l eqt ap?u ere.{\ qcrqnd pelueseJdeJ $ [ (3961)1re13 pue uo1 'slueulalg urJoJruoJ'pe,rt\oJJnJ,{lsnoncldsuoc .rrEruo^aq eql -Surqlgpue 'oEnots'Dls,["ldod pu? seuJpg -uI lnq 'pet"uls Jo sed^l eerql I snpoDpuod sarnAUuI alqrsr^ flftalc sr .r\ollnJ eql Jo uorlrs^q 1s"01leJo posodruoc^lsnoncrdsuor snter?ddE u? qlua soroods -iluo(uruoc arc -od eql ur urfueur ps?q eql ur r{4ou e 'Je^e^roq Jeqloue [q (euoz eE^g) uercr^opJo ,{lleg eql tttlaq suoucull :luau.Ielesrql Jo seJn8gII? ur eJnJsqosr ep$ ul relel peulof se^\ snlou$ snpotapuDdDrDd !z{ se 'qSnoql leql l?qt elou ol tursnruesr 11]'"lsor roualsod 'ecq rouelsod eqt ur deep e o^eq uon a. snpuapuDd ^{o[nJ -pnu aql Jo ur8r"ui Uel eqt Suop ouo s?g,{lJealc -cesssoJc JelncJrJJo surJoJ pue'suorlzrJls l?urp sEdde eql leql 1r tnq 'suort?4snll peqsllqnd ur -n1€uo1 eug lEeq sod/g gloqJo secElns auo3 " ^\ormJ nqI uorlcluls e IJ?l ol sreedde 'sniutawut{,r, d Jo pJrd,{l el?lnJruo8uou Julaujlu,{se ue leqlo eql ,uon . uo suoqselloc .srxp sr qcq,{ luotueleJo od,qJaU?l eql touel -cosssoJc JElncJrcJo euoc elelnJruatuou pe^Jnc TrEqrss'I lllJg -sod-Jouelu?eql ol prulou euelde ur pauell"U I ruec?Jt'repuels '3uo1 E euo 'sluotuole [uJoJ ()_I P pu? 'pu?[ ,{lsnoncrdsuocsr l"ql luaugle rrrJoJruocJuleu -Iuoo prqp ,tqee,n ,{po Jo eurp^q Jo snl?Jed eP snpotapu0d -ur,b? u? pue :qsoc rouelsod eql Jo sprs euo -d? plele{s el?rqueurrq ? p"q (6'S 'trl.) snlouts ,tFrl r.nautu^s uo AlolnJ ? rllr/Alueuole rrJJoJruocIecu 'd '0g6l) eenots iq snponpuodDrDd ot parJeJ ossddaf urroJ ^luo ., -leuru^sqns 'Jepuels? :^\ounJ snonordsuocur -suprl ,(lluaJer lnq It6I ur uosrtlA puE so eJC pu? r epls ouo ue ,tq eprsJeqlre uo peJeptoqElsoc Jouolsod snpt.tts snpouodate sE pauruuolop sueu lDJu[u,{s ,{lPJo ^q pPoJqe qlll'a lueurelerxJoJruoc elBle 'pelEuls -rcedsuo (?96I) {leIJ pu? uofurqtE ,4qpespq osuoJeJ snlur I Alpurpnlrtuol ? papnlcur pue et?Jqureuul seDads ? 's?rrr.{3 snpodoloJs Jo seffitueserdor qSnoqllv E|]JJ ls?el le se^,\l?ql snle[ddE ue p?q (€/61 se pepre8er uoeq o^eq sluopouoc |3p ur paqucsep 'Dls/A?ldodpue seull"g) snn4awulko snpotap oseqJ (ouoz raJnlaq)^luouuloJ u?rcr^opro fll€E eql D uEunlrs -uodo.tDdtern e?ou(996I ) tu?8tuCpu€ {tzc ur fue^ peJeodd?e?pquoporepu"d eql ol rtDlsoJtun^lJeg snpo .AUe olq"reJer^lr"e eq ot urees1?q1 sluopoum lsaplo eqJ (lsru ur asm eqt s€ tr roJ eruoq pooA se le\l sel]leuJsnpoap " 016I 'ruoltspu17appttuopotapuDd tltwDl sasnlEJPdd€ pl -uDdDtodJo sorcedsqlr^{ uouluoc uI sluelxelo J 9 9 rEq ol sluo(Ilele auos senqs 111?q1 p-J 0rl1pu? luoporapusd r){ peururJolep B ,{lernssr lr lEql eur pecur^uooseq suo4cel 'se8l?lue dnoJEEurlzznd srql lropJo Jele'I elq?lr?^euI 1o3 sercedssrqlJo suoturceds ,{ueru Jo etpel^1ou{ Jno se paprlrpqns eq ol Dodxo I uo pelenlrs sI $ aglJo uoneuruexetnq'peuousenb aq oslE,(Br.u qcrqa 'epprluopoJopued eq1 'fIulEJ elSurs? ol I sql puE 'pe^\oq lueluuftss?tEqJ (996I) 1ue8Aq pue 4zq ,tq ?p[uopoJepupd repJo eql ur pazuEocel ,(nuel ruorJ :eed snpoDpuodDtDd g^rleluaseJdeJ .crlal. 4q-I Jo e sB pel?eJl -rno sercedsII? u8rss?I '^lluonbesuoJ qd foal ur lueurele (tg6l) ',{Duecerlsolu 'pue e8nols,tq szpo4 -f1od eq p1no,lrstuauole l?telels elprls"r qlr^\ e^Eq E\BJ les€q -uorotuas ot pautrss?er'(6261) ulo4stuog fq sluopouoc eprluoporepued loJ peteoJc,(Iruq ? l leql $uauele lew pIJe 'DplnJruap DutpopqufiJ Jo Jolse'ue n) pesseJdurot ,t1a1qeq1 sr 'slueurala ptele{s ele4ser qlrr'r serc '(9861) -EpualsJo snl?r lueSIrC puE )tIzC rlrou -ads E tou 'tuaoqsSDq snpoapuod ler41,eu ot P,tq.uf) snoqns ErlopodJo ueunls aq1tuo{ sr sluouralcstlporap -rrd Jo Jolsnls pasnJ e\I snporapuod pue snpoDpuod s1se3llnssql 'DplnJuuap d Jo stueruele et?rl dd? eW '(8t6I) .6.S.8rd -rrrd Jo sosnteleddEoqlJo leord,{tsluoruelg -ser egl 01 lEsrluepr eshlJoqto el? leql slueur r&'llt{1tAJO UEIU -ele uuoJruoc pe,,llolnJ Jo snlEl?dd? uE p"q iFea aql ur JelEl rlcrr4[\'ruaotls8Dq snpoapuDd qlr,tl u?rcr^op snpolapuod 0 -JO al"-l eql ur eeseqt peJ?qs'sluaurele xIoJ plluopoJep ^UerJq ,D|DI eleJls"J e^nourlsrp Jo snlel?dde tE qllt^ E\eJ ueql Jo.{rol -n)nuap DutpolaqDt d s3 qrns sarseds'sr lsqJ sluetrlelo uI dJo 'e8BeurlJqel,{qdouoru e dn eleur lou,(elu sesnl ol sureesslueu -eJ?ddp ,{luo-e1eJ1selqlr^\ sepeds l?ql e^etl cPJlouetsod eql -eq ol uos€al sr eJeql 'le^e,'.\oH 'peul?u U luoporepued,, ^lruEJ -un le,{ s? 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VJNOOONOC AHJ I THE MAJORCONODONT GROUPS

ently containedonly two typesof slendercon- The youngestmembers of the Panderodon- iform elements, both of which exhibit a tidae are late Early and Middle Devonianspe- "panderodontfurrow" (or a pair of them) on cies ol Neopanderodus,which apparently had the posteriorface. The basalcavity oftheseele- apparatuseslike thoseof better-knownspecies ments seemsto be somewhatdeeper than that of Panderodusbut composedof furro\ped con- in elementsof P. asymmelricusblot m\ch shal- iform elementswhose sides are marked by lon- lowerthan cavitiesin elementsofyounger pan- gitudinal striaethat are more prominent than derodontidconodonts. thoseof Panderoduselements. Panderodus(Fig. 5.9) made its debut a bit The oldestrastrate elements known arefrom later in the early Middle Ordovician (Llanvir- early Middle Ordovician rocks of about the nian or Whiterockian).According to Ldfgren sameage as the onesfrom which the earliest arppanttusesof Para- (1978),the apparatusofthe earliestspecies, P Panderoduselements haye been collected. !lsed clusterofPar- ofPodolia. From sulcatus(Fahtaeus), had a birnembrateappa- Opinions vary as to the genusrepresented by -- ratusofslender (or "graciliform") and laterally theseelements. but I regardthem as specimens compressed(or "compressiform") coniform of Belodina.Later, better-known species of ,Be- elementsthat are longitudinally striated and Iodina (Fig. 5.10)formed trimembrateappara- ,4, ro Semiacon- havebasal cavities about one third ofthe total tusescharacterized by three differenttypes of d- most recently, elementin length.Elements of both typesap- rastrateelements, which are separatedprimar- f Parapanderodus pear from Liifgren'sillustrations to be slightly ily by differencesin their radii ofcurvatureand l Tbat assignment bowed,and the distinctivepanderodont furrow the number of denticleson the posteriormar- E mination of the is situatedon the outer,or convex,side. gin. One elementlacks posterior denticles and b in availablecol- Later Ordovician species of Panderoduswere is formally coniform. tar it is surely a determinedfrom large collectionsof discrete In 1979| describeda sequenceof speciesof lu ir sharessome elementsto have had quinquimembrateskele- Belodina and noted that in younger and lrfies of Parapan- tal apparatuses(Sweet, 1979), and this is also youngerOrdovician stratadenticulate rastrate I a home for it as the casein fused clusters representingPander- elementsbecome more numerous and coni- odusunicostatus (Branson and Mehl) from the form ones proportionatelyless so. However, EE rhat Para.pan- Early Silurian of Podolia,which were recently one Late Ordovician species, B. calcipromi- rs and Poplawski, describedin detailby Dzik and Drygant(1986). nens, is known only from largeconiform ras- q?s Fr at least Although certainof the elementsin the appa- trate elementsof the sort onceincluded in the r longirudinally ratus I reconstructedin 1979are nearly bilat- form genusEobelodina. Although specimens ar sith a broad erally symmetrical,they are furrowed on only assignabletoBelodiru are known from rocks of .drher side by an one side and were describedonly as "simili- latest Ordovician age,none has yet been re- *r. subsymmet- form." Jeppsson(1983) reports that there are coveredfrom the Silurian. rr furrow on only truly symmetricalforms in his collectionsof Pszudobelodina(Fig.5.10) has a quadrimem- ltr! and an asym- Panderoduselements from the Silurian of Got- brate skeletalapparatus composed of deeply I s conspicuously land, and a few have also beendiscovered by excavated, laterally furrowed, posteriorly r tb€ anterior-pos- Britt Leatham, one of my students,in the large "heeled," anterolaterallycostate rastrate ele- ldenent, which is collectionson which I basedmy 1979recon- ments.Three ofthese element types are bowed Itpears to lack a struction. Thus it is appropriateto conclude to the unfurrowedside and form a symmetry- Eradons, but it that the apparatusof fully evolved speciesof transition series;the fourth, which may have Ergitr of the mid- Panderodus was probably seximembrate al- occupiedeither the M or oneofthe P positions, 3 ro note that that though,as Dzik and Dryeant (1986)note, dis- is straight or is bowed slightly toward the fur- r of this element; tinctionsbetween elements forming the S series rowed side. The oldest Pseudobelodinaknown imargin in the po- arecommonly difficult to make. to me is an as yet undescribedspecies from 7 rrsible in figures Panderodusranged through the Silurian into Middle Ordovician (Blackriveran) strata in Ege- and Ething- the Devonian,but information on the species North America.Although elementsof this un- representedis sketchy.Indeed, specimens are namedspecies are all denticulalerastrate forms tognderodus arc illustratedin only a few reportson Devonian and thus morphologicallysimilar to compara- t Middle Ordovi faunasand Silurian forms have receivedless ble elements in the apparatusof Belodina spe- cse specresappar- than adequatetaxonomic treatment. cies,there is no coniforrnrastrate (or "eobelo- pu? -rp lueurdola^op .rraqlJo euIc? eql peqceoJ 'pue Durpopqopnasd ro Dutpopg tufua_Euol o^?q 01 tllaos sesnleJ?dd? qlr lualuole-elells?J \ oJourJo seoedsJo asoql ur peledrcrlu? lou el? sluopojepu?d eql eluos pue .sluopouoc Jo snpoapuDd sasnleJ"dd?JreqI luopolapuzd eql 'dnor8 aqt peteprsuo3 TertseJueIEcrEol lsou eq lI" Jo sosnl?Jedde,tluo-etejlseJ et?roqele lsour qcrq^l lsnu 'oulpolag popnlsur sluoporepued eql l[nq outpolaqD]Dd pue snqpu8D&ald tuerodruetuoC .uercr^opJo .uuoJruoc al?-I eqt Jo (u?rue 'slueuele e13[n34uep3 -pA) ljed flffa oql uI lnqap str epeu] tr oJeq^\ lou 'aleJlseJpeTeoq elB 1?q1slUoUOduJOr qll^l '?cuerrJv quoN ur ueql u?rcr^opJo uelJeqls lnq mpofipuod lo lEql 01 r€lrutrs ,{lp?orq snl eql ur rorT$e lrq E pej?edde AIq?qoJdsnueS eql -?JEdd?elHqr.ueurrnburnb ? pauJoJ ,?ouo(uv 'sou?Joduoluoc slr lo snuet eql lnoqD uo4?rx IIUON uJelso^t uI $[JoJ uErJr^opJO Jeddn peqsrlqnd -JoJur IIlo{ snohqo llE 1?tou ere out uro{ ,{luo u^{o(Dl osp ,(01.9 .B:.i{) Dutpopq -poqwryn) sul€,uo .setels c4euo8oluo Jo lsel?I -zlrd'seuos uonrsuB4-fuleuruj,{s ? uJJoJl"ql eql Eunuessldol slueutala ur tuesq? r{lelalduoc seuo pelElnrnuop,{TeloJcsrp .el4soc eq pu? .unAoJtJa^o eJeselJrluep ssoql eeJql pue 'ePIs pe/yrorJnJun oqt 01 pe^\oq^lT?Jolel euo ^eur ^eql Jo lsour 'sluetuole e8sls-rll,roJt Jelq ur :loeq eql 'eprs po^\oJJnJ eql pJEltrol pe^\oq euo .slueuJ Surpnlcur 'urEJ?urJouelsod aql Jo lsoul AuoI" -ole eleJlsprlcuq.srp ,{flec€oloqdJour a^gJo snl salJrtuop e^eq .e3ueurv gll.\oJ8 Jo seE?ts ,(Feo lueseJ -"Jedd" plele{s e s€q qUoN urelsa,n -qer slueulela leql aprs pe^{o nJun erll pJ?^{ ur 4el1s u?rsr opro JeddIl ruo{ rE snql pa^{oq qloq.sed ,(0I.S -ol t o,$lJo stuoulele aleJls?J u^\oDl sr gclq,r\ Etg) snqpu7o&al4^luo elasortlnrll ro .paprs-qloous 'u"rcr^opJo elpprtr l eql ur lerlJee qJnu 'poleeqJo snlerpdd?^lFurpnlrtuol Telolelsot"lquoulq z pEq I.'ols snpotapuDd eql ulo{ peleul8uo o^eq '11 'E]g,) lordralur I s? '(0I S DurpoqrurynJ feru qcrq,rr 'oulpopg uro{ pue snpoap 'sasnleJ?dd? lou plelels eleJqulelulxesJo -rnbunb -u0d wo$ ,([poJrp pedole^ep Durpopqopnasd e^?q sercedsosotqt^,snpoapuDd ,,{JluenbesuoJ.slJor I[? uro+ r(puep leql lr {uql I eruEs -uedapu pue pedole^ep Dutpopqond eql ur^le{rT peluoseJdeJ eff qcrq/h ,ossatdu,toJ .B pue snqpuSoSald^lperp nql lcedsns ecueH.twao.u pue I stsuatoluour outpopg Jo esorllpue sersods ' -sdnq mponpuDd snoeuelodueluoo Jo t?gl aurpolaqopnasd srrll Jo slueruele ueo^ueq uJoJ ol peleleJ sr snlel?dde uJ uorl"patJolur sr eleql qJrq,{\ ur suorpelloJ DulpopqD.tod^lleJrEologdlour arll..tno pelurod^losolo ,luourele e^eg I s? uaos lou e ?q I pue (,,r.uJoJrurp ^p€eJI?

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Jo s:_,lneluesordel r^opro'II'S'3!d

I riFJeurud eJa^\ r0r,$ 'spnuop lr-tt'ple^\elod lq sPun"J u"ro {dJJ uaoq e^eq Srp uElrlodour EI mpoDpuod Dlleqs ur ,(lrsje^

VJNOCONOJ AHJ 89 THE MAJORCONODONT GROUPS

versityin shallow,tropical, or subtropicalseas. 5.7 The PdoniodontidaDzik, 1976 Panderodusitself has a somewhatmore cos- mopolitan distribution,but it seemslargely to This major division of the Conodonta (Fig. have been replaced in higherlatitude Ordovi- 5.1l) includesconodonts in which one or both cian faunas by Drepanoistodus and, farther ofthe P positionsin the fundamentallysexi- or poleward, 14alliserodus. Specialized pandero- septimembratecephalic apparatus are occupied dontids, with rastrate-elementapparatuses, by pastinateconiform or pectiniformelements were orimarilv low-latitude forms. or their platformedequivalents. In a few spe-

Fig.5.ll. Ordovician and earliestSilurian families and generaofthe Prioniodontida.Later Silurianand Devonian reDresentativesof the order are shown in Fis. 5.17.

s a e t e a I i s I

Parubelodina l to I fl\ bergs- I il\ and ? POL e I and i-ndepen- i ies all have apparatuses. 3 I I interpret it, I a of heeled, \ I ! multicostate I PERIODONTIDAE AA to$ bowed to- J that rep- a tave il denticles including pI mostof ttrey may be l the of Culumbod- ishedinfor- lit €arlierin the noi America, . early part (Ed- Contemporary which must group. panderodonts seem to have and di il\ artouDnl' '(snll tta$euoatuanf luauelo uJoJ ) tnNtaou t9 etl) snqtDu P m}?r?dd? Ie1 lsmSu4srp ueoq q -iErusnpossov Fd-. puE slueu 4 raqlo eql uo) Dl o.Yrlsll oCueq pcdolr^ep rPossou 'pelues^lInJ !.oq lsnf eur ol 6 snqpuSouDnl' snpolslo'tL6l tr6I 'lolue^\ ssa\f, snponqd I '9581'ropued I qsledau snpos itsnlEJeddeqcns i 3ql uI lualllele rduou Peluau] 2 ol lualuels qs )e Jo uoll qtnuopolluoJ?,,)^8{.r,{q 4grp , leleldluoc EU€lI-fulerurui(s rrpolsro,,Jo) elel DPorE,,ro) eleull E:le uuoJruocJo 1tl6 I ) rlSEtueSu'Io4 stuavrele sn|tou&ouon[ s?ur^\sJC lo rEprluopolsro Jql Jo BJeuoBsnoue^ ol peuStss?sercsds Jo leard,{lsesnleredde pue slueurrl:I .ZI.S €!d

|rI EI's':t!rl snt"reddEletele{s et?rqureumburnb ot -up?nb -erdeJ osl" eJe ser3ads ese\L .mporcqdu1 Jo ? qtl{i sluopouoc epnlcur I srql uI ,,snpo)v,, ol sloqlo {q peuSrss?ueoq e^Brl feql ^[[ueJ lnq '(ZI'9 '4J) npoduJ ur eJoqpelqrxoss? oJe 016I 'urQttsputTa0pltuopojsto tltwo! I l.9 sesnl?Jeddeplele{s Elrrurs qlr,t{ seneds re8uno,{ f,RqArtS erreqrs pu?^lesolo ,u€rl ,Erl?llsnv ',{ua3ol^qdluoJeJrp Dqlel 'EoJo)I'?cueurv quoN ur serlrle3ol snoJorrJ e pelsea8ns .r?el3 s?q (tg6l) sne?lqeCpue -nu 1e06? uercr^oplo {lJsE JO$[coJ ut pelueseJ lnq Suq u? sr spuuopourr u€ruo^eo pu? -der ,(Fouuroc ere qolq,!\ '(ZI'9 .tru.) snpossoY u?unlrs relel pup sprTlopousru?rrnlrs-prhl ot 01 (0861) uofulqla pu? Dlsledou ,(q pautrs flJeg pu? gql u?rcr^opJouae,{rleq dqsuouElal eql -se o^U aJ? snleJEdd? IElelo{s 'Je^e^roq'e"puuopouJl oql Jo uorssnJsrpful epnuoporuoud^Dueunc e qtl,a serceds lsaplo eqJ ur polou sV snuet peueuun u? lueseJdel 'slueurole el?unsed go uorlecgrpour crlaua8 -qoJd pue snqnuSslqalad uro{ ,tlluepuedepur^[qe -ol^qd Jo crleueEoluo qtnolql uesue e^€q ot pe uap eJe,tiopnlcuoc (?g6I ) uesaelopu" SJeq (pereJur ,(lqEuoseeJlo) u^{oqs eq u?J tnq elel ^rcqt,,snpou4,, -pues, Jo sercedsupruo^ec elsl -n8ue Jo eleurluJ€J ,{IputoJ aJ? l?ql slueluele ,,tlunl?tu ,perdnrco praaes Alqeqorder? ep[uoporuoud tsetuno^ uroJrurtcod ,tq t? ts?el le '$[cols .suon$ oqJ e^rl3urlsrpJo roqurnu e ol pllssc aJ? suoqrsod d sJeqlo [eJe,\es uJ -u? aq 01 r?edd?pu? sacuoJJnmouersr^opJo -od IAIJo S ur paruJoJuaeq e^?q ol ruaessluoru Je^\o'Ipelu0rrJnJop{le^\'p€eldsepr^\ peluos -els pozrl?reurur ou 'soprluoporuoud pezrlen ^q VINOCONOJ 3HJ, THE MAJORCONODONT CROUPS 6l

Eumented Lower 4pear to be an- aive stocks.The ' probably seYeral 'r*J'that Sand- bde were derived lalus and prob- Eus. As noted in rDdae, however, ncian and Early rd tater Silurian fu alything but bs suggesteda

alstrom, 1970 rodonts with a Protopttoniodut Oisaodus ieletal apparatus Fig. 5,13. Elements and apparatuses typical of species included in three genera ofthe Oistodontidae.

*rudae. Drawings of coniform elements,of v/hich one (P) is pas- onym of Rossodzs,as noted by Repetskiand tinate (or "acodontiform"), one (M) is genicu- Ethington. late (or "oistodontiforrn"),and the rest form a Tripodus (Fig. 5.12) and Diaphorodus are symmetry-transition(or S) series,which, when basedon different, but probably congeneric. completelydifferentiated, grades from an alate species;hence I regard them as synonyms. ("acontiodontiform") elementin the Sa posi- Therewill probablyalways be uncertaintyas to tion by way ofa digyrate(or "paltodontiform") how Acodus (or many of Pander's genera) Sb elementto a compressed,laterally unorna- shouldbe interpretedin a multielementsense, mented nongeniculate ("distacodontiform") so I recommendthat Acodusbe consignedto element in the Sc position. Conodontswith the list of nomina dubia and that we go on to such apparatuseshave been included in Ros- more important things. sodrs Repetskiand Ethington, 1983,Acodus Oistodus, Protoprioniodus, and Oelandodus, Pander,1856, Tripodus Bradshaw, 1969, Dia- all shown in Fig. 5.13, include specieswhose phorodus Kennedy, 1980, OelandodusYan skeletalapparatuses are composedentirely of Wamel, 1974, Protoprioniodus McTavish, geniculateconiform elements,which neverthe- 1973, OistodusPander, 1856, and probably lessexhibit an arrayof forms closelysimilar to JuanognathusSerpagli, 1974, but it is not clear that in the apparatusofspecies ofRossadzs and to me just how many generaare really repre- Tripodus. ln lhe Treatise Bergstrdm expressed sented.Rossod?rs (Fig. 5.12) may not have a the opinion that furtherwork might showthese fully developed symmetry-transition series, threegenera to be synonyms,and I can seeno henceits two known speciesseem primitive. very goodreason (aside from the geniculatena- (On the other hand.the "acodontiform" P ele- ture of their coniform skeletalelements) to ments and "paltodontiform" Sb elementsof refer them to a family separatefrom Rossodzs Rossodasmay be so similar that they havenot and.Tripodw. Consequently,in the schematic beendistinguished). Furthermore, if the skele- classificationin Appendix A, I group all these tal apparatus of the tlpical speciesof Juanog- generain the family Oistodontidae(which has nathus (Fig.5.12) includesa geniculateconi- priority over Juanognathidae),btt rcfer Oisto- form element (Serpagliwas not sure about dus, Protoprioniodus, and Oelandodus to a this), Juanoqnathusis probably a senior syn- subfamilv Oistodontinae: Rossodus and Tri- E4s uercl^op r' pu? pezruSo rruo aql e^oqe UI Suruu€eg l -q!tuD.lE l9

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V.JNOCONO] AHJ l'zpodas. It is also &znae represents lhent from either bcauseit is sepa- 'frovician from I gpical Histiod- Ei describedonly q,dthough he now iulate coniform

?B2ssleL1925 t just above the 'ls debutare con- *ehral apparatus r are occupied by Enate elements Amo.phognathus res: rhe M posi- ictrlate coniform irnally a bipen- it an elongate, r pnocess;and S Eition seriesthat &re. alate, and clear that t-EDs Prioniodus Pan- I fnpodus, fiorn , in a somewhat Fig. 5.15. Elementsand apparatusestypical ofspeciesassigned to generaofrhe Balognathidae. rarus in which ttr out into den- greaterdegree of morphologicditrerentiation in groups of elementsthat representa phyloge- fr rhereis alsoa the S series. netic seriesofconodont speciesreferred to Bal- Prioniodus(Frg. 5.14) developed phylogenet- toniodus(Ftg.5.l5). Species of Baltoniodus arc ically through a successionof similar, bio- distinguishedfrom thoseof Prioniodusby mor- stratigraphicallyuseful species in the Earlyand phologicallydifferent pastinate elements in the earlyMiddle Ordovician,and in rocksa couple two P positionsof their skeletalapparatuses. of zonesabove the one in which it first ap- Although this is regardedas of no more than peared,spawned a new lineage,assigned now subgenericsignificance by severalinvestigators, to Oepikodus(Fig.5.l4). In speciesofthe latter, others have pointed out that Baltoniodusap- the skeletal apparatus consists of Prioniodus- peared a bit later than Prioniodus and also like pectiniform elements;a geniculateconi- probablyevolved directly from a youngerspe- form M element;and a symmetry-transitionse- cies of Tripodtts and not from Prioniodus. ries of quadriramateelements like the one in However tbis may be, Baltoniodusis the uni- the Sd position of Prioniodus. versally acknowledgedancestor of Amorpho- gnathus, which appeared in a somewhat later part of the Early Ordovician and ranged, 5.7.3 Family BalognathidqeHass, 1959 lhrougha successionof distincivespecjes, to Beginning in Lower Ordovician rocks just the end of that period. above the ones in which Prioniodus is fitst rec- Speciesof Amorphognathus(Fig. 5.15),per- ognizedand extendingupward into Upper Or- hapsthe best-knownand most widely distrib- dovician strata is a successionof recurrent uted membersof the Balognathidae(Balogna- guotda$ ilqe snl"JEddv 'snor^qo lou aJ? sJolsecueJealc r sluauele I I 'os ua^o :..4EJquraurlco,,flrul 1ou pu" uorlrs JuDutauuosJo -od l I eql ur 3rgfuourp eq l(?ul snlEffdd?oql ddE aqJ sluop 'od"qs leplur?J,{d Jo sluourala (IIJoJ r uoBrsod1?q1 -ru?r el?.rq?loppue ^l,r\oJl"u 'elepedoruel 'olel? leuorl t_ Jo) ujJoJruoc -?p"r8relur,{llmrtoloqfuour Jo seuesS ue puE :IT PAIEIEJ SI II :suoDrsodI J ur slueuele el?uuodrqJo Jred E roJo lusdncco pue etErqelopJo ll?d p :uorlrsodd puocesaql @rS-Jo snl?Ed uI sessecordpolqnrquep oAu qll^r Eueu] r- Jql leJdJolur -sleet€uqspd o{qep?Iq:uoqrsod ^luod ouo ur sosset lslnJrlu9P? 0J? -oJdpalencquep earql qlh{ slueluoleoleuus?d E3[a alEurls?d epnlcur'(S l'S tuJ) mqpuStrlrout"g Jo sercads rq$. 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VINOOONOJ AHJ THE MAJOR CONODONT GROUPS 65 zll) symmetrical stuctureis, in many respects,more like that of rm") elements.In Prioniodus than Baltoniodus species,but the b our students, speciesmost proximate stratigraphically is an Ets characteristic unnamed representativeof Baltoniodus(Sav- me samplesthat ageand Bassett,1985; Orchard, 1980).Conse- s rhat resemble quently,in Fig. 5.11,Gamachignathus (includ.- h lack the plat- ing BirlIcriodus and.Pelekysgnathus in the Icriodonti- niniscaphate ele- dae,primarily on the basisof obvious sirnilar- E rom) thoseof ities in the Pa elementsformed by their species. bded in the Bal- Many of the other elementsof the apparatus ibstrated in Fig. are different.however, and the differencesare nhidae the mul- sumcientto raisereasonable questions as to the ir Ihiipfer (Fig. relationship belween l%iodella and its proba- d bl Bergstrdm ble derivatives and the primarily Devonian ;mn1m of Norr- Icriodus-Pelelqtsgnat hus complex. Thus lcriod- E ( 1982).Nei- e//a and its kin are here set aside as a new fam- dontina is welL ily, the Icriodellidae,the relationshipsofwhich ICRIODELLIDAE Er drscussion,al- are shownin Fig. 5.17. r rtan passingin- Basically.the icriodellidshave a quinqui- DISTOMODONTIDAE rticb is known membrateskeletal apparatus in which the Pa -/a/ lu *ere probably elementis pastinatein the apparatusofthe old- t!- be an index to est speciesknown, pastiniscaphatein thoseof t fruna recorded later forms, and stelliscaphate,with four pro- cesses,in apparatusesof the youngestspecies Fig.5.17.Silurian and Deyonian P oniodontida. hlctive typesof known. 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'salouuepJo s,{oJ elSurs " -EJ"ddeur suoqrsodW pue 'qd 'ed eql ot uErs qll{\ sossocoJdJouelsod pue Jouelu? lenbeqns 3nqteu6ossAto -sEI sluaureleueealeq esolcJoesn€J 'dsnc pprruEj,td '^qqnts ? s?q lueluele ?d el"un -eq oeprTlepouJleqt u D^luelrurs apouzl qlIlA pepnlxur -s?d aql 'paqucsop reJ snr]i Dnapoull Jo ser.eds s'[ slnDpad'esprluopolJclpue'eeprluopourol lseplo eqt 'tl61 'dJueH puu nooqaqs€ll 'urolls W -sIC 'e"p$opoucl eqt Auouls1no pelecJed e^?q -pul'l xoJaofi o apol./4 Jo snteJedd" eqt uI 1 eraua6eqt Suolu?sdrqsuonElar orteuetolfqd 'uoucas ssol' l?lncJrc ,{ ?Duesse JlqrssodJoJaqunu ? JlsJrpurI LI S 3ll ul Jo slueurela rrJoJruoc ele{nrrue8uou'el?lsot" &. 'snpoulolsr(J ,{q perdncco ,(lq?urnseJdora^\ suonrsod S (8I 'S ol ueql peuftss?s?q (986l)Joqcsrg pu?'e?pp 'fiC) sercedsstxDtotdats uI 'uonrsod ES aql uI -uopourolsrqeqlJo sebodssnou?A fq pourroJ sluelllele alErq?lop elelnJrluep,(lJouelsod lnq

VINOCONOJ 3HI THE MAJORCONODONT GROUPS

'te Distomodon- rsigned them to nber of possible mg the generaI hiodellidae, Dis- *b.e. Pedavis is Rlcriodellidae be- Etr elementsI as- riions in appara- . &.nnemanniais of its only L-m ro that formed Rotundacodin6 :Easoningis also Irz'rol&rts to this f its more char- l-r assignedto Pe- l=- Non-Paele- xiderably from s of Pedavisarc bidella. Distomodus ldements ofspe- ilto Distomodus Fig. 5.19. Elemenlsand appamtusesofspecies typical ofgenera assignedto the Distomodontidae. Rtorhose formed I lresumed occu- r are clearlydis- ftom Distomodusor some other genusof the theless,I indicate in Fig. 5.17 the possibility tEreric relation- Distomodontidae instead of from lcriodella. thal Pedavis,whose familial assignmentis not uodonts haye To my mind, the prominentlycostate elements all that certain,might be the point of origin of fuilarities in Pa that occupyS positions in apparatusesof Pe- Latericriodusand the lcriodontidae. rhis case,the darls speciesare equally difficult to derivefrom -lbn of Pedavis either the Icriodella ot Distomodus stock and 5.7.5 Family DislomodontidqeKlapper, I9EI may thus be regardedas the featuresthat dis- tinguishPelavis. Thus, if one considersthe re- Conodonts assembledhere and assignedto maining elements(Pa, Pb, M), similarity is Distomodus, Rotundacodina, and Coryssogna- greatest between Pedavis and lcriodella, and thushave abasrcally quinqui- or seximembrate that hasguided me in assigningPelavls to the skeletalapparatus in whichramiform compo- Icriodellidae. nentstend to haveshort, weakly denticulate or Broadheadand McComb (1983)argue from adenticulateprocesses, and the Pa and Pb po- comparisonofthe Pa elementsof Itte Silurian sitions are occupiedby stelliscaphateand pas- Pedavisand those of latest Silurian-earliest De- tinate elementsor their reducedderivatives. vonian Latericriodus woschmidti that the latter The latter characterprovides a link with other may have developedfrom the former by neo- prioniodontideconodonts and suggestsorigin teny.Although that is an attractiveidea, non-P of the Distomodontidaein Late Ordovician elementsin the apparatusof L. woschmidti balognathids such as Gamachignathusot (Fig. 5.20)differ substantiallyftom thosein ap- Sagi odontinq. paratusesof Pedawsspecies and, in the absence Thereis someditrerence ofopinion in the lit- of information on the ontogeneticdevelop- eratureas to the apparatuscomposition of DiJ- ment of the latter, it is difrcult for me to see tomoduskentuckyensr Branson and Branson how S elementsof the supposedpaedomorph (Fig. 5.19),type-species ofthe stem stock,and (L- woschmidtl)might be relatedto earlieron- this afects interpretationsof familial taxon- togeneticstages ofancestors in PedavtJ.Never- omy and phylogeny. The apparatusrecon- '1rJOJOUolue SSoCOJO -JolurI snql 'Suuodruocpug I lEql ecuepr^e uoqs /fia^ € eq ol suerursadspel?JFnllr I?JeAes puonnqutslp Jo ,{poq8ul,{{or8 pu? pquelsqns ur srEeddesJeql pue pus JorreluEeql 1?fFeelJ E uo pas"q/aou sr (986I Soqcsrg 'E e) sroqlo sr dsnc aql 'pueq Jeqlo eqt uo 'sluelxela.rz1l,1 ,(q poloddns pue JsdooC petmo^pE sarc -ouSosstto) uI 'pue ro elsod eql 1? dsnc eql -eds-ed,{teql Jo snlaedds eqt^q Jo uorlorulsuoc qllll 'el?gd?csururEosoJe snuet lsqlJo sar3eds -er 're^e,lroH'Woluotst(J lmrd{l e sE poloJd ,tq peuroJ slueuele Bd nq 'snqpu8sbppd -relv sl snrqnp DulpoJopunptrJI i(luo esues Jo sorcadse luoseJdeJslueuele asaql l?ql pelset Jo l"ep poot ? e{Er[ sluelun8J?s.uossddof -8ns seq uossddofslodeJ snoJeunu uI '.ffiq 'y461ur [qd:n11pue -np DurpoJDpunJo{Jo slueueJJed pJgrldurs Jeddef) petcutsuocoJ snleJedd?,srcua[4Jnl qcnur eql uro{ pe^uap uaeq e^?q ,{lrs?o1q3[u -u l 'e eq!^q Jo sluauodruoJpeuroJl"Iduou eq1 l?ql llos ? Jo ssocordIeJelel pedole^ep ,{Food ot esolc,fua^ ,(Ilm€oloqdrolu eJ?leql sluorx ffi e rllr^\ sluelueleuuoJrurlced el€u4s?d poJnp -olo uuoJrrrruJpopnlcur lnq slueur -er eft eseql'peqrrrsep uaeqe^eq (6I'5 AId) -ele uuoJrurl3ed peurJolqd^lluar?ddE .{u? pe{Jel e^?q snqpuSossttoJ Jo slueruole ed eql ol srrjsas'snpoulots!(I uI sepnlcureq qclq,ll .eup4uopoFcl ^luoeql '(6I 'S tld) (sepoqu) .flrqrp outpoiDpunlov Jo lcots luJls$u" s?leq lseqeqt 'uorurdofru ur usunlrs JeAuno,(Josnl?rcdd? eql l?ql setoueq 'sr pu" u?rJnlrsaqlJo pue oql ol se8uerDutpoj 'ler{unC'sssn}pJeddelueJeJrp elmb osr^ueqlo -Dpunpv ,{uetoeu,(q peqsllduIocce ,{q pozuopeDqc '$lcols epnuopoluoud tue 's$oqdJouropesdJo eldu?xe ue eq ,(?ur^lqrssodsuorl -Jeigrpo,1dl ur pedolo^epslueru -rsod o,{rl gsogl uI sluguola Jo uorlscurTdurrs-eIe d a]{]{-Dapolrrl ^lluapuadepur lpqt slse8itns s8uablJnt cqeueEol,(qd,(le^rtcedseJ'sluourelersroJruoc -uDl O toJ (516l) JedooJ ,{q pelmo^p? ouo el?uus?d pu" al"urlsEd eldturs oJe suoqrsod arll sEqJns uollJrulsuoJJrE lEql 'otdulexJJoJ E aarppel[ /$ol qd pue ed or{1(n osolq..lfrq'snpouotslQ Jecld^l 'salouuossddof 'uoDrsod d puoceseql ur luour g) snpouJl 'Jet Jo esoqtJoluecsruruer er? (6I q '49) mlqnp g -3le ol?qdecslllelse tnoqlrA\ ouo 'sI teqt '.{qd nnualo'J euJeu Jo snl?redd?eql ur slueuele lN pue S 'snpour -JntrJ pu? reddEIX,tq paprutsuo3eJAlpur8uo 'sluelx t 3ql roc -ols?OJo Iecrd& oq ot loot (6t61) srcuallinurl snpou.toiste Jo snlEJedde oql D pue 'sluelxele uossddef sercedseW 'snlqnp^OuelEdde Durpo1DpunloY sroJord(6/61) uossddof'suos€ar lere^es roC Frruoj l€ql euo ol le]lseJu" se/;t.snpoutolsre 'iJot 'ssunsJluopouoc u€unls qlr/t\ tJOrS snPouJJ IO -sq str uI olel^nuarcdd? pu? 5lcolua^\ aql ur AIr?elJe Suqeepsroqln? lsoru ,4qsrseq NW uo snporu - p{e aSlppolN 'snqpuz -orsro ol paraJeJuoJq s?q pu? suorlrsodI pelslnJrl qlrur?J -oJpDHsE pogrtueprfleurtuo esoql s? q3ns pu? s eql ur slueureleruJoJrrrr?J e\rI-snpouol I alqEu?^ leqleJ sluerxela ed pauuoJ 'rfue^opu?l'I oqt ur Jelel -srcrfua^ s?q qcq,{| 'resrwA' saptotltouS1nots ur @rsod Jeqlo aIUII e euol? elll?c qcrql( 'pJlqt eqt pug snqpuSotpog luouralaDlnurJo uollsrulsuooeJ td eql uI slueu :(0zpnlepoFcl) sr1.DpadJo i€oloqdrour eql (9/6I) redd?I) pue Icrrreg aql uo luepued @s ,tleJeur Jo peledrcuu? l?qt stuourolo aleqd?csrTlols-ep,{IrEelc sl 're^e,r1oq'astDatJoql ur oepDuop "d 'aE rqrlreunFul rnq Jeqtoue:DutpotnJ se pegltuepr,(lpurEuo -ourolsrq eq7pue snpoutolsr( qloq Jo srsoutu trE sluopousl ed& eqt Jo stueurelaed pedoJe^ep(qJu?Jq Iec -Ip s,rodd?D{'s rlnga 1DurpotnJsarJeds ruJoJ IlaueJal -rd,{teql) qsnqsrqlJo r{ruerqeuo ,l'q SldJo oqt se (/t6I) uosuergpue uosuErgfq pequcs ^lsnol^ lnof e uo peseq uEd ro^{ol eqt ur ..qsnq,,z se snpouolsl(I Bur -ep euo eqt qll lueureleel?qdecsrllets € uours ne5 .{q spuno$ -ueqc srql petpcrpure^pq I pedolo^opseAee -od d puocaseql ur sepnlJurtnq ,{qdJnw pue .snue8 peu?u -uq pra^es^q {rots eql Jo fuolsrq ,tF?e ,(Je^ eql roddelx ,{qpopn4suoceJ ouo eql ol srelncrued rydr1 snqtDuSol uI 'ueDJcolueA l(lJ?eeqt olur po8u?Jpue uEunl JofeIII slr ur l?lrurrs sr \a\l 'slsuatlJnlual plrd 01 Peu8lsse -rSoql Jo Suruur8eqeqt 01asolJ Jo te lnqop slr 'O JoJ snluedde a"Jqrrrarurxese pelqurosse uEdde o,trl :8€6I epeuJsnpou.totste 'paqucsap lsnf s? peaar^ 'pueq roqto oqt uo '(S/6I) redooJ '(snsuDdxa I :2961 'rellntl 'stuJruJleJlEr.ld?Jsll snqpuSor.poxg rewl) osuDdxaLD apouotpttJ qr uI pepnlJul -lplsel\-Dutport7l perdnccos"1{ uontsod ?d sercedsuuoJ aqt se (8961)peoJxed pu€ IIoJIN eql qcrq { uI snleftdd?^q plole{s el?Jqrueujrxes pequJsoplueuele et?unssder?zrq oql uoll l96l e qlud sercedsJo dnoJ8? s? 'sr terlt :61'5 3rd -rsod^q d egl ur sepnlculpue ol"rqueulnbulntt pI .illraDl 919 ur pelErlsnlllleuuEr! Jql ut snpourotste sl (tr6t) I pu? reddet) Aq petrruts '3Jd ^qtunI VJNOCONOJ AHJ THE MAJOR CONODONT GROUPS

Er illustratedin 5.7.6 Family lcriodontidaeMiiller lnd Miille\ follows but note that lcriodus in this senseis of specieswith a 1957 almost surely polyphyleti.c.^fhat is, I- angustus l|ls in which the and,I. angustoides.both wilh the segminisca- biodi na-like stel- Included in this family are Latericriodus phate Pa elements typical of luiodus, have Mtller, 19621Icriodus Branson and Mehl, beenshown by Klapper and Ziegler(1967) and l)igornodus made 1938;two apparentlydistinct goups of species Carlsand Gandl (1969)to haveevolved at dif- iDning of the Si- assignedto Pelekysgnathw '[homas, 1949,An- ferent times from different ancestors in s'enlockian. b In tognathusLipniagov, 1978;and an as yet un- Lateriuiodus. cock several lin- named genus, recognized on phylogenetic Serpagli (1983) has demonstrated that td this by chart- groundsby Sandbergand Dreesen(1984) and the apparatus of Latericriodw woschmidti, i the lower part basedon a groupof late Devonianspecies pre- founder of the genus,is seximembrate(Fig. i bush(lhe typi viously refened to luiodus 5.20). A bisegminiscaphatepectiniform ele- of the type Icriodonts are characterizedby a basically ment occupiesthe Paposition;a pastinate, low- ic-!Ls another built multimembrateapparatus that includesbi-, tri- pyramidalconiform elementthe Pb position;a aar anticipated or merely segminiscaphate pectiniform ele- more compressed pastinate coniform (or (Icriodellidae); i menlsin the Pa position.If thereare elements "acodiniform") elementthe M position;and a r along a little in other positions,they are an assortmentof morphologically intergradational series of Pa elements rather variable coniform or only weakly den- alale,tertiopedate, and dolabrateelements the -d ffi. as Hadro- ticulatedramiform elements. Sa,Sb, and Sc positions,respectively. Klapper Weddige and Ziegler (1979) advocate divi and Philip (1971),however. did nol recognize d la.ein i1shis- sion of Icrioduss.l. into two groupsofspecies, homologuesof the S-serieselements of .L. ancestralto one that formed bi- and trisegminiscaphatePa woschmidti in the apparatusof Z. Iatericrescens ;rcies-h Jeppsson elements,and onewith segminiscaphatePa ele- (Fig. 5.20),which they concludedwas bi- or tri- Epical of Dlslo- ments.For the first goup they usedthe generic membrate.Thus, ifZ. woschmidtiand L. l^ter' ae apparatusof nameLatericriodus (Miiller, 1962),for the lat- icrescensdid,, indeed, form part of a single lin- knt of thoseof ter, Icriodus (Bransonand Mehl, 1938).I fol- eage,a featurein the evolution of that lineage 'i rtre Pa and Pb low weddige and Ziegler in the summary that may havebeen the lossofS-series elements. Al- E and pastinate $. Phylogenetic posi- r,rhese two Fig. 5.20. Elementsand apparatusesofspecies typical ofthe Icriodontidae pedomorphosis, *t-\. Rotunda- E Silurian and is, /!-^/Jn rest|al stock of <$-<:/-{/-9,4 ' UVVV Co4'ssognathus Latericrioclus woschmidti d- These are re- fuents with a trs of a sort that | from the much Endacodina du- IDsson has sug- lsent a speciesof rnts formed by iiscaphate,with .ln Coryssogna- md the cusp is Itcre appearsin Dbe a very short EUnJoP sluourele eleqdecsrurru8espe \oJ-oeJql eql tueragp ol seneds snt4pu8st\alad Jo sdnoJa ^q \lnpad Jo^ldtu€ Azt Jeqlra l?ql ftelc suees /Aou 1r 'eld(IIexe Joc u?ruo^e(I etrl-elpplw pu? eql SuureJ 'pe^los FqerEJls eJour e eq 01 ur"rueJ ,{u38ol^qd pu€ -ar pelseSSnse^eq sJoqlne l?Je^es^lr?E 'de8 Jrqd€$ opouoJ u"unlls IUOPOUsrur SUJOIqOJdSnOJeUrnU 'elmrpur ^ruouox?1 ,{eru -r1eJlsaqtJo esn"33g serceds-ed&eqt'snpuq) E pJpeeu s{Jeu3J JOUd Se 'Je,\e,trOH ., SI$SOJxepur,, -ar d sepnlrur l?qt dnor8 ueruo^eq ote-l puz r4 E seop^p"q uEql ueruo^e(J s? snorx4 euo3eq a^uq sluopousr slppqatre urorJ de8 JrqdpJBrt?Jtsolq?r3erdd? u? I arour Jo sJe13e pu? 'serJEJorqu?ruo^3o Jele,{{-^\o uI ,{Wrr ,{q pel€r?des eJ?sarceds u?ruo^ec ,{lffg eseql "qs rrDpanpv tJtotJ -qd"r8q"Jls lu?Uodurr eJ€eEprluopolJtl eql 'suorlrsod S ur uorloes ssoJcJ€InJJD All"uuassa oqe\uap ? l€ql 'a"pquoPou3l eql Jo slueluela uuoJruoJ el"lnJruetuou pu? m JIlal,{qdouorq Jo Aolsrq 3ql ur slue^e et?l poreprsuoc i(0uec 'suoursod n (^lqeqord) pu? qd eqt uT^uu. slueur lql JJue,{o JEIC -er e^Eq (t86I) ueseero pue Sraqpu?s pue -ele (..u?urpoc?,,ro) ruJoJruor e1?urlsed'uorlrs ltrsJJue eql olul :snpou)I lo se?eelJlI ueruo^eq elpprw ur sulel -od ?d eql uI slueluele eleurul8es pe/t\or-gJ8urs Du op I alrq^\ -led tu?uo4nlo^e eqrrrsep (6161) relBerz plde qlr^\ sesnter?dd? pauroJ /I g '*J ar ,.snql ( stuetuele e8rppa^\ pu? (fr6l) oElppolN '.snpouruap-J -ou8st4apd,, ol pou8rsse serceds u?ruo^eo Jo esn?J Jo ,tuotsq eqt ur slue^e Jetel leq.{\euos peJeprs pue xaput 'd @BDupoT'J) snpou)l tsrg 'l"er8 ^VeE r.rrPad Jo esoql -um e^?q (r961) reltarz pu€ reddED{ :seqrupJq aW Jo peeqe IlaM, pue QtprLuq)sotl/. 7) snpou) tJo srrros sluolx snpou)J 2^\e^uap ot^7 pue snpollJualD7 ueru -uajoI Jo e^rlelueserdeJ lsJg eqt Jo p?eq? trq -ypluulJso^'7 -o^ec lserlJ?e ur suJeD?d crleueSol,(qd crs€q epll.l e \xapul dJo t[JoJ eql ur) usunlrs lselel [e ersqdecslltnq lno polro^\ e^?q (696I) Ipu?c pue slreJ eql ur per?eddE (0Z S 8lC) snqtDu8stuppd o{rE aloureJ eql 'sluSruuoJr^uJ13uoo8 ,, edpueJE,,u^\o sll oq ,tetu s se 'ttpluqJso$ -el euq€sredr{ri01 uonnqulsp Jreql ur pelculs lr lnq 'cqel^qd,(lod eq lou Kern snpoltJl t ar{l ur slueluele -aJ fpuer?dd? eJa,,rlser3ads uEruo^aq elrl o^\1 snqJ isluarlIalo olpqdeosrurur8es^luo ei\-snpouJl (u/(\oDl E4sqns sl eFql slr lnq lou en srulfiuSoJuy Jo suol4elzJ pardncco eJ? suorusod ed sesnl?Jedde ^q 0 Jq1 ur eur?seql puE urSuo aoleq Jo e^oqE tuo{ pe,&el^ s? eurl esoq^\ rn serreds l?rg^es peull.eds snqnuBsbl EE aql uI slueuj -lno ped?qs-J u? pue sesseJoJd -alad 'O861) uaseero pu? Sraqpups ot turproc ,,mlDu01stnopad I"Jel"lolelsod,4qqnls^llpculauruj^s? e Srull'uSotuy ul^out -c? 'ueq,tl u€ruo^ec ele.I aql ur Je{rrql ue^e ^erl I srueuola €d 0q1 ,(lJood eql Jo sluoruele ?d eteqdecsruru8es eurmoq told egJ srolsoru€ snqnu8sblapd ud pasIAePse,{{ 1l '(IleqlJo utoJJloa'snpou)J utorJ po^Uap ueeq e^€q ,4Brx loJol I pue peeq ouo roJ elq?I?A? .{nuoJedd?sr (6161 '^e€eC) snrypuSsblapd Jo ser3eds euos lsEol te leql NJloau 3ql preS snpoUahl)nog'$Icols luopouJr e8?ls-elEl slse83ns1r esn?coq'asJno3Jo 'Sum8ulur sr srql 'slueluele Pepnlcur eq flq? osaql JoJ sarlI?u cueue8 .reu eleeJc 01 elqelrs d-uou Jo € reJrurrs? saq 'sloor lo |JlotJ st^Dpad -ep eq .{letEurrlln fl pFoqs euo lsnf lou 's,,!lor JeSuno,{ lEq^leuros ^€ur peluesoJdor '?,{Zr,rJ I mJsrq9l 'sl,{rp olcrluep aarqt e^?q lnq 'el..\-s|qtDu8sblalad snqwu8sllalad lEqt polou feql ..'ruro;rur e se llplLuqJSOtA oJ? 'sal3edsoseql Jo lsoru JoJ u^\oDI seuo -po*,, are qorq^\ Jo II? lou 'slueluela uJoJruo3 ^luo uofol I pu" pEeq eql 'slueruele ed 'snqpuSst4apd urqtl,{{ sa8€e elq?u?^ ,(HArqJo dnor8 e 'u^\oD[ szpo?.rrl lse E[ul eql s? (a"p -ul[ lueJeJrp o^u ur sJoqu]orrjpue eq 01 p€els -plo e\t'rlSDupDq 7Jo sntpr?dd? eql uI popnlJ ,opunjov pepree -uI lq8noql rlrq snpol.tJl ot peu8rss" ,{pueunJ -ul (LL6t) tured pue uoueueqC 're^e^{oH puz 4ptwqlsottr seroedsueruo^ec alE-I a^S Jo dnoj8 ? Jo Joq 'sluetlIala rlJoJruoc IupnuEJ^d ro elEunsEd,4un f, sewJ?des 13ql -rrJorrreuo Jo snl?Jedd" eql ur lueruale (..uuoJ ,{Ilsou]Jo lueuruossB uE pu" sluoruola?d el?qd PFO.{I l"ql suourl -quopolsro,! Jo) ruJoJruor elpln rue8 e pegD -etsrunx8ss Jo pels$uoc tunsanualDl sflportJ q snTlDu8st4aPd -uepr osle e^eq (t861) uosaalo pu€ Sreqpu€S -ua1o7 Jo 1eq1e{I 'serJedssnpou)l Jo snteJed ol nsuas snpoLtJJ 'uBrcr^opJo oql u?ql Je8uno^ sIJoJ ruo{ -d€ eql l"ql eeJS?sroqln" Jaqlo lsour 'snpol.tJl i{ pu? ledd?D{ pauoder eq 01 eqlJo euo 'luerueJo(..rrrJoJrl snue8uroJ eqt peseq(8[6I) IqeI pu? uosu?rg ^\eJ 'uleueS -uopolsro,, ro) uuoJruol el?lncruot e sapnlcur qclq^\ uo sluerrJele eleqd?csrurutos oq1 Jo '31{) t Jo sul8uo 'oslv os[? 'dnoJ3 u?ruo^ec ol?.l-elpplhl eql Jo Jeq .tlerrluo peuuoJ (02'S srrleredde snpouiJ ueleJrp l€ ,tlluep -ureur l?Jtua3 pue soDeds ed,& eqt'(02'S '8lC) ue pelEco^p? (Zl6t) IouAIng q8noqllv c\ KPI0Jsu.llDu8 snpulput dJo snleJ?ddEoqt 1"qt pouodar ues '?teuei- $uatllels aFqd?c -oerc pue SJeqpu?S'ra^e^\oq '.t86l uI uorleJ? lueJe.Up ol serceds ol/\l eql AuuErss? eJnt D pagrluepr ueeq -des qcnsJo uoddns ur ecuepr^eorSoloqdJout -cellqcJ" snleEdde ur secueJeJrp esaql^q ezru " to salcsds qJIq/'(\ alDrTuaeq s?q eJeql '^nu$el lnun 1nq ereueE -8o3or ol elq€leJeJd oq lq8ru lr '^le^uuulet

VJNOCONO] EHJ THE MAJORCONODONT GROUPS '71

* hasbeen little which species of luiodus have customarily 5.7.7 Family PolyplacognathidaeBergstrdm, EI of sucha sep- been identified or the single-rowedsegminis- 198t dberg and Dree- caphate elements taken as typical of Peleldys- I-ate in the Early Ordovician a speciesof the P. inclinatus gnathw may have been produced indepen- Amorphoqnathusgroup (Balognathidae)was -ol d centralmem- dently at different times in different lineages. apparentlythe progenitorof a stock of prion- group, rian also Also, origins of the family are by no means iodontide conodonts characterizedby a re- "oistodon- I lor certain. duced, bimembrate apparatus of bilaterally ;r ro b€ reported Klapper and Murphy (1974) suggestedthat asymmetricalstelliplanate and pastiniplanate Ldovician. Icriodus sensu lato mlght have evolved from elements.Recunent groups of such elements $ har-ealso iden- Pelekysgnathusindex, but they found no spec- are the basis for recognizinga successionof "oistodonti- {c imensthat would bridgethe gapin morphology speciesof Eoplacognathus(Fig. 5.21). These ts of one mem- that separatesPa elements of Lateriuiodus specieshave been of considerablebiostrati- (1982) L- onian species woschmidti and P. index. Nicoll re- graphicutility in rocksprimarily of earlyMid- r hrr thought in- gardedRotundacodina dubius (Distomodonti- dle Ordovician age.The stock seemsto have io differentlin- dae) as the most likely ancestor,and Broad- died out, however, early in the late Middte h elements,the headand McComb(1983) regard Latericriodus Ordovician. lese species,are woschmidtias a neotenousderivative of Pe- During its early Middle Ordovicianheyday, E rhree denticle davis. Fihraeus (1984) suggestsderivation of Eoplacognathusseems to have giyen rise to an presum- timaely be de- Pedavis from Distomodus, in which important line ofspeciesthat Bergstrdm(1983) rmes for these ably he included Rotundacodinadubius. I re- refers to the genusCahdbagnathus (Fig. 5.21). Bouckae odus gard the neotenousroute suggestedby Broad- The bimembrateapparafis of Cahabdgnathu\ rrarlable for one headand McComb (1983)as unlikely because lrke thai of Eoplacognathus,is composed of a it was devised primarily to explain the origin of pair ofstelliplanateand a pair ofpastiniplanate poorly ls of the the Pa elemenlsof I. woschmidlifrom thoseof pectiniform elements.Howeyer, those of the posterolateral b- Pedavislatialatus, and it thus ignoredother ele- Cahabagnathusapparatus form mirror-image $ T-shapedout- rnentsin the apparatus,which are surelynot pairs, whereasthose of Eoplacognathusare bi- &s'. Origin and the samein thetwo species.On the otherhand, laterally asymmetrical and have more simply I tnown, but its there is substantialsimilanty betweennon-P ornamentedupper sides. : apparentlyre- elementsin the apparatusesofR. dubiusand L r hlpersalinela- woschmidti,as Serpagli(1983) has shown,and the remote ancestors of R. dubius certainly Fig,5.21. Elementstypical ofthe apparalusesofspe- lfe s olked out built scaphateelements comparable to thoseof ciesassigned to genemofthe Polyplacognathidae. r earliestDevo- L. woschmidti.(Of course,the scaphateele- titanjte lcriodus ments someof them built wereeven closerto [fti7) havecon- those of Pedavis,which I ally to Iuiodella be- il rhe history of cause of greater similarities in M and Pb r) ard Weddige elements.) Dlulionary pat- While I do not claim to have specialinsight 4x of lciodus; into the ancestryofthe icriodonts-or eventhe [984) have re- clairvoyancethat would be requiredto makea i the history of monophyleticunit out of this family-I suggest that a derivation of Latericriodus woschmidti la-ol stratigraph- from Rotundacodina dubius explains tlte char E biofacies,and acters of more of the Lateriuiodus apparatus r as Devonian than doesa derivation from Pedavls.Pending , prior remarks badly needed additional information on Iate :ms in icriodont Silurian conodontfaunas, I submit that this is in to be solved. a more straightforwardroute than is the oneby br that either way of Pedavis,whose own origins are yet to be tre elementsby amDlvdocumented. 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VJNO(ONOJ IIHJ THE MAJORCONODONT GROUPS

whosebest-known species has a bimembrate specieswith apparatusesin which the Pa posi- apparatus,was probablyalso derivedfrom an tion is occupiedby an angulatepectiniform ele- early speciesof Neomultioistodus(e.9., N. cly- ment (e.g.,P. tenuis,P. florida) becauseof the paas)by simplificationof elementsin the P po- often repeated observation that, in large sam- sitionsand by lossof elementsin the M and S ples from a successionof late Middle Ordovi- positions. cian populations,the denticulatedlateral pro- Lower Middle Ordovician (Whiterockian) cess of the 'dichognathiform' Pa elements strata in North America also yield two recur- rotates gradually anteriorly and ult.imately rent groups of dominantly hyaline elements fuseswith the short, adenticulateanterior pro- that are identical in plan to those by which I cessto producean elementin youngersamples recognize speciesof Pteracontiodus, Neomul- that is formally angulate.As Bergstrdmand I tioistodus, and.Multioistodus. but with shorter noted in 1972,this sequenceof eventsresults cuspsand longerprocesses, which bear numer- in a type of apparatusthat is basicto the ma- ous white denticles.These groups record two Jor group of dominantly post-Ordovician closely related speciesof Paraprioniodus (Fig. conodonts herein identified as the order 5.22).The olderspecies (P. costatus)apparently Ozarkodinida. had a geniculateconiform elementin the M po- Becauseil is unfortunateto have a major sition of its skeletalapparatus, whereas the M evolutionarystep such as developmentof the position in the apparatus of the currently Ozarkodinida buried taxonomicallywithin a unnamed younger speciesis occupied by a genus,I suggestthat Plectodinabereserved for dolaUrate(or "cyrtoniodontiform") ramiform specieslike P. aculeala(FiE.5.24) with pastin- element. atePa elements,and that thosespecies with an- Pteracontiodusrznges, in the form ofat least gulate ;Eas of generain- Pa elementsbe transfered to another lfueDb at top of one unnamedspecies, into Middle Ordovician genus, which I will identify here only as I- aid P elements. rockswell abovethose dominated by the other "Plectodina." membersofthis family, but apparentlywas not The problem with Aphelognathusis just the ancestralto other conodonts.Dzik (1983)re- reverse.That is, the type-speciesof Aphelo- species haye ported that, in a manuscriptthen (and still) in gnathushasan ang)latePa elementand is thus b-- most authors preparation,he and I might consider Pcra- appropriatelyan ozarkodinide (instead of a tiaisodus (Fig. prioniodus, a Pteracontiodusderiyative, as the prioniodontide)conodont; the two specieswith qls of the type- ancestor of the important Ordovician Phrag- pastinate Pa elementsnow assignedto this anlv lacked an modus.Forvaious reasons,however, that now genus(1. gigas,A. kimmswlckensls)will need q be a reduced seemsunlikely, and Phragmodusis shown in a new genericassignment, or can be E\eomultiois- accom- Fig. 5.17as a possibledescendant ofan as yet modated r rFig.5.23), temporaily in Pleclodina. Thtts, in unidentified speciesin the Tripodus compLex. Fig. 5.11,I show the rangeonly of Plectodina sensu stricto. Species of " Plectodina" and. Esj apparatus Aphelognathuswith angulate Pa elements of 5.7.9 Family Plectodinidae,new are ! llulrioislodonti- included in the ozarkodinidefamily Spatho- In this new family I include prioniodontide gnathodontidae,whose content and strati conodontswilh a sexi-or septimembrateskel- graphic distribution are shown digrammati- etal apparatusthat includes a pastinate (or cally in Fig. 5.36. "dichognathiform")element in the Pa position, PleAodina s.s. (in the form of P. acalea- an angulatepectiniform element in Pb, a dola- /orZes)almost madeit to the end of the Ordo- brateor bipennateelement in M, and alate,di vician, and specimensrepresenting a host of g).rate,and bipennateramiform elementsin variable (and largely undescribed) speciesare the Sa,Sb, and Scpositions, respectively. common in samplesfrom low- and intermedi- Sinceabout 1969I have assignedconodonts atelatitude Middle Ordovician rocks. with such apparatusesIo Plectodina Stavffer The Plectodinidaeseems also to be the best and AphelognathusBranson, Mehl, and Bran- home for Scyphiodus(Fie. 5.25),whose only son,taken in a multielementsense. However, I known specieshas a unimembrateskeletal ap- havealso assigned to thosegenera a numberof paratusthat consistsof an anguliscaphatepec- (eeu4uopoluou,{J trlwluo[lg Jo aql re^o .tluol.ld lEels s"q pos?q FJo 3c?JJelno ,tlrueJqnsse'696I) ss"H tr uo eep ,tlFu?J ^nq^q {snJ aql Jo eceJ -rluoporuor^c eql 'snpouSDtqd Jo r.I)J aql ur ,44set u^uou^s elqeqoJde smlt s\ snpotuotti) 'sn|Iu rI lEql euo uloJr -8oc mpoutSotrq410 slueurele t{ oql tuaseJdeJ doliqd poc?ld leql sueurcodsuo psseq Klqeqordset' snpotuol to auo sru\u8o) -rdJ snua8 ruJoJ s,JeJnsls Jo serceds-ed^laql rl'snpolLtSolqd esneoeqfJ"ssecou sr srqJ 'e?prluopouo!^J pue I Suaurele qcns ,{IrrreJ eqt ot DutpotuoLtg snpou]Sotqd I ro Jrleueeoluo ?raue8eql JaJaJeJer{ I '^lsnouels,turl"q^\ouros aq pu" F louuEJ 696J'ssoHaDp1uopotuout) qlu0l 0['l'9 Ens?d eql tuo{ E{a rrrjoJrurlced ds Dulpoluqitg 'snlBJ?dde m aJE suou$od olerqueurun 'pecnpal dole^ep ol auo " ^luo tuatIIelo ,,urloJrl er pue luollIala u[oJrurtced psurroglqd | 5lq qcnur tueA € dolo^ap ot (snsoutot snlpu8nD4tlod setn uals txJOJIlIl?J reqlo eq1) u6uo uecuelllv qljoN Jo sluop ',{uetoluo uI 93qs el€J s^{ol^ Jeddn pu" -ouoc epuuoporuoud o^{l Jo euo e Suquesolder slueuralS Ed Jo Iulel€J J'ePplluoPoluol ele sern8go \l JoddneqI 'solltuue cueuoS9Jdnsol enlc DutpoJ -Jedd? se,!\ snulud snporydtzs^Iuo sur8uo eleurl^llue bC'S ArJ) Iedrcuud oql sr oiBls Is'luoudolo^epslql l€ slueueleJo r:u auos qlr^\ -sed Jreql IJ?ur ot lesJo lzurpnlr3uol lq8ls aql eJnlsueleuqsed eqJ a8e$ a$ougSoluoIIJEo fuo^ e 8uI IXrOrq3OJeleqse ,(luo urplar s$otdj,alesnporqdhs oJntEU sngl -tuoserderlueuele ueJo sr oJn8gJe,,rlo.[ leeplulpopold) sntuud snpotlldbs lo lpcrd,{l sluouele ea 'SZ'S 'Eld vrpoluoltd t oqs 'sat?ls crlouaSoluo Jelq,{le^rssecJns Eurluas l[p lou ,{lqsqord -eJdeJslueuale ur ecsel?ocsossecord Jouelu? r sr Brauat eeJqt pue l?relq l?ql lnq '(..uuoJrq1eu3oqclp,,Jo) al? efupleJo ,{pnlsluecar E uI 'squ ,{lasre^suerl ^q r Flale{s eql Jo -uq.sed eJ? se8?$ qlrnor8 ,{Fee .{re.t 8ut paDJuuoJsJlorluepJo s^\ol IJIIETBdeelql sJEJq ^lJ?ep '(2861 Ftrq erour suJaes -luasJrd suaurrJedsleql perJ^oJslpl leql ql8uelerrr?s eql lnoqeJo ssecoJdroualsod d- uo lueurluoJ '1oeas) ?toI?C qtnos Jo uoueuuod Sedruur^\ e ruo{ tes.Uo,tpqttls st 1eq1ssac guneJ eqt rrjo{ sluetud:elasnponldtJs Jo uoBcouoc -oJdrouelue ^lleurpnlduol eTlepBlq qlt^\ luourelauloJrurl luopouoc " etBurrrJop qJrqnA k puE e?p4uop 'sluouola pd pue'qd 'I I 'cS 'qS po,{olloJ'lq3u uo sluouleloeS (eEplluopouou(l) trtpoluDitg ptJe pald pue snpout snporuS1,trld pu9 '(eEprupotceld) ,??porrald^q ol psu8rsse sorcodsJo lecrd^l sesnleJ€ddEpue sluouolg 'tZ'S 't!d €reg Z/6I uI t ur dsnJ eql paes Jofu ur e sI qcrq^\ Dod PelslncuueP I ro auo uo elsoJ qlIA\ ilsnc l?urur I ted-'(l oleuuadrq rlJur r{crq,{\ 'ra1 p slueluale rrrJoJ ql .{q suo4rsod s lnJrueSro (..rrjroJ , r uoDrsod I I Jrp,,^q Jo) eleullssd ql qJIq,{ ur snleJ rp e sEq 's€un?J {I^I opnln?r.{\ol I snpoutSorrld 'I861 uI urorls pou3?rqd ^JrueJ VINOCONOJ IIHJ 9L THE MAJOR CONODONT GROUPS

family Phragmodontidaeeslablished by Berg- eitherdeveloped by phylgeneticreduction ofan strtimin 1981. orginally pastinate form, that reduction is not Phragmodus (Fig. 5.24), characteristic of documentedby extantcollections. low-latitude Middle and I-ate Ordoyician faunas,has a distinctiye seximembrateappa- ratus in which the P positionsare occupiedby 5.7.I 1 Family Rhipid.ognathidaeLinhtriim, 1970 pastinate(or "dichognathiforrn")elements, the M position by a dolabrate(or "cyrtoniodonti- ln the Treatise Bergstrom assembledBelg$ro- form") or geniculateconiform element, and the emognathus,Appalachignathus, Rhipidogna- S positionsby the "phragmodontiform"rami- thus, Carniodus, ar^dHistiodella in the Rhipi- form elementsdistictive ofthe genus.The lat- dognathidae,which was assignedto the Prion- ter, which include alate, tertiopedate,and iodontacea (the Prioniodontida of my tax- bipennatetypes, all have a terminal or subter- onomy). Following publication of new infor- minal cuspwith smooth sidesor with a sharp mation on Histiodella, which I have cited in costaon one or both sidesand a long, arched, Section5.7.1, I feelrnore comfortable assigning denticulatedposterior processat the crest of that genus to the Oistodontidae.Also, Car- which is a major denticlethat may rival or ex- niodus is out of place here,because the sexi- ceedthe cuspin size. membrateskeletal apparatus ofits only known In 1972 Bergstrdmand I included Pirag- specieshas a pastinateelement y/ith threedis- , end Phragmodus modus and Plectodina in the family Cyrtonio- tinctly processes position tlnenrs denticulated in one P dontidae and speculatedthat these genera, and an alateelement with a long, denticulated which dominate Middle and Late Ordovician posteriorprocess in the Sa position. Because from the conodontfaunas in the North AmericanMid- neitherofthese characters is a featureofthe a[F r-!Ls Dalota (Sweet, continent, originated rn Pfioniodus. lt now paratusof any other rhipidognathidspecies, I irns represent- seemsmore likely that the prioniodontideplan feel that Carniodus should be reassigned.The E clearly pastin- of the skeletalapparatus in speciesof these only prioniodontidegroup in which Carniodus a liat lateral and three generais indicative of a common, but could be accommodatedis the Balognathidae, I dements repre- probablynot direct,origin. Thus,in Fig. 5.1I I but thereis little morphologicresemblance be- bFnetic stages. show Prioniodus, Phragmodus, and Plectodina tween most of its skeletalelements and those Ets retain only as heterochronousdeiyaliyes of Tripodus. formed by typical balognathids.Furthermore, r mark their pas- With somereservations I alsoinclude Bryan- Siluian CarnioduJ is separatedfrom the Or- ir.i was appar- todina (Fig. 5.24) wtth Phragmodusin the Cyr- dovician balognathidsby a considerablestrati- irdontide cono- toniodontidae.Bryantodina has an array of graphic gap. Consequently,I follow Bischoff rtir (the other ramiform elementsin S positions that look (1986)in assigningCarniodus 1o the Pterospa- r) ro develop a very much like the distinctive "phragmodon- thodontidae(Ozarkodinida), whose numerous and the tiform" elementsof Phragmodus.However, P Silurianspecies built apparatusesthat included ..-trl unimembrate positions are occupiedin the apparatusesof strikinglysimilar P elements. Bryantodina speciesby carminate and angulate Generathat remainin the Rhipidognathidae pectiniform elementsthat are quite diferent include specieswith tri- to septimembrateskel- from the pastinate P elements ol Phragmodus etal apparatusesin which P position(s) are oc- t HasJ'1959 and cannot be shownat this time to be either cupied by structures that are fomally angulate crefer the genera ontogeneticor phylogeneticmod.ifications of or carminatepectiniform elementsbut are al- t to the family suchelements. In favor of an associationwith lied morphologicallyto the "acodontiform" P tEssary because Phragmodus,Inote that in the apparatusofP. elementsof Tripodusand olher slem pfionio- bm genus Cyr- cognitus one of the pastinateelements is re- dontidesthrough possession ofa distinctrib or r specimensthat placed phylogenetically by an angulate pectin- costaon the outer faceofthe cusp,which may ttrugmodus cog- iform one that retains a clue to its pastinatean- be markedon the basalmargin by a conspicu- &ble synonym cestryin the form ofa riblike offseton the outer ous boss or lappet. In short, those elements t Clroniodonti- faceof the cusp.No suchofset ornamentsthe may be regardedas very simplepastinate ones, D- as subfamily outer faceof either P elementin the apparatus in which no sharpedge or denticulateprocess rirrin over the of Bryantodina typicalis, however; hence, if ever deyelopedalong the anterior edgeof the ? pu? sessecoJdl?Jolel pel"Fclluep ,(lalnulur -StqrDloddv Jo srol.seouv (92'S Brd) senSoloru 'uoqs e^Bqslueuodruoc rujoJrr.u?J eql qcrq^\ul -oq JEaJJos[? Jru eJJql qcrq,,trul euo lnq'snsuat seuoss ue pu? :s$coJdJouelsod el?Inclluep? -xa snqiDuSoluaoltsStag Jo letlt u?qt eleJoqele u? qlh,r 'sluetuelew (ruJoJrluopolqro) elaq Jroru sr leql snl?ndd€ JEtalJIs? sEqsnqlouBltl) -?lop :,.ruroJruo1,,Jo 'pelsl^u ,(lsnontrdsuocsI -olDddv Jo setoeds u^iou)l puE 3d,{1 eqJ qsrq/{Jo euo 'slueuraled uJoJrurpadelqnEu? ^Iuo '9es qlr,{ 'snl"J?ddepleJa{s elEJqluolulxese sBq 'trC ur pelE4snllreJ? qcrq,{rJo sluouoduoc eqt 'otoalnJo 'd 'uopouad Jo sal3ads-ed,4ter{I 'sq"J?dd? aleJquleuul e lou '4?Jqlueuues 'saurllueJJ.urp lsq,rleuos tuo[3 E JA?gol pere^oJsrpuaaq oslE seq's{Jol uEu pe^Io^e tpqt {co1s uercr^opJo -n S-plur rno+ pu" 'ueDU^\ sEA\Ldox asuDatJ ^Iluonbesqns{IJ?g ellles oqt Jo sogcu€rqtueseJdeJ eJeueg eurg eql l? essc eql se^l u?ql EJuerIIv qloN o^\t eqtJo sercedsl?ql (€86I '4zq 19461'uo.rt Jo usrcr^oPJo olpprl^I eq1ur J0^1olqcnu Illo{ -Jq'I) serpnlstueceJ rrro{ suees u esnEo 'EurqJ u?rcr^opJo re ro'I eql uro+ Jo ^\ou -aqlnq 'snue8Jeqlre 'uo uoB?ruJoJur^lelrl ,{\eu crseq peloder ueaq seq qcrr{nr 'snqpuSoptdtqY Jo 'qllxi ecuouedxel?art e^EqI esn?ceqlou 'flr 'sJssaJoJdpolelnJn -ureJ eruss eql ur pePnlcur oJeqal? '^la^Ipads -uep '!oqs pue dsnt pullslp e qtl,{ -eJ 'eEpuuoporuou^Jpue e?prluopolJedeql (sluaulelo^lSuusdsqS pu? d Jo) luauale peaoq € puE ot asuoatJ eql ur peu8rsseere,{ qcrq^A'(LZ S :ssocoJdJouelu" pel"Fcrtuop 'tuol s seq lnq 'Arc) Dulpo4lozo.trlI\t p'de (17,9 'EIJ) uopolnd seplluep Jouelsods{J?l t?ql luauralen el"u -uedrq€ :ssecoJdJouelsod ? slcel lEql lueluele aDplluopouadqtwD{ 016I'tuoltspulI ZJ I'9 ?S st"l"'ot"rxl"d'pessoJduro3 -u? u" qlh{ 'snl?l?ddE eleJqujorllul^lJouelsodolel ,( ecrseq " 'l I'S '3!J ur lEllsecues" pagpuepleuo s?q '"urqJ Jo uercr^opro re,,i\o'I oql ujo{ oslB eql sr lr os 'el?ujrxoJdlsolu u^lou{ '(92'9 'ali) snqlDuSouao4stuag ^\ou snue8eqt sr tEql 1nq'ltaotssnqlouSopldlqf, ^lJecrqdE$nellseql ('eEpnuopoued oql 'dsnc Jo Ued u/$ou[ ur snor^qo lold eJesnqJou uI slsue 'esJnocJo 'uoD"nlls relrurs^lllu?J y) ^uE

'sluetllole sd puE 'qd 'I I 'cS 'qS ,{q Uol or p5^iolloJ lq8u uo slueu -ole eS (tt6 I ) T to rrl .o.ll:saJeg$otJ sn|puSlttJDtDddv Jo esow '.(t L6 I ) rF"d$S wot! sn|louSouautcSog Jo sanr -3rl eepqleuSoprdrqxeqlJo EJeuotFdrcuud oarql oqlJo sorcedsJo l?crd& sesnlerEddepue sruouelg '92'S'tld

sntltauooutaorrs6taa

'sluouelew puE rrllo] 'ed qceouI ol peu3rsse^roJsoroads Jo lslu'rralg lZ'S'8lf,

or-dsuoc pu€ JoPL$ {nJruet urnurlxEur s puE 'passeJduoJ rud rouolsod 6uol

YTNOOONOJAHJ 9L THE MAJORCONODONT GROUPS

long posteriorprocess that is arched,laterally ers. The stratigraphic(and probably phyloge- compressed,and surmountedat the point of netic) predecessorof P. aculeata,P. flabellum, maximum geniculationby a denticle that is had geniculatecon.iform, not anteriorly den- wider and conspicuouslylonger than the oth- ticulatedolabrate elements in the M position, and the ramiform S elementswere apparently neither so profuselydenticulated nor so con- Fig, 5.27. Elementstypical of the skeletalapparatuses spicuouslyarched as those in comparablepo- of speciesassigned lo th€ PeriodoDtidae.Top elements sitionsin the apparatusofP. aculeata.An even in each row Pa, followed downward by Pb, Sa, Sb, Sc, older speciesof Periodon,which has not yet and M elements. beennamed, is representedin the Proteusand Eleganszones of Jamtland(Ltifgren, 1978)by adenticulatealate elementsinterpreted as oc- cupantsof the Sa position and by adenticulate pastinate(or acodontiform)elements. The lat- ter, and the "tortiform" angulateelements that evidently replacethem in the apparatusesof youngerspecies, are the elementsthat indicate that Periodon and the Periodontidae belong in the Prioniodontida.Ofcourse, the distinctiveS elementsofP aculeataar;ld P. Srazdri,the spe- cies of Periodon that I know best, are also geD- erally similar to thoseof Phragmodus,and this ilEathidae. Fig- led me in the heydayofform taxonomyto sug- l.L I 1974).Sa ele- Eestlhat Periodon might be an older name for Phragmodus-I no longerhold sucha view. Speciesof Miuozarkodina, such as M. fla- t hown part of bellum, tbe type-species,have quinqui- or sex- lhr is the genus imembrate skeletalapparatuses in which the re- so it is the roundedanterior margin of pastinate(?) P ele- ? 5.u. ments is not developedas a processand the short, anteriorlydeflected lateral process com- monly bearsno more than a singledenticle. M fulstrom, 1970 elementsare geniculateconiform structures, arkodina (Fig. and S posirionsare occupiedby alale. tertio- | fu Treatise to pedate,and bipennateelements with a long, i:donlidae, re- straightposterior process. I the same fam- According to the vielvs just summarized, Fience with, or Periodon ernergedftom roots in eady oistodon- E_cenus,but be- tid populationsby developmentof a highly rr studies (Ldf- differentiated skeletal apparatus in which pro- Ecies of the two cesses of component elements gradually tt€ same Ea y becamelonger and more conspicuouslydenti- d subsequently culated. As in the presurnably ancestral Oisto- dontidae,P elementsnever differentiatedinto i P. aculeata, conspicuouslypastinate structures, but S ele- 4Daratus, with ments becamedistinctively arched and denti ts. one of which culated.In Microzarkodinadevelopment was ftiform"; dola- apparentlysimilar. but the posteriorprocesses ments, with an of S elementsare not arched,M elementsde- i end an S series velop no anterior denticles, and the feature I hts have short, interpret as a lateral processin P elementsre- ;rocesses and a mainedshort and bore only a singledenticle. : Jql 'luaur lnq 'esrUlp ot Jo sepnuep pue dsnt Jo suorEeJ -uoud JofeurEuour? suoqElar pereJur pu? uorl osle sI hEcrseq plxe eql ol laqlre peuguoc'sel'eds I?JoAes Jo -nqutsrpleJodrueJ 'eEe t$seul lsalElJo$lcoJ ? aql 1?q1spe^ slueurelaur 'pup lunoru? Jourur l(luouluroc ur sFssoJs" punoJ er? pue eepllolopuoc aql -sPruQoruo Jo ) d sr rel"ur otrq^\ pue :e{qEod pue elercsp ,{[?c ur pepnlcu ar? qorq^{ '(D a|ts!W) ?luopouoJ sleq fuePunoq -qsuepa?qc eJB selcuua(I { ecrSologfuolu aql Jo sro^r^Jnslsq eql oJ" tse8uno,(s1I :(eep #ns ol uelsl FuorlepaSrelur puE 'ezrs ellles eql Jo 'lnols -qteu8ojrqC) uopoJuDttg ol pau8lssBsurJoJ ldt snql Pu? eq ot puel snteredd?eql ur slueualaJo sod l uErcr opro ,tF?g eJ" se^rlsluoseJdoJuaou)l I ruJoJIs ue^osJo xrs y'suoursod o.trl oql uI slueur sll 'eJeuoE pu? sar[ueJ sepnltur 'rer.{8lP d lssplo It s ?qlh\ snl sdde -ele el"r^Erp uloJrsuolxe o^Dcurlsrp ,{lqEq ?prurporuolrdaql 'pe^recuot os sY'eplurpol P '(..uuoJrqleu8 sepnlourpue slHqureruDdesJo -rxes sr l?rll -uoud lapro aql rIlJoJol pourof eJerleJ? qcq,{r gEeddE lueurele snleJ?dd?crpqdec pezrlaeuru ? ,(q pozuep? '?aieuolopuoo pu? Be3"IlepleqqrH serlrueJ rql 01uSrsse d I -Jeqc eJEBprurporuoud repro 3r{lJo sluopouos -Jednseqt ur pepnlcur eJe,yuquoferuE lnq '?pn .^q r(lF€ulFdspr 'pecnperro 'petdep?'poglpolu ,(gzrcsdsueaq -uoporuoud eql ot sror{lne asrlDatJ Aq petfits busrp sr 'ser3eds a,req sesnlereddel?telels Jreql se ldecxg -s3 eJo^reJoq popnlcu sluopouoc aql Jo v ;Z'S'8rJ) redooJ '82'9 ^\eJ dorq aprmfue,r '3rg ur pezuerurunseJe slcols crJoueteprurpor 'Gplulpoluolrdaql 8'S rro f,lJEgeqt ur ^roN Fmtunse "prul [? lsour eql PUB ql 'uopnuoltg 'eprurporuoudtr.llJo serlrueJ puE aeuao .82.9.t!J ,t6t'lqaAt D filwDt t'8's ]VOIHlVN90AIHJ o a r" reqloJo esoql rar^ tnq '(V o I uI pue)^u uotssno q ol ldueu" ru/'\ I olouroq leql trFs s r suoqrsodlueJeJ uela elq?J?duoc [Ip 'uosEeJsrql r.{s e^R" Jesuoo r lEql esoql pue o EXIISIo UrlOJrr[EJ drssE sluaurele 5 lr,rq .{toloqdroul ) I prl sr'ereql lEql w tEqJ E osls sr 1I N 'seuJJoJl1uoPoJ A/ o1 OJnl?eJ srql I I Snorqg ?uJel d rn slueurele^ qrns w pl[?l?d poluauo a I [mElsfuc elBed? d rP[ {cql pu? Jel J p pauuoJ $nqpu D $?a[ lE Jo pu? V I eJeuot A\3J I mJ q8noJqt^Fse petn d nolc pe8pe-,tzznJ I

VJ.NOCIONOJ AHJ 8L THE MAJORCONODONT GROUPS

fuzzy-edgedclouds that are irregularly distrib- tends downward to form a distinct anticusp uted through cusp and denticles.Species of a thal bearsseveral denticles on its upper margin t'-..". few early genera(Chirognathus, Curtognathus) and is thus a true anteriorprocess. It seemsun- f,\f' and of at least one Triassic one (Parachirog- necessaryto invent a new morphologicterm nathus)formed elementswith little white mat- for suchan element,which (if needbe) might .//+""-.-) ter and thick lamellaethat are mineralizedby be described as a quadriramate structure with apatite crystalliteswhose prism surfacesare a short,adenticulate posterior process. oriented parallel to the direction of growth. Ancestors of Erraticodon (and thus the Suchelements tend to breakas if they werein- Prioniodinida)are not known, but it is surely ,IDAE ternally fibrous, and Bransonand Mehl used reasonableto rcgardEqaticodon as the plexus this feature to distinguish the order Neu- from which Erismodusevolved in the shallow rodontiformes, Middle Ordovician seas of North America. flDAE It is alsoa characteristicofthe Prioniodinida Speciesof Erismodus (Fig. 5.29) differ from that there is little differencein size or basal thoseof Erualicodonprimarily in that the Pa morphology betweenthe distinctive digyrate componentsof their seximembrateapparatuses elementsassigned to the two P positions,the lack a denticulatedanterior process (but retain ramiform elementsthat occupy M positions, a bosslikeanticusp), and bipennate M elements and those that make up the morphologically lack denticleson the short posterior process conservativesymmetry-transition series. For (and thus have sometimesbeen describedas this reason, diferent authors have assigned "falodontiform"). The oldest speciesof .Eris- comparableelements of variousspecies to dif- modus with which I am acquainted are repre- ferent positionsin the apparatus,with the re- sentedby typically "fibrous" or "neurodon- sult that homologiesare not alwaysobvious. I tiform" elements.However, the skeletalele- will attemptto be unirbrm in the followingdis- ments of later species(e.g., E. quadridaaylus) cussion(and in the classificationin Appendix have more white matter and commonly break A), but my yiews do not alwayscoincide with like othernonfibrous types. This suggeststo me thoseof other authors. that "fibrous" histologymay somehowbe re- latedto the probablyquite unusualcondilions that obtainedin the shallow,very warm Mid- 5.8.1 Family ChirognathidaeBranson and continentwaters in which earlyEru'smodus de- Mehl, 1944 veloped.Later species,such as E. quadridacty- Eqaticodon, the oldest known chirognathid /as, may representforms adaptedto the more and the most ancientmember ofthe Prioniod- normal conditionsthat probablycharacterized inida distinguishedthus far, appearedlate Midcontinenl seas later in the Middle Or- in the Early Ordovician, when it achieveda dovician. Erized in Fig. very wide biogeographic distribulion E. patu The bizarre Chirognathus(Fig. 5.29),repre- Cooper(Fig. 5.29),the oldest(and best-known) sentedin the shallow, tropical waters of the lE:ltuses have species,is distinguishedfrom otherchirognath- Nofth AmericanMidcontinent by a singlespe- rd- or reduced, ids primarily by featuresofthe curiouselemenl cies, is allied morphologicallyto Erismodus, hida are char- I assignto the Pa position.At first glancethat from which it differsprimarily in a skeletalap- blic apparatus element appearsto be pastinate(or "dicho- paratuscomposed of elementswith a scarlike ! and includes gnathiform"), and its associationin the same attachmentsurface skewed to oneface, an alate r digtrate ele- apparatuswith a Pb elementthat is an exten- Saelement without a posteriorprocess, and an Ul slr or seven siform digyrate(or "oulodontiform") element, M elementwith denticulatedanterior and pos- Ilrs tend to be and thus typically prioniodinide, might be terior processes.Cutlognathus (in which I in- lcrgradational taken to suggestthat E. patu straddlesthe cltde Trucherognathus and Polycaulodus) is E chamcteristi- boundarybetween the Prioniodontidaand the alsoa Iikely derivativeof Erismodus,butitsap- rhire matter is Prioniodinida.Closer inspection, however, re- paratus has not yet been competely recon- i- ir elements vealsthat the distinctivePa elementof E. palu structedand, like Chirognathus,it is not likely k ro the axial is also basicallyan extensiformdigyrale ele- to be on the "main line" ofprioniodinide evo- , fr io diffi.rse, ment, but the anterobasalpart of the cuspex- lution. Thesetwo generaare significant,how- 08

|f,! lrr"unuop eql E aqr uI 'uoqec 4J alull dre^ Jo q JrDolur uEunl 'pequcsepuoeq lou sE.q.oaproqqlH Jo ]lua:ulieleed eq.L slueuolo ed pue'qd 'I I'rs 'qs uel ^q a eqr trrJeJ(snpo eql pJeAol po.rolloJ'tqBu eq1le ore sluoEole eSsasnlEredd€ lls ul'(o aprDqqtH'Dutpoluoltd'snPol O) eeprutpor pPQ ro snpolno -ioi1pue(tnqniion4S'mpowsug'uopocrpll3')oepqleuSorqJequoIecrd,{lsorcedsJososnlEreddv'62'5'8!tr lrnFs lEre^es 'JSprurporuoud €uotaq ,{Feelo qtJeddE uI Pol?l PO el?'I Eu€uer t|mqpuSotsrtd Drq ueDr^opro Dsl lEql sercadso I|s ueunlls Er sr lueudola^^[Jeg t()-r.rp ur pes?eJc r'lEl eql ul seuoz F: tlllt\r\ '$IJ?rx I uoos aJe.{\serc Dpro elpprr\l ar€l gorlrpuoc snoJo tttt. 'wtn.b snpolno "nqteu6otlr.lJ^"t.tt^,^ q" rqnoPel I eq pJrlDrtg Puesnp r" ilJeolc sr .tnpo dasJo -rxeseqlJo I'mpolno Jo sal. I uJe ed sql pue aruoJrurporuoud,, a e^vf snporust $urs 'pezl?rcods puas o rcqt tsee trssod ? Jo (€861 qq{o lseequou Duepr^a n aql ur lugurele^ddeJcs lIrE u?Jo peelsuo E! Jelleur elrq.?t\Jo I qloq ur slueulele P rruoJrsuelxo3JE r ? Jo snlElBdde pu? qneluQqrssu q ot f,lleelcsursos slppteqqtH f9 EtJ) snpolno 4td:rllu0l 389 euuoJrluopojn0N mu aqt snql puB ;Jql Surequr 'JaAa THE MAJORCONODONT GROUPS 8l

ever,in beingthe primary "fibrous" conodonts platformedpectiniform elements in P positions and thus the nucleusof Bransonand Mehl's and startedto experimentwith ontogeneticor Neurodontiformes. phylogeneticreduction in the developmentor mineralizationof elementsin various appara- tus positions,the Prioniodinidaremained con- 5.8.2 Family PrioniodinidaeBqssler, 1925 servativeand developmentproduced no star- Oulodus (Fig. 5.29), the oldest prioniodinid, tling modifrcations. seemsclearly to have evolved from Erismodus, Devonian workershave not yet dealt in de- as Schijnlauband I suggestedin 1975.In the tail with the Prioniodinida,but Klapper and apparatrusof O. serralrs, the type species,there Philip (1972)have demonstratedthat the ap- are extensiformdigyrate (or "oulodontiform") paratus of Hibbardella angulata (FiE.5.29), elementsin both positions,only minor patches type-speciesoflllbbardella, differs from that of ofwhite matterin any element,and a dolabrate Oulodus primaily in that the alate Sa element (insteadof an anteriorlydenticulate bipennate) of the former has a denticulateposterior pro- elementin the M position.These features, and cess,whereas that of Ou/odrs hasa stubbypos- scrappy evidencefrom Ordovician rocks in tenor processthat lacksdenticles. For this rea- northeast Oklahoma (Amsden and Sweet, son the assemblyof elementsfrom the upper 1983)ofa possiblyslightly older species. sug- Middle Devonian of Manitoba that Uyeno gest that O. seryatusmay have been somewhat (Norris,Uyeno and McCabe1982) has recently specialized,since all potentialancestors in Er- referredto Oulodusmay representa speciesof ismodus have an extensiform digyrate (or Hibbardella, instead. "prioniodiniform") elementin the Pa position, Murphy and Matti (1982) have established and this patternis repeatedin all youngerspe- the genusErika (Fig.5.30) for a single Early ciesof Oulodus.However this rnay be, the plan Devonian species,which had a seximembrate ofthe sexi-or septimembrateapparatus of Oul- apparatuswith extensiformdigyrate elements odusis clealLyanticipated in thoseoftnJmo- in both P positions,a breviform digyrateele- dus and.Erraticodon. its ancestor.and therecan ment in the M position,and a symmetry-tran- be little doubt about closerelationship. sition seriesthat includesalate. extensiform di- Oulodus qutcHy adaptedto the probably rig- gyrate,and bipennateramiform elements.The orous conditions in shallow subtidal parts of apparatusof Erika divarica, the only species late Middle Ordovician seas,in which its spe- known,is sirnilarin many waysto that ofboth cies were soon establishedas ecologrchall- Oulodus and.Htbbardella; however, the M ele- marks. With enlargementof those marginal ment is not much like that formed by species zonesin the later Ordovician,Oulodus also in- of either genus,and the alateSa elementlacks creasedin diversity, and its evolutionaryde- a posteriorprocess and thus difers from any velopmentis recordedin Late Ordovicianand other prioniodinideconodont with which I am Early Silurian strataby a successionof chron- familiar. ospeciesthat is of considerableutility in Iate Accordingto Nicoll (1980),the apparatusof Ordovician biostratigraphy (Sweet, 1984). Late Devonian specresof Apatognathus (Fig. Pristognathus,represented by a single,short- 5.30)is also prioniodinide, and I include the rangingLate Ordovician species,is closelyre- genuswith the Prioniodinidaein Fig. 5.28.The lated in apparatusarchitecture to Oulodus and elementtypical of Apatognathusin form tax- v clearly belongs with that genus in the onomy was apparentlyan occupantof the M Prioniodinidae. position. SeveralSilurian speciesassigned either to Sparling( l98l) has also concludedthat the (which tratar) and Prion- Oulodusor Delotaxis I includein Ozl apparatusofat leastone Middle Devonianspe- EoEed loward the odus) cany the Prioniodinida through the Si- cies of Prioniodina (P. tortoides) (Fig. 5.29) is lurian into the Devonian but proyide evidence closely comparableto those of Oulodus and of very little changein basic plan or diversifi- Hibbardella in element tlpe and number and cation. In the Early Devonian,when sonleof in morphologicfeatures such as style of den- the dominant ozarkodinidesbegan to develop ticulation. Sparling'sdiscussion suggests that oql tse8itnsot procor peqsllqndeq1 ur enlrt sr pu? (9161) potlo ueeq e^eq '8961 ejeql 'eJeqdnoJ8 srql o1 1r uSrsseI pue '?pIuI 'peorxsid snqnu?DpqruDT^qroN ^q Jo serJeds ruJoJ -poruoud eql Jo lePoru lsJeueaerIT slu sntfiDu8 EuuueseJdeJslueuolE elu?u elqelr"^ElsePlo -opolx luelfuelal4Frur'p4Jn4suocoJ lsnf sv eqt eq ot suees '896I 'peolxeu snlpuSopDlx 'I'ueqtpeuErss" (J861) p?oJxeU qclq^\ ol qorq,rroJ snue8 lueurelelllnu.r pJo sertedstuau suoursod qS aql ueql selr,edssnqpuSopDlx Jo -etuoc luosoJdal lEr{l sdnoJE luarlnceJ ITJJoJ sJsnleJeddeeql ursuonrsod d pardnJJoe^eq ol ourpouoSrT pue 'snporuoudoaN 'o apnqqlH r(lelrt ejour ere D aDpIuSoW Jo selcedsuuoJ 'D aDplruBDI4[ 'snqwuSopDlxJo sercodsuloJ s€ pezruto3eJ,(lsnor^oJd slueruela lDqt lsoE8ns s? pegrluopr ,{Fnoherd stueuolo (@tddlssrs I tnq 'sortods.tn?truSopDtx Jo sasnlz:eddeeq1 -sr] I) ueuelsoqc1?q1 suodel (186I)p?orxau '?purpoIUoud Jo uonJrulsuoJJJsrq ul sluauroled ezIuSoJeJ lou pp (1861)peoJxed snpoluottdoaNJo sarr eql Jo &otsq crozoeled olq eq1 ur elor -edsIIlroJ sE paguuepr Suol ljos eqlJo sluouele lu?lodrul ue p3,(€ld pu? u"ru?^[^suu0d oleJqalop pedeqs-Iord eJe snqwuSopDlx ]]ualc.t r{8noJql u?uetseqC^F?ep ruo+ atu?J trl{datrlElls -elerlFurJoslueurele tN'outpouoSt7 ol pJluournJop? s?q leql ptutpoluouda^tlJull -x?l rrrJoJur pau8rssE,4FeruJoJ sluetuole ^uouo eleu -slp E 'snporuoudolplJo se^n?lueserder suaurelo ES (eepru '€ ^llPe FsrrrelS 'Ic'g '8rd -uedrq .{q uonrsod JS etqlpue :snltouSopEtloT prooar oslE 8'S uoucos uI (,{Iqeqord) pue snryDuSopolx EreueAurroJ eql peJeprsuoceq^lq?qord I[.!\ qcrq,n ^eqJ'eeprqleuSorlceg pezr Jo [mrd,&stuauele etepedonrel ,{q (s,peoJxol{ {prceds gql ol [eJlsaouEselceds prurporuoud @tl? SnUeE rxJoJ lou 'uourdo [lu ur) pelru se^\ uo4rsod qS Jo procar lElele{seqt epnlcur lsourl? 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'esuesluaueleqFur ? uI EsgruErs, ll?rced -er oql ol suo4rppelsuuelod se(1861) p?orxel{ uorlducsep[zr,l.e Durporuoud Jo serJedsJeqlo Ereds 'Uoqs fue^ rruoJrrusr moJJo Ilrew Pve '.(snpotuol.td 1286I) puer(qtuny{ urorJslueuole r{lgJo seqflels stueuele€d puE 'qS ,tq ot po/$olloJ'lq8u uo sluaurolo furpnlcur) slueur 'qd 'I{ 'cS Uol pS(oeplurporuoud) z{ttg puesnqrDuSotDdy ol peu8rsse sorceds Jo lEcrd,{tsosnlaEdal€ puE sluouela '0€'S'3!d rll qloq uI sluelu [f,ullsrp epnlJur 3re u,t\ou)l serc Pls aqlJo slueur Frmu E ur parr g +|JqrPu?'(tI6I) 5 tuslueleulnuj mpotuoLtdorpl [Jguoc dloq ,t?ur $rlr?Jerp osp sr decxa ,r\eJP ds pspnlcur ^luoosle !F 'eroqsJeeuJo ?mua8aqlJo serc tDue elerpeuur ff-m VJNOCONOJ AHJ THE MAJORCONODONT GROUPS

immediate ancestryof Kladognathus, bnt spe- time regardedsuch "enantiognathiform" digy- ciesofthe genusappear to havebeen members rate elementsas occupantsof the Pb position of nearshore,shallow-water associations that in the skeletal apparatus of Ellisonia and,in also included speciesof Cavusgnathus.With thoseofa successionofspecies of multielement only a few exceptions,this ecologicpreference Xaniognathus and.Cypridodella. Hence, occur- is also characteristicof the Prioniodinidaand rence in the Pb position of ttle ldioprioniod.us may help confirm the assignment. apparatusof elements reminiscent of these Idioprioniodus(Fig. 5.31)was diagnosed in a later Paleozoicand Triassic specimenspro- multielement senseby Merrill and Merrill yides strongsupport for the origin of Ellisonia (1974),and their reconstructionhas beencon- and. Xaniognathus in ldiopioniodus or a firmed in a numberof subsequentstudies. Ele- closely related genus.And, becauseI regard mentsof the skeletalapparatus ofthe two spe- Xaniognathusas the most generalizedcompo- cies known are large, mostly hyaline, and nent of the famity Gondolellidaeand E1lr'sozla include distinctive digyrate pectiniform ele- as the centralradical ofthe Ellisoniidae,struc- mentsin both the P positions;dolabrate M ele- turalsimilarity of Pbelements plays an impor- Itio odinidae).Sa Bftom \'lurphyand ments (including the tlpe form speciesof Nea- tant role in my ideasconcerning the origin of prioniodus);and a symmetry-transitionseries thoselineages. offour ramiform elementswith largecusps and very short,sparsely denticulated processes. Es- 5.8.3 Family BactrcgnathidaeLindstrdm, ftiotrs to the re- peciallysignificant in this arrayofskelelal com- 1970 lgn zrlrusspecies ponentsis the diglrate elementthat I assignto In the Treatise Atstin and Rhodes assernbled iendv logical to the Pb position. Lateral processesof this ele- the distinctive Mississippian generaBactro- E relalively rare ment tend to be quite short (althoughthey may gnathus, Doliognathus, Dollymae, Eotaphrus, ler components be longer than those of other elementsof the Scaliognathus, and Staurognathusin a family ristically signifi- Idioprioniodus apparatus),and they project Bactrognathidae.However, they were unable to Eoostruction of downwardlyand anteriorlyso as to form a dis- suggestthe relationshipofthis obviouslyinter- ? i,il. tinct V with the inflated, but undenticulated, relatedstock to any ofthe othergroups ofcon- *ment Klado- baseof the cusp.A closelysimilar type of di- odonts describedin the Treatise. $ occupiedby gyrate element is common in collectionsof In 1985 Kad Chauff demonstrated(to my poslenorpro- Permian and Triassic conodontsand was re- satisfaction,at least)that Bactrognathus,Do- -Vibbardella; the fened by Clark and Ethington (1962) to rhe liognathus,and, Staurogna.thus, the centralele- Ii oplmon, not form genusEnantiognathus. I have for some mentsofthe Bactrognathidae,have skeletal ap- mnrs rypical of r ard (probably) rition by bipen- Fig. 5.31. Elements and apparatuses typical of species assigled to Kladogaathus and ldtopioniodus (pironiodi- pb d m form tax- nidae). Saelements on right, followed ro left by Sb, Sc, M, and P (or and pa) eremenrs. Els df multiele- bped dolabrate led as form spe- d I l98l) did not rEonstructionof Ls species,but I $- recognizedas ; are more likely r the apparatuses the Sb positions d them. *ment Klado- ,of the Prioniod- mp here.There d ro suggestthe qr ilqsqord s?r\ -lels gq 01 eurec sluauele ulJoJlurpeo peuroJ lou eJe,1d.eeprql?u8o4cEg aql Jo slors:eJ8xn U Jqr ur r{lr"g -l?ld eseql'seJnpruls 4"l^3lp ruJoJrsuotxeur nrBr?dd? eq1 ur u€uo rreql elrdsep 't?ql snolmuoJ ,(loJrluo eq srulpu oltoJs-snqlDusonoo5ql sezrJolsa?q; felJ qlr^{ (sJeglo lou,{"ur 1I suonrsod d oqlJo euo uI slueluele lueureleqd eqt Jo uoB"cUpour 3l1eue3ol,4qd EU pUE el?Uued Jo uortecgDorr iq (eE S '?rC) snqtDu8stDqlug rEInurS'dsnJ Jql Jo soptslouelsod PUElou Io Jql SEaleq/rt snounc eql r]I ,{lq?qord pue 'snqlouSonDts -alus eq1qloq uo dole^op sassocordellluuoJ sp E sr sarcods 'mqpuSouo1 ',snqlou3ottzD{ uI esor€ slueur -teld 'p"orq '(snuDtoq)uo 'g pue suD^DJxa 'g) pJeAlno,(llsurlsrp arou rr lusurele l leql -ele peuroJl?ld eqt 'sdnorE luopouoc roferu dnor8auo ur 'pue gronJrdsuoc pu? reqlo uI sv 'sluopouoo Jo dnoj8 Jof?ul srql spueqsarcods Jstunoil uI lueureloqd aqlJo ssec ^q '8rd ur pel"crpul sV rxr ro leurs os SuDIelu uuoJleld l" ldurar" tsJU aql lua$rdeJ -ord l"Jeteluoqs aqr 'Z€ 9 uJ rnq 'pequJsep '.4JlcalJoJrueql peteJfuolur e^eq IJr 'asnec 'sessecordrouetsod puE roueluE aluop?lq q1I^\ I Slrqrqxo oceyns -eq^eql EPrurPoruoud eqlJo uorssncsrp? ur ecu?f,I lueluelo rrrroJrullcedelsuluuec sBpequcsep " :.{[31srpprE,4A \UOttdotpl eldJos -JruErspuoqrpp?Jo arz eeprqleuEorlceg eqa eq tqfiur ernlcru$ oql 'asv'{reqto 'Icols gluoz lueuruloJd E qcns lueseJder leur (snpotuoudolpl Jo -ur se^Jncsse3oJd EuoI eql pu€ pJ?^\lno Dpesoduoc oq ol seneds euos lseel le pue) eepqleuSo4c?g oqJ ,(ltqAqs^[qBIIs spueq ssecoJdleJetel yoqs eql (snlDw 3 tuauqc?lte eql 'slellqeqoJoqs.go purrou eJou pep?Aul'^UJuq -n4 'g) snqtouSottcr8,Jo salf,edsu^rou)[-1s0plo peu^reds o apJDq $ ueql pslqnsrl Jr '^llnJsseccns t?qt ${iols o^eq eqt Jo snleJ?dd? eqt uI'sesnptedde hol eq ol slueur ol r[ees sedolorq esorll Jo suozluep '^ eclposl -qtH pueDulpoluol.rd ur uonlsodelq?Jeduoc e DJ .iJuaPuel oqt -dg 'slueuruorhue relea-^{olpqs ,fte^ uL{[I?cI peuErssuslueurelg ol snoSol?ueosp el? qcrq/i\ peordsepl\l pue uuo;rsuolxo perdnf, rcydotpJ lo selo -qd"r8mEorq lsou 'slueuele s1er,{ttp p c6oql uro{ sals -xel esr9^rp lsorrJ uoeq e^?q ol Ixees^[?crurouo sluopouoc -co eJesnuet qcEaur sercedsJososnlEJ?dd? ^q 3ql ql alEJEdessecue eprurporuoud 'u"rcr^opJo f,lJ?g eqt u! uoll ur suolrsod d rern pu? 'Dutpotuoudpue o ap SuoJ^i sebads sosnl |Eo ilsnol^qo -docur JrernJo eunl eql ruo{ auoDcerlp -nqqtH sprurporuoud eql Jo Jo -sprurporuoud eq1 ur SuDIool uegq o^?q lou lq8ruJ JneqJ -?J?dd?eqt ur osoql 01 rel u$ sI leql ^lasols tsqsllq?lse ur Jr Jepuo^r I 'uorlElerfuelur elq?uos"er 3 eq ,{Bur sauesI J pu€ (S Jo) uoDrsue4-tuleuu^s eql douueue,, eseql slqr oIH,^N 'pJooer u"rddrsslssltrAl u,{\ou)l eql uI sluourelouroJrrrr?J Jo ,{eJ" u? e^eq (Zt S EOJ lerFEe 9A?rI ur potueseJdeJlou sngl $ pu? eJoqs.gorBJ pe^IJ 'Brg,)snqtouSolloe pu? (z€ s Bl.c)snqpuSo'tl r iltuu qs pelceu "F,41 strolotdtl) ot pel?leJ sd"qred stuopo -rr€r qloqJo sartodslsql pe^{oqsJnBqJ 3lBr{8rp Joqlou? -uooJo dnort uI peluur8uo err,eqlq8rur snxeld elmb suleasrepro sql qlr^\ uo4?rcossP^le)IIIlEql " n|sod ?d eql ur oql l?ql pepnlcuoc oq,t\ 'Jn?qJ ,{q pegrluepr seJnlpaleprurpououd os qll.$ sesnleJ"d ^uelu r ue 'suoDrsod I Pr alEuuedrqpu" ,illsJrtoloqdJour 1S861)JnEqJ uorJ u,rerpor ere s$qto :leurauo setn?rJsfilltDuSstoqwg 'elge 5 JO -IXOS E SI -qsrn8ur$rpur oje leqt sluourelo I I pue S e^?q sebads snqtou3ornDs pve s l|tou3olloe '.v^\oul..lJnsn|lou3stoqtug Jo snlereddeololaluro] eeprqlEuBorc€geql Jo eroue8ot peuSrssesercods sosnlapddEpue sluJuola 'Zf'S 'Eld EU'J lSOurF Jo p serJeds 01^Aql Jelr p sJrJeds 'sasnl?J trqJJE uI slSS?UI ds-ad,{t ogl pue lrJ Jo er? u1{oDl f3.rl.{suoed) uu)l E Jo sercodso,{{l uo 1. ,(q peteJfual EseJder tsrg eqJ s n4 ) a uOo t n e ) S. s nq teu 6040 O

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vl-NocoNoJ lHl t8 THE MAJORCONODONT GROUPS 85

liplanate and thus similar in their generalor- tina(FiE 5.33),ktown thus far only from a dis- ganizationto thosedeveloped at varioustimes tinctive Pb elementfrom the I-eonardianHess in unrelatedprioniodontide and ozarkodinide Limestoneof Texas.Later Permiancollections, stocKs. describedin detail by Wardlaw and Collinson (1986)and Croft (1978),include the complete array of elements,which indicatesth^t 5.8.4 Family EllisoniidaeClark, 1972 Swee- lin a had a seximembrateapparatus like that of The first representativesofthe Ellisoniidae,in- Ellisoniabuthad,an elementin the Pb position terpretedby von Bitter and Merrill (1983)as that is reminiscentoflhe triradiateextensiform two speciesof Ellisonia, appearedin the Ato- digyrate element of Ordovician Erraticodon, kan (Pennsylvanian).The youngest species the earliestprioniodinide known. That element known are of Late Triassic(mid-Carnian) age, has one long and one rather short lateral pro- and the type-species(-E lrlaJsicd) is Early cessand a stubby posteriorprocess that bears Triassic.In architectureof their skeletalappa- only one or two denticles. ratuses,species of Ellisonia (Fig. 5.33)are sim- Speciesof Merrillina (Fig. 5.33), another ilar to speciesof ldioprioniodus,from which Permianellisoniid, developed skeletal appara- theyalmost certainly developed. The apparatus ;i

VJNOCONOJ:lHl 98 THE MAJORCONODONT GROUPS

long.profusely denticulated posrerior process; extensiformdigyrate Sb elements;and bipen- nateSc elements, commonly with long,delicate anterior and posteriorprocesses. In the appa- ratusesof generalizedgondolellids, the poste- nor processof Pa elementstends to be short and fragile. whereasthe anterior processis stout and is commonly surroundedat mid- height by a well-developedmidlateral rib. In specializedgondolellids, however, the posterior processof Pa elementsdisappears and the seg- minate structuresthat result may also develop Fig. 5.34. Iareral and undersideviews of a Pa element platform segmentsthat are confined to the of Gladigo ndoI el la (Ellisoniidae). sidesor joined aroundthe posteriorend ofthe cuspto form a continuousbrim. ThaynesFormation of Utah, and one ofthose For many yearsit has been my contention collections also contains a number of plat- that when gondolellid conodonts developed formed pectiniform elementsthat are grada- segminateor segminiplanateelements in the Pa tional in morphologywith the unplatformedPa positionthey alsoceased mineralization ofele- elementsof.E. triassica,and. are also identical ments in other positionsin the apparatus.Ac- in form with the elementson which Huckriede cordingto this view, the Gondolellidaewould (1958) based Polygnathustethydis, the type- include specieswith both unimembrateand speciesof Gladigondolella Mnller (1962) (Fig. seximembrateapparatuses. This interpretation 5.34).Paull (1983)noted the samefeatures in ofgondolellid organizationis basedon my ob- her large Triassic collections and describedthe servation that collections made from rocks Lower Triassicspecimens as representatives of within the range of the Gondolellidaecom- G. meeki. monly conlain either the segminatePa ele- A distinctiye featureof gladigondolellidPa ments or an assortmentof ramiform and pec- elementsis the fact thal narrow platform brims tiniform elementsfrom which it is possibleto completelysurround both anterior and poste- assemblea completeseximembrate apparatus. I rior processes,hence the elementsare formally Only rarely do collectionsinclude a balanced anguliplanate.Comparable elements of the assortment of platformed and ramiform 9 gondolellids, which also occur in Triassic elements. rocks,are segminiplanateand thus are readily For a number of gondolellidspecies, partic- separatedfrom those of Gladigondolella. ularly Triassicones referred to Neospathodus, Platyvillosus, Epigondolella, Mosherella, and Misikella (seeFig. 5.35),I believemy 5.8.5 Family GondolellidaeLin^ftam, 1970 original idea holds. That is, those speciesformed uni- The late Paleozoicand Triassicconodonts as- membrateapparatuses-or at leastonly those sembled by Treatise afihorc in the families elementsin the Pa positionswere mineralized. Gondolellidae and Xaniognathidae form an However,evidence from a coupleofnatural as- Es rhe Sa element obviouslyinterrelated stock that is bestconsid- semblages [one almost certainly coprolitic I ross indicate that ered as a singlefamily. The name Gondolelli- (Rieber,1980)l indicates that othergondolellid dae,coined by Lindstriim in 1970,is the oldest specieswith segminateor segminiplanatePa one available for the combined family. elementsmay have had complete seximem- Gondolellid conodonts formed a basically brate apparatuses.Fot example,Pseudofurnish- lndcles in either seximembrateskeletal apparatus distinguished ias (Fig. 5.35)and at leastsome species of Gar?- primarily by angulatePa elements,breviform dolella (Fig. 5.35) and,Neogondolella (Fig. 5.35) i- E. triassica, is digyrate Pb and M elements (the former "en- appearto have had apparatusescomposed of tkrions I made antiognathiform"), and a slrnmetry-transition segminiplanateelements in Pa positions and Lo*er Triassic series that includes alate Sa elements with a ramiform elementslike those tvoical of Xan- I DporroJeprurpo{ 'suoDrsoos qcrq^l uro{ e€prTlelopuoceql Jo {cols-urels ;p Jrrrouox?l Jo pu? w ur slueureleezrl?Jeuru ol eJnII4 ? Jo e^l]'e^Jesuoc'EurSuet-8uol erll dn epeut o apop arsq pu? ,4n?eJ3 snl€r?dd? erll Jo uolpnpar alelduroc lsorup^q ,{q -udt) pue snqpuSotuoxJo saroedsl?qt puel E{a ?d '1x3u aql raqlreperusdruocc? ueeq e^?q 01surees slueru -uoc I 'peelsul 'old(Ilrsos 1ou,{lJ?olt sr rellErrr I qJnuj eJe ls€al -el3 ?d eleuEldruruSesJo eleururEosJo luaIu eql'D1appuoSoaN ro D appuog Jo serceds I{ pu" .{Eoloqd -dole^ep'sraqlo uI 'uoursod?d eql ur luauolo JO SesnlBJ?ddeeql JO SlueuOdrXOCrrJJOJrrUeJ rI) ale suousod elqntu? e^q"^Jesuoc oJorrr eql roJ luelu i]:.relJ{rere Dlppopttd{J ro srulpuSoluDx tueuJ cdd? pedole^ep -alo (oteu?ldrurur8esro) el?ulruEose Jo uoqnl -ola4lnru ol pouErss?.{lsnor^erd slueurelo [? 4rez o uI 'sontol -Dsqns ,{Iuo pogrpour s"/A snteffdde oql serc leqt (Allumereuop e^eq sJoqln?euos sP)lse8 rDla urJoJrurtted -edspez{€rceds ^q eJoru esoqlJo auros uI eIuBol -tns ol upolulou op I eJuepl,{esrgl 8ur1rJuI 'suorlrsoo FldnJJO SUOrlrS eurl rrro{ pedole^epsluorrJelo ?d ol?uqdrunx s {rJs sr sluopouot -8esJo el?ururSosq1l4r srruoJ pezl"r3eds eJoru pu?WIn(StS e c) o apopttdo ro srull2u8o| *ela{s 3rs€q eqJ

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VJNOCONOJ:IHJ THE MAJORCONODONT GROUPS

Origin of the Gondolellidaeis obscure.Ap- dle Ordovicianage; the youngestare from ear- paratusesof Xaniognathusspecies, the most liest TriassicstEta. generalizedgondolellids, are very close in Except for a few generatransferred from the structure to those characteristicof Ellisonia Prioniodontida,my conceptof the Ozarkodi- species,and it is likely that both stocks ap- nida is essentiallythat of the superfamilyPo- ?s.udolutnishtus peared at about the same time in Atokan lygnathaceair the Treatiseclassification. In (Pennsylvanian)seas. I have already com- Fig. 5.36 (and in Appendix A) I divide the mented on the likelihood that Ellisonia devel- Ozarkodinida into 12 families. Treatise au- oped from the prioniodlnid ldiognathodus, and, thors recognizedonly 6. the gondolellidsmay havehad a similar ances- The cenlral family in the taxonomicscheme try. This suggestionreceiyes some support of Fig. 5.36, the Spathognathodontidae,in- from the fact that PennsylvanianXaniognathus cludesan assortmentof ozarkodinidegenera arld Gondolella characterizea relatiyely deep- that is superficially quite heterogeneous.It waterbiofacies that overlapsone in which ldi- could be made much lessso by includingEog- oprioniodus is also very cornmon. Ellisonia nathoduswith the Polygnarhidae;by erecting and its kin, of course,are especiallycommon separatefamilies for the compactbut distinc- in rocks that represent very shallow-water tive stocks now represenled,by Ancyrodella, by environments. Amydrotaxis ar.d Ancyrodelloid.es,and by Po- My views on relationshipsbetween major lygnathoideq and,by further revision of Bispa- generaof the Gondolellidaeare summarized thodus and,reassrgnment of the resulting parts. diagrammaticallyin Fig. 5.28,and apparatusesIn effect,that lype of raxonomictrimming was characteristicof typical gondolellidspecies are begun in the Treatiseby crealing separatefam- illustratedin Fig.5.35.11 is my suspicion,llies for Kockelella and,Ancoradella and. for however,that formation of segminate(or seg- Pterospathodusand. its kirr. miniplanate) elements in Pa positions (and I have resistedthe temptation to erect the commonly concurTentapparatus reduction) severalnew generaand familiesjust suggested happenedrepeatedly in the history ofthe Gon- on the groundsthat sucha task is bestunder- dolellidae,perhaps as an expressionofiterative takenby someonefar morefamiliar than I with adaptationby successivemembers of the Xan- all the speciesinvolved. On the other hand, I iognathus-Cypridodella stock to similar envi- have not hesitatedto referAlternognathus and. ronmentalconditions. If that werethe pattern, Siphonodella to the famity Elictognathidae,be- the taxonomysummarized in Fig. 5.28is vastly causespecies ofboth arewell setofffrom those oversimplified,ofcourse, although it is difrcult retainedin the Spathognathodontidaeand au- be [n rheapparatuses to imaginea defensiblealternative. thors who havecontributed most to unraveling Sb.5c. M, Pb,and Pa the evolutionary E badmultimembrate history of the two generic L rom thosein the stocksagree that. despite resemblance in some morphologicparticulars, this 5.9 The OzarkodinidaDzik, 1976 stock originated in the Spathognathodontidaeindependently of The basic skeletalapparatus of ozarkodinide the Polygnathidaeand at a much later time in l egminate or seg- conodontsis sexi-to septimembrate,with P po- the Devonian. Those authors may not, how- rcloped from time sitions occupied by carminate and angulate ever, be too happy about my choice of re sp€cializedspe- pectiniform elementsor their platformedana- Elictognathidae. led only by substi- logues.In ozarkodinideconodonts with fully I have also divided the Idiognathodontidae gminiplanate) ele- developedappantuses, elements in S and M of lhe Treatiseclassification into Gnathodon- :!'r-ative angulate positions are commonly generalizedin mor- tidae and Idiognarhodontidae,because such a h orhers, develop- phology and, from published descriptionsat division recognizesa naturaland highly signif- dniplanate Pa ele- least,are much the samefrom one speciesto icant interval in the mid-Carboniferoushistory Ecompanied either the next. Pa elements,on the other hand,r/ary of both groups.The Palmatolepidaeis newly n ofthe apparatus greatlyand haveprovided the principal means establishedfor a phyletic lineagepreviously d€ments in M and of taxonomic differentiation.The oldestozar- submergedin the Polygnathidae,and the Di- kodinideconodonts are from rocksoflate Mid- plognathodus-Sweetognathuslinea$e is re- lFe pnql eql erlJ eprurPou?zo egl Jo {solsl,oor se snlels 'uerddrssrssrt{eql ri ua^aolur euq rreql slgeq s3 'dnoJEaultuEr-euol pus 'cns?ld ur eurrleluossJ^rlEler slr ro snpoqpdstq vtoJJ gi6t) rug4spul'I 'olq"ue^ e aJ?sluopouoc prluopoqteutoqted5 pe^uep i(puepuedopul s" \ qcq,{r 'eeprql?u ll- 'sluelllele d -8olee,ns eprurpo{rezo oql sE Peleerl Feds ? lnq '(u"r 6961'ssoH aDpiuopoqlDuSoqrDds qtwDl I'6'9 puE eepnuopoql?uSlqcuv^lur?J eql uro{ pe^out tlr Jo U?d F ; €r 'PegDuopl^lree IurEddE lelelels 'snor,rqo ore suoqer^orqqB .roqlo :eEplqlEu?oNol I = XVCI,nl :stt{r"u3lqodopflasd = sd '.snpoLlluuSol roJd Jouelsod -ord = u8d :sn|pu8lqdoxs = xs:ou! aultopuod = 'puod epurpolEzo eqlJo eloue8 pue sorllur€J '9€ S 't!tr E{e ES elep u? mrdsuo, 'sluelu FF i(luo sapnlc 2 eqJ. mgnD$ t vo II Nooo HI v N90H.1 v ds E (996I) I pu? I:'X rrro{ sueurr .iq peluesarder $ fvot11tx30x ) ad{l puotesV I '6161 : rr poJJeJsuel '| palu?U e?r(\ SAIC T P:rreJer(996I ) rrnsod polslncll FIP ue Pu? 1ueul 'luauale r u? cs 6 rB4-ftlouru s ? :lvotd:l101vw1vd o Fourb,, ro) alerq ;: ! rr3 'lueureleed I .4o snqpuSouDl pA rrrg) DlduqD fvotHJVN00J2tl:l D6I) I pu? lugrl F.L$ 'euo snleJ 9as qlr^\ sl.uopo =^e o$D '3-1) usDla\eqolI p aseq oql ffeu 9< tdoqreds oql : a{ lvot.n I ErurJurc ur [lJ?e 5 ! o Ersuatxe padole^ U 5 : : sessocoJdrouel r=F a+ F -G x)[ q1l'r slueu.Iele !i B Fod qS eqr ,{dnc F l-- ! rl guq puE 'ssecoJd I 3 4 $nqJ0uSoPqdY DqlEu€oql€dslse d p es elEF aql - tvotHt vNtsnAV3 ',{[e^Dcodser F 1\ €ql ur sluelllele ]VOIHIVN,OJ ] ]MS V qE sspnlsul 1"q1 B IFrnSu4srpunu3 L. t slEJqeloP? :suotl t luurlrad eleln8ue r 'Jldurs ,{[leJrs urJtrrrldSsJo -rxas

YJNOCONOSAHI 06 THE MAJORCONODONT GROUPS 9l

sexi-or septimembrateskeletal apparatus is ba- of early spathognathodontidis representedby sically simple, with bladelike carminate and speciesthat have been included in Aphelogna- angulatepectiniform elementsin both P posi thus and.ln Plectodina.The type-speciesof ! 6 tions;a dolabrateor bipennateM element;and Plectodina,however,has a pastinateand not an an undistinguishedsymmetry-transition series angulateor carminatepectiniform elementin I 6 s that includes alate, diglrate, and bipennate the Pa position and is thus a typical prionio- t elements in the Sa, Sb, and Sc positions, dontide. The type-speciesof Aphelognathus, aftoAE respectively. and all other specesofthe genusexcept Middle The alate Sa elementsof most of the earli- Ordovician A. kimmswickensisand. A. gigas, est spathognathodontids(e.9., "Plectodina," has a pair of typically spathognathodontidP g/l Aphelognathus)lack a well-developedposterior elements.Thus, in this volume I will assign 6/ | process,and breviform digyrateelements oc- species such as Pleclodina tenuis, P. florida, cupy the Sb position.A few, however,have Sa and P. bullhillensis to "Plectodina," for their P elementswith long,profusely denticulated pos- elementsare angulateand carminatepectini- terior processesand at leastone species had de- form elements,not the pastinateand angulale veloped extensiform digyrate Sb elements by structurestypical of Plectodinas. s. Similarly, early in Cincinnatian(I-ate Ordovician) time. Aphelognathus gigas and A. kimmswickensis The Spathognathodontidaeare recorded first will have to be included for now in "Aphelo- near the baseof the Nonh American upper gnathus,"in recognitionof the prioniodontide Mohawkian (i.e., the Rocklandian) by con- structureoftheir Pa elements. odontswith severaldistinctive types of appa- " Plectodina"(Fig. 5.37)evolved from P/ec- ratus. One, typified by the specimensBergs- lodina, it the late Middle Ordovician, an event triim and I (1966)referred to "Bryantodina" documentedin greatdetail in sequentialcollec- abrupta (bat probably referable now to Yaox- tions from the L€xington Limestone of the ianognathusabruprrs), has a simplecarminate Cincinnati Region.Aphelognathus (Fig. 5.31), Pa element,an angulatePb element,a dola- which wasalso common in the late Middle Or- brate(or "cyrtoniodontiform")M element,and dovician,came to be evenmore widespreadin a symmetry-transitionseries with a bipennate marginalparts ofthe lowlatitude seasthat cov- Sc element, an extensiform digyrate Sb ele- ered North America in the Late Ordovician. ment,and an alateSa element with a long,den- The youngesl "Pleclodind" speciesare evi- ticulated posterior process.Bergstriim and I dently the Earty Silurian "P." hassiand "P." ( 1966)referred the ramiform assemblyto a spe- oldhamensis,which have been referred in most cies we named Plectodina? posterocoslatat I studiesto Ozarkndinabut evidently represent transferred it to "Bryantodina" abrupta in "Plectodina," becausetheir skeletal appara- t979. tusesseem to hayeincluded breviform digyrate A secondtype ofearly spathognathodontidis (or "zygognathiform")Sb elements,instead of representedby the LexingtonLimestone spec- the extensiformdigyrate (or "plectospathodon- A'@HfIDAE imens from Kentucky and Ohio that Bergstrtim tiform") Sb elementstypical of Ozarkodina. and I (1966)made the typesof Bryantodina2 The three typesof spathognathodontidcon- stauferi. '[he apparatus of B-? stauferi in- odonts describedthus far from Ordovician cludes only slightly arched, angulatePa ele- rocksdiffer from one anotherin severalpartic- ments,conspicuously arched Pb elements,and ulars and probablyrepresent diferent lines of an alate Sa elementthat lacks a denticulated development.That therewere also other lines = aEalhus;Pgn. Pro- posterior process.Other componentsof years !obrious. the is indicatedby discoverya few agoofdis- skeletalapparatus of B.? stauferi haye yel to be tinctive but as yet undescribedforms with ex- identified. 8.2 stauferi ranges into only the tensiform digyrate Sb elements in early Late early part of the Late Ordovician (Cincinnat- Ordovician rocks in both Kentucky and Okla- batidae Hqss, 1959 ian),but a specieswith morphologicallysimilar homa and by the sporadicoccurrence in late P elements, "Ctmognathus" pseudofissilis of Ordovician strata in Europe of more or less nls are a Yariable, Lindstrdm (1959), may have continued this typical representativesof Ozarkodina (e.g., d.rp. as befits their line into evenyounger parts ofthe Ordovician. Ozarkodinan. sp. of Bergstriim),whose P, M, )zarkodinida. The The third and by far the most common type and Sc elementshave been known for more Pay Jo ueunus 4e$rd ,(lluoJ"d E>IBSEqUr eSrCJe I peuaplr 3 SSOJd JOUaIU€^Fouel ffB eTldoocs ro f.c tU ' 3 e) srqt d Jqt Jo aprsrep t leeuol e ,{dncco Dajod pepuedxa DO-U pe^uep serc Fq uEunlrs ,tll?g Dd pue 'Je^3^ioq lPlt'Dulpuqozo q ol atllu uorc taol sJedel pue 'ssocoJdJoue6od Pedo -p^ep-]Ja^^ e seq oul auuopltDd Jo lerll sear.q^\ 'sserord louoNod e sryel DutpolDzot Jo tuotuele 5ql l€ql oloN I)qB lE eJnlCruls "S 'sluorrjele ed puD 'qd 'I^[ 'JS 'qS ,{q Uel or perrolloJ 'tq8u uo sluoruele €S leepnuopoql€uto[eds) Du! aul.topuoJ rPuedxe l?qt ur8 pueoulpol.tozoswroluelsoprurpoUezolu"uoduraqlJol€crdxlsolcedsJoses$ErealdDpu€slugtuelx'8€'S'8ld {xn 3{rle^oo$ 3 Iecr'(v6€S 8tc) ier l?Jrdfl uI -r,.rdol uorlrsooes oql ur slueurelae13l? snour Jo) oleFEue 'slusurele?d (,,luJoJrluopoqleuE trrre-6?Ip ol -?Ju1 qllr!\ saneds snorgJruoqJe3f,Fea ,ne3e -oqt?ds,,ro) eleullrueJ qlr,r'snt?JEdde l€le ^1or{s 95lr-qx0eJnpruls pu? ueruo^eo JeJeJsJoqln" ,(uetr l 'ssocoJdJou 1a{s elsJqrueurxas9^4e^Jesuos E eAEqeleJls FnoJql .{[ueruud -olsodpoleln rluop ? $lcel sorcodsDulpouozo ueruo^oc pue ueunls ralEl ur sJosseccnsrl9q1 Fg l4uaurdole^ Jo tualllele eS et?I? eql '.{le^qcadser'suoq pu? sruroJeseql ueunFs eqlJo es?q0rl13^oq? lxsl oleurpJoqns -rsod cS pu" 'qS tS eqr ur slueulele(,,luJoJrl EBr?dde PrtuoPo -lapoepuq,,Jo) ol?uuedrq pu€'(,,urJoJrluopoql 'Brg,)outpoqtozg 10 se,{rlelueserdeJul?ueJ rJaqlo ur sesueJoJ -edsopeld,,ro) el?JrGrpuuoJrsuolxe 'elple Jo 'pequcsep r3r:ql qanoqllv seuesuoursu?Jl E pu€ 'sluat'ueleI I olBuuodrq aq ol te,{ e^eq stuourela qS pue ?S osoq,{\ IJo llmq sr qJrq^{ ro elerqelop'sluollIolaqd (..uuoJ[urpo{J3zo,, fiq(ZL6l 'urorls8ragpu? lee/'\S)ap?cep ? ueql Blunf slr le losgo Erp ssecordrorJol 'sluaul0Io roJo slueuIeleed ed puE 'qd 'hI 'cS '.qS,(q Uol ol po^rolloJ'lq8u uo stuotllolo€S'seprurpo1Jezo uErcr^opro orll Jo .4suetcEEqt pue [reJnns) rllsal 'd peeJdsophr Noru oql ,.'oulpopaH,, p.desnqtouSoplldv lo s.oeds Jo I?Jral^l sesnlereddp pue stueuola '/f'9 't!tr horu u slueluele b esotftot DuUIau od eqt pegldrurs ;2 pue Sreqpueg uB-r le pa^lo^ur gmoJ snoJoJruoq eur :og luaruuBrs s Duupultopuod I rprJep ot alqrs FIJO^{ Ueeqo^€q p FJpuBqe .{luo 'ilalEunuoJun lo'.s 'EIc)sr6l Drl'rulsuoc snl?l I Ei\oqs szq (286I t uI) oue.(n qrrq^l Dlllw Dullpuuop

VJNOCONOJ AHJ z6 THE MAJOR CONODONT GROUPS 91

dorinellinaMiller and Miiller, 1957(Fig. 5.38), (Fig.5.398, 5.39C, and 5.39D);in the EarlyDe- which Uyeno (in Norris, Uyeno,and McCabe, vonian of Ozarkodinaseffi (Fig. 5.39G), the 1982)has shownto be closelysimilar in appa- shortliyed speciesfrom which Lane and Or- ratus construction to Mehlina Youngquist, miston (1979)derive both Eognathodus(Fig. 19as(Fig. s.a0). 5.39H) and Polygnathus(Fig. 5.39I) of the Unfortunately,the completeapparatuses of Polygnathidae;and in the late Middle Devo- only a handful of spathognathodontidspecies nian, when Ozarkodinasemialternans (Wirth) havebeen worked out, so it is not alwayspos- spawned" Polygnathus" latilossdtus Wirlh and. sible to decide if Ozarkodina or Mehlina or the Palmatolepidae.Evidently, as Bransonand Pandorinellinais the appropriategeneric as- Meht noted long ago,the notoriouslyunstable signmentfor many Devonian and early Car- basal cavity of spathognathodontidPa €le- boniferous forms or which generic stock is mentsexpanded and migratedtoward the pos- involved at various evolutionary junctures. terior end for the last time in the early Missis- Sandbergand Ziegler (1979) have somewhat sippian.Species produced in that episodeand simplified the problem by restricting Pandoi- their successorsare assembledhere in the fam- nellina Io those spathognathodontidswhose Pa ilies Anchignathodontidae,Sweetognathidae, elementsare morphologicallyclose to thoseof Cavusgnathidae,and Mestognathidae. 'aa :rosl widespread P. inslla (Stautrer),the type-species.Carminate In a secondtype ofdevelopment,sides ofPa l. x- \1. Pb, and Pa Pa elementsofthe latter havea high finlike an- elementsexpanded at or near midlength to terior processthat exhibitsa slightrightlateral form lobulate lappets on one or bolh sides offsetat itsjunctionwith theposterior process. above the central part of the basal cayity. Not Ers, dolabrate or which is built of much shorterdenticles. uncommonly,the upper sidesof theselateral r Eansition series Althoughthere are certainly well-marked dif- extensionsgrew longer phylogeneticallyand I ror "plectospa- ferencesin other elementsof the spathognath- cameto supportone to seyeralnodelike denti- r or "hindeodel- odontid apparatus,dividing the family into cles,commonly arranged in singlerows. Pa ele- I- Sb- ard Sc posi- subordinatetaxonomic groups and tracingde- ments modified in this way characterizeearly t Sa element of velopmental history has been accomplished stagesof Pterospathodus(Fig. 5.39F) in the hnculated poste- primarily throughstudies of Pa elements.This early Silurian; Amydrotaxis and. Ancyrodel- *r Devonian and structureexhibits great plasticity, as I attempt Ioides(Fig. 5.39E, 5.39P,and 5.39Q) in the Fcies with trira- to showdiagammatically in Fig. 5.39. early Devonian; and Ancyrodella(Fig. 5.39K, L position to Par- In typical representativesof Ozarkodinq and 5.39L)much later in the Devonian.Each (Fig. 5.394'),the basalcavity of Pa elementsis oflhesemodifrcation episodes represents a geo- a groovelikeindentation along the lower mar- logicallyshort excursionby spathognathodon- ,as O:arkodinaad gin that expandslaterally to form a cuplike tid ozarkodinidesinto the never-neverland .lL andPa elements. of hasa welld€vel- structure at about midlength of the element platform building in the Pa position.Although -E.: and tapers toward the processextremities. Trealrseaulhors identified the platform-build- From time to time in the long history of the ing excursion that I ed to Ptercspathodusand its Ozarkodina-Mehlina-Pandorinellina plexus, allies as a stock worthy of recognitionat the however,and possiblyalso in the still-obscure family level, the otherswere not so identified Early Silurianhistory of "Plectodina"and spe- and I will not tamperwith this situation. cies derived frorn Aphelognathrrs,the laterally In speciesof Silurian Polygnathoidesand expandedportion of the basalcavity cameto mid-Devonian Torlodus, Pa elements were occupya longerand longersegment of the un- modified in yet a third way. That is, riblike dersideof the posteriorprocess. Elements like thickeningsof the sidesof basicallycarminate this (e.g.,Fig. 5.39.Gand 5.39H)have a ladle- spathognathodontidelements developed into or scooplikeappearance, with the unmodified smooth-surfacedbrim- or shelflikeplatforms anteriorprocess serving as handleand the pos- alonga segmentof the element,commonly the teriorly widenedbasal cavity as scoop.An ex- posterior process(e.g., Totlodus, Figs. 5.39J ercisein basal-cavitymodification like this ap- and 5.41),or around the entire element.The parently precededdevelopment in the early latter type ofdeyelopmentcharacterizes the bi- Silurian of Kockelellaand the Kockelellidae zarreSilurian Palygnathoides (Ftg. 5.40), which qgnoJ e Jo s,{roJlall?Jedqns 'elqnopJo lueudola^ep I?n -grpou lueurale-ed 3o ed,$ '^lleurC 'seqrlr?J -p€€ ur reJrptnq ( D6E 9'AIJ.)*as'O ro (v6€'S A{ou Jo sed^l epPlu Suroq 'eIJ) oiDulput outpo4lDzo leqlre Jo osoql Jo peetsul aeprluopoqlzuEoql?ds aql ur paul?l ol J?lrurs suollsJnEguo3 ,{1l^Ec-l?s?q e/r?q -er ele qloq ecueq:aleqa,{u" o}.,3ull ul€llr,, ffi (It'g puE eql uo ueeq e^eq ol sJeedde sapnqlDu8tlod sarcedseserll Jo slueuele ?d 'O6E S J^ll 'N6€ g 'I 16gS 'sBr{) se^rl?Auep snoJolrrnu )ou snpouoJ JJqlIeu 'soJnlJnrs Jo sod^l sr pue snpolltDdslarJo sor3eds snoleJluoq -cuuslp.qqtq splo uoD?culPour luelllolo-Ed -rpC pu€ ueruo^e(Irelel pus (It'S pu" H6E S 3o adfl srql qSnoqtlv snlH?dde plluopoqleuSo 'sErJ) uEtuo^e(I ,tFPg serJ -ql?ds 'e^nrulud paapur ',{l"uIPJo ,fie^ e^?q snpolltouSog Jo " -edsur sosnl"Jeddeplal3{s sezuelceJ"qtuoqec ot peurrrralep s?q (€86I) uossddal ^llu$er

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VJNOCONOS IIHJ t6 THE MAJORCONODONT GROUPS

denticleson the upper surface.One denticle Pterospalhodus(Fig. 5.39F) and other mem- row, the primary one,extends from one end of bers of the short-lived Pterospathodontidae. the elementto the other.At the anteriorend it The Early Devonian included two closely forms a single-rowed"blade," which is bor- spacedepisodes of innovation in the spathog- dered on either its right or left side by the nathodontid stock. In the first, shortly after the shorter secondaryrow. Numerous modifica- beginning of the Devonian, Pandorinellina tions ofthis basicpattern lead to ozarkodinide (Fig. 5.38)separated from contemporaryOzar- groupsidentified here as the farniliesGnatho- kodina populations (Fig. 5.38) by developing dontidae and Cavusgnathidae. Sa elementswith a denticulatedposterior pro- History of the Spathognathodontidaewas cessand distinctively finned Pa elements.At marked by severalintervals of acceleratedin- about the sametime, iniiation of Amydrotaxis novation that were expressedprimarily in (Fig. 5.40) andAncyrodelloides (Fig. 5.40)was modificationsof Pa elementsalong lines just heraldedby rapid, lobulate expansionof the discussed.In the late Llandovery(Silurian), for centralparts ofbasal cavitiesin Pa elementsin example,migration ofthe expandedpart of the segmentsof widespreadpopulations of Oz4r- basal cavity toward the posterior end initiated kodina remscheidezsrJ.In the secondEarly De- morphologythat cameto be typical of Pa ele- vonian episode,posterior widening ofthe basal ments in the apparatusesof speciesof Kocke- cavity in Pa elementsofsom€what later popu- Iella and,the Kockelellidae(Fig. 5.39B,5.39C, lations ofthe sameOzarkodina stock led to O. and 5.39D).At aboutthe sametime, lateralex- selrt(Fie. 5.39G)then, promptly, to early rep- pansionofthe centralportion ofthe basalcav- resentatives of Eognathodus, with double- ity, eventually to form denticulated platform rowedPa elements(Figs. 5.39H and 5.41),and elements,established the pattern characteristic Polygnathus, with triple-rowed Pa elements of Pa elementsin apparatusesof speciesof (Fig. 5.39I). Although Klapper and Johnson

Fig. 5.40. Elements and appamtuses of sp€ciestypical of genera of the Spathognathodontidae. The complete aFF palatrrses of AmydrcIaxis, Polygnathoides, and Mehlina ate shown, but only the P elements of Ancyrodelloides ite illustrated.The M and S elementsofthe latter are no1known. Rq 4 Fo€trathodontidae ;@r (C), (D) various a6hui (J) Tortodus; )l\atr'cEd B$palho-

lFratuses in spe- Ancy.ode oiclct Gnothodus (Figs. Eronian and Car- frhodus and its r 5.39M, 5.39N, G of thesespecies Iions similar to J inclinata (Fig. )bur difer in grad- tbparallel rows of -uersseI3 ureJJo uousenb eql eq ueql plno^r ueruo^e(Ielrl luelodulr ornJouo4?rllul spJo ereql 'qcusJq..snPogl?dslq,, eql Jo seltedsJoJ -cal (qloq rn ,(lsnoeuerodufetuoaro) oltul Dull pspeou aq p[no,t\ eueu cuaueS raqlouY '.tnp lauHopuod ro luuDulauuDsDulpolttDzo teqllz oqlodsrg ur pouEleJ eq pFoc lL{IuO 'sOrCOdsJo suonslndodur uo$etgrpou lueuele-?d Jo -ed,{l eqt 'snQ$oJrlnurds 8r sepnlcul qcuelq aposrdeJeuqe u?Iuo^eCIelppq I lseleleql uI .,sn1?elncE,,eql esn?cog'seurllueJ3,ulp 7e slllq 'eepqteuEflodeqt',{IlueJ -"r.s 8r uro{ padoleAeP eaeeu\ snpoql0dsry er41 luejeurp ? Jo ruels .w se pue oulpoTrDzo uJo+ Jo seqJuErq.,snloarJo '9,, pve .;npolllDdslq lueurdola^epluopuedJPur ue se snqtouSilod '8r,,eql leql almpur ,{lreolc(tr6l) unsnY pu? '9€'9 trJ ur'pu? a"plluopoql?uSoqteds ^\oqs 'EJoqpues're1fler2 iq pezueuruns serpnls'sr eqr ur (It's 'Eq) snpoqlDuSoguElal I 'uoseel leql ,$e8ms puoqlpp" annbeJ plnot\ .srtpoqt renEl aql nl srulpu8ltlod Jo uoqelp"l Pele snLlPuSIIod Etf zt's'au -rdsrg'eeprluopoqleu8oqledse\l Jo DuUqaI,4{ -qur l"ql euo e\l 'aDauand Pue 01 peuErssesJeJz.i,.r. ',snpoqlodslg Jo sruJoJuels 'uoq?lndodlEllsecu? .{lpesoddts 2rI1 'snlDPS SurauH-Auoloql eq ol peJeplsuoc,!\ou eJ? puB ?Jo esoqluoo/qeq ASoloqfuotrl uI puoqsu8Jt q :ql '(u?unlrs (slueueleeS et?I?snou?rul pue) sluaruelePd sluouele {cel qclq l 'e)ls?lv ruo{ suollcel "d ntr 3q1 PJzi'\oI po^\oJ-olSurse^Eq qary ',ssuaqoln'g pue slllq 1oc Jreqlur spualElu poloddns lou sI luo^e -rl,s'gJr ue^g'[(t86I){crq3s1nc puESreqpues u? qons l?rtrltno lurod^q (616I) uorsruuo pu? ,t ltlltuol 269 :(tl6l) uusnv pue 'tueqpues 'reIezrz ''e'el euv-I 'snporltDuSogJo suowFdod,{llee u.Io{ suodeJa^rleluoron? ur snueSeql uI pepnlsur mqwuS/qod Jo uoll? uep persotilns (St6l) W mpoqrDdstg JJe slueurJlJ Ed pe,rol-JlqnoP pu? -JlE lu6oq1pds eql -urs qloq qlr^\ sorcsdsasn"Jeq 'Je^e,t\oq '0epl1 lrDu.ilodopnasd -uopoql"utoqtEdseql ur (I?'S 'erl) snpo|lDd ll- 'emlnJ 0q1ur -,r/8rsnoJeJruoqrPJ ,{F?g-uauo^eq ul?loJ I rrr:ua8 elanedes 'V xlpuoddv uI Pu? 9€'9 '8ICuI ecrl II pJpnlcurAlou -J?rd lEql ,{lolloJ I pue 'oeprqlEuasn^uJeql Jo Epue'snqrDu&q se^rlelueseJdoJrelel q1l& pedno$ q an snqtou8t :.r2 snqwuSoptl) puz snqlDuSo$od^luourlloJ t iqell dsar srql q uI8 -tllrs 'o?prqlsuSolcllgoql ol?Jedese Jo ! -iq pepunorns su?ds" (V xpueddv uI pu?)"{lIu?J 9t'S 8ICur u^\oqs 9uetuels ?d 01e .Je D apouoqdls pue sn\wuSouD V eauzH tE sJ8?eullqloq 'snoreJruoqJB]lsolueJ Jql ul eJuEuodul ,(Z lou) earqtJo crqdeJErleJlsl?e$ Jo sr tl)rqn.l.'Dapouoqds E pseq e{l-srxp 01 'u?ruo^ecllselq ero ur 'pel 1?q1eeeoull eql € aql Jo suop" pelewur snqlDuSouatlv pluz'eEprl{}"u3oleer\s rec eqt qloq ur pu? eeprluopoqleu9eql Jo Jolsecueeql '(It 9 id rnq 'paqucsop 'a1g) snpoqtDdslgot esu oABB(Of S atd) Dull q4 go snlerzdde -LpW snwouSDptt) pue snqpuSotlDd Jo selo Ipreeai11 ur erurl -edssnouE^ 'retel lrqe'puE(ltS AIu)snqfiu F ur eJuo'$ra11 -SlqdoJSJo sorcads sezrutoceteuo qcrq^\ ) snqtDu8tlodop ,tq suuoJpaaoJ-alqnop ^ll?eaqlJo Jotlaa8ursnJuoc r uro{ {cols eql e or pal (8€'S 'AIJ,)Dul auuopuodJo tuolsq ho-r-eleurs 'e^rl ueluo^o(I el?'I eql ur seEeNI?re.\os 1€ suon"ln dsl€,'ftl?ull -dodur stueruelopdJo suort?cgPou ',(UeuIC ryoqleueoqledS 'oeprluopoqleu8oql?dseql ur btslrlJ0tly 'a^rl osl? 1r spnlcurI 'u?rus"Jceql Jo Pu3 eql l?eu rorrqo slr pu"] enssrlnoqqrn pe4dxe e^eq 01 srEaddP lPql at?a rpJuoJ ,(lpsoJq -ur[ cueueSouour'altuls ? ur popnJcur,(Fpeor p elu 01srraes 1r sr esoreleql lcols eqt osnEceq'pu"(0t S tIC) E (tt'S 'BIc)snp sapolppo.thuv Jo tueurdole^ep ol pel leql ra uo4?nlrs eql euo usruo^e( eq1 sIFJer eposldasrql pdsJ€, JoJtueur ',{llecrSolorldrol^llegl lcors (It'S 'Brl) o apor{ruv

VjNO(IONOJ AH] THE MAJORCONODONT GROUPS

Iorphologicalty, me']tfor Bispathodusand the new genus.Since spathognathodontid species such as Ozarku J Devonian one the situation with Early Deyonian Eognatho- dina abrupta(Aldridge, 1972)began to widen Anatodelbides dus (Fig. 5.41)seems almost preciselyparallel, toward the posterior and also to expand d that aroseis it seemsto me that thebest solution is to assign conspicuously to the sides, giving rise to car- mogeneric lin- broadly conceivedand unrevisedBispathodus miniscaphateelements with a relatively long, :d sithout issue [and its obvious later Carboniferous deriva- even-crestedanterior process and a rathershort I includeit also tive, Rhachistognathus(FE 5.41)1,to the postenorprocess surmounted by small denti- Spathognathodontidae. clesthat declinein sizetoward the processtip. fuenrs in pop- Finally, Bispathodusstabilis, with conserva- Near the end of the Llandovery, continued r l:te Devonian tive, single-rowedPa elements,was apparently modification resultedin Pa elementswith an B 5.i8) led to a the stock from which speciesassigned to Psea- even shorterposterior process and a large,al- >rosed forms by dopolygnathus(Fig. 5.al) developedat leasr mostposterior basal cavity whosebasal margin rirs of Scaphig- twice, oncein the late Devonianand a second hasan almostcircular profile in superiorview Er- vanousspe- time in the early Carboniferous.The complete (Fig. 5.398).Pa elementsofthis sort character- frtathus. Meh- apparatusof Pseudopolygnathashas yet to be ize the apparatus of Kockelella ranuliformis fuvrhodus (Ftg. described,but Pa elementsof primitive species (Walliser),which alsoincludes angulate Pb and lhdonddae and in both the Devonian and Carboniferousiter- bipennate (but neverthelesspick-shaped) M Sulus initiated ations of the genuscombine open, Bispatho- elements and a symmetry-transitionseries !I Devonian,to daslike basalcavities with at leastrudiments composed of bipennate Sc, asymmetrically ln. sratigraphic of three (not 2) denticlerows. Later speciesin alateSb, and symmetricallyalate Sa elements, Carboniferous. both lineagesare distinguished by carminiplan- the latter lacking a denticulated posterior fuionodella are ate Pa elements,with a largebasal pit that is process. Edir \) as parts surroundedby a zone of recessivebasal mar- Subsequentdevelopment of the Kockelella lnarhidae. Sim- gin. In this respect, Pa elementsof Pseudopol- lineageinvolved litlle apparentmodification of fitgnathus arc ygnalhusare homeomorphic with thoseofPo- elementsin the M or S positionsbut substan- f rEpresentatrves Iygnathus, znd,the two heterochronouslineages tial changein those in the Pa position. That frlloe that prac- now includedin the genusv/ill probablymerit changeis markedfirst by developmentofshort sepamtegeneric and familial identity sometime processeson one or both sidesofthe cusp,with -r.{.rtomferous Bls- in the future.At present,it seemsbest to retain no conspicuousmodification in profile of the Fhogllalhodon- Pseudopolynathusand, " Pseudopolygnathus"in basalmargin. The basalcavity of Pa elements rs sirh both sin- the Spathognathodontidaewith the ancestral in samplesfrom slightlyyounger populations is I elemenls are B ispat hodus stabiI is stock. laterally restricledbeneal.h a posleriorprocess Eirarive reports that is somewharlonger than in specimens | ,{usdn (1974); from populations; 5.9.2 Family KockelellidaeKkpper, 1981 older and, in the Pa ele- l[ Evenif 8. stc- ments of the youngest species of Kockelella rrr single-rowed Toward the middle of the Llandoyery (early (Fig. 5.aD, lateral processeslengthen and also lde Sa elements) Silurian),the basalcavity of Pa elementsin a bifurcate,and the basalcavity beneaththem is :ft long-ranging ac reassignedto fuatidae, Bispa- Fig. 5.42. Elementsand the apparatustypical ofa speciesof(ockele/1a, typical genusofthe Kockelellidae. EI surgery.That l4ler, Sandberg, lare that th€ "8. t r" branchesof Eed from .8. s/a- r |le "aculeatus" E4lnJ, the type- -red in Bispatho- rould be needed r- branch.There f familial assign- ',{ueE FrEdde lelele)s 'seuoceqslueuIale d ur ,(luellrulscr8oloqfuour EJ [[nJ ueeq pue'(9L61 'reddEIXpu? Icur"g :Z16I 'llocrN -oluo ur e8els potue^p" ,{lqEqoJd e 1? leql Eifod aqJ pue pEorxad'3'e) ecueuncJo-oouo ?teppeqsl puE-slueuJle Ed ur uoneuuoJ uttJBut ^ral qnd ,{q pouuguoJ lou sl snpaw -l?seqJo sloJluoc eql uI Urqs roulut e u -9!utDf ,69 -DdsotatdJo sluourela^lFoo^rnbeunS pue I I eq ol pesoddns e^Io^ur plnoar ssuaT1aoF DnapDnJuV^Iuo suerurcedspu? slueluols qd puz ed crlsou Jo pcrdih esoql olul slllqDlro^ o aPl)ox 'ti's alcul -a?rp uee,{$equo4ercosse eql 're^eaoH 'selc Jo cllsuepEr"qc slueruola 3d eql Jo uon r mleJ?dd? aql -edsDulpoqozo ,fuHoduatuoc Jo sasntHedd? -"ruJoJsueJleslexeq'DllaplJox IJro+ pe^lo^e (9161) FO"uaoprdqu eql ur seJnFruls olqeJ?durooueql eJolu serrods D apDloruv teql [pelou o^eq red tou pu? eepll snpou.toisreJo sesnt?Jeddeeql uI asoql elqures -d?I)I pu? {olr?g sel slsa8EnsAIuI?lec sluoul t (xIE sr 'sreqto -er (Eb'g 'Arg,)snpolltDdsoDtd Jo senedsu^{ou{ -JlJ Bd ur JsolJ3t.1t lnq 'slsua4zdold 'U ^luelrturs JIJoaJSe 'SnpOlU eerql oql Jo o^\l Jo sesnl?J"dd"oql uI suortrs Jo snl"Jedde eql Jo Ir/t\oDl sI elou tuqloN perdncco (916I redd?DJ 'alEu"ld{lets or? slueruale ?d eseqt 'uoqs I JO Jeqruoru E -od S pu" I I o^"q or ) E) puz snqpuS pus {crueg ,{q tq8noqf slueurole 'eJns 0q oI uI ul3l"ru J?s?qo^rsseceJ Jo auoz peoJq P E[[e JO SuOIlsl 'asrtDatJ eql ur petEJo^p?s? 'f,Iurey eprluopor pepunolns sI qtlq,rr' '1rddsn3qns ? ol peJnp ^q 'xeldruoc [ \ar?unuoJun -uoud u?unlrs lou 'sluopouot opruIpolJ"zo -eJsr Ir^Dc les?qeql 'sJleql eJour " pJeEeJ sr acEyns oql 'JosITl?A\s41g P s13qIIP ueqt Jo lcols ? s€ e?p4uopoqledsoreld eql lueurqcql? lnq Erq s?q sE 'snl I '(2861)utel{ pue I,{q asuesluetuelall -D!to^ ofiap\)ox Jo seuo elEqdecsqlalsaql Jo 'AIC) Ffuodruoc osl? lnru ? ur paqursep^qtunl (Ot'S sapn apo ) esoqt ol JElrurrs.{Jasol3 eJ? Jesrlp,/!\ s, suqJaold stpopquv sel. -uf'Jo sercedsJo osorll pue ns111e16saptor11ou? DnapD.toiuvJo sluauale ed 'eulnno uI qd pue 'olBqdsJsltlels,(UBruoJeJ" l) JJsrtIPA\sauo -oqdtoluD snpoqtodsotaq Jo slueurelo qfuers oql uO stuelllale qcns 'alstl8lp $ 3^oqe I{ 'seprluopoql zd uea^uaq ,{tu?l[urs eql Jo 1nq fI aqt ur snpoql uo{J pea\er^ sz JBIncJIc^llcuqslpreEuol ou q uIEJeu tltutDf ps"q aquo olgoJdeql os 'pepulser requru tE)uet eerqt IIe ll6J zadooJavpuuopotllodsonid € 6'I l?qt hg ueld ur lue lf) snqrDuSopts Al) snqnu8Dl 'oepnuopoqledsoreld eqt Jo ereuoBJo sorJedsJo lecrd,{l sasntEreddEpue slueurolg 'f,t'S '3!d &c6llols eql 'saplo ap =xJads snoue^ d qd oqt pord apsrJeJd tso.up |]q Pedeqs-uoJ uo -{lpJ?^\u^1op (Lr-rleJel?l lnols Etu3[3 el€F8ue . s'npoqndsonld 5e aqt ur uoq I lqr dt pedole^ gJ saplo apo ) ruo stuorrrsls ?d P seprsqloq Jo t q8norql stueur , uo.lJ pedole^ o sueas u 'seprs am lo alElncuue trq sleJrnJrq ro sd etegdBcsrurl eo:d,s snpotltod SFod Pd eqJ !I aql Jo uonBru ) alour B 'e(u JoJ

YJNOCONO" IIHJ 86 THE MAJORCONODONT CROUPS

for me, a more compellingreason for reclassi- earliest speciesknown by carminiplanatePa ficationofthe family. elements,angulate Pb elements,dolabrate (or The Pa position in the apparatusof Pteros- bipennate)M elements,and an S serieswith bi- pathodus speciesvtas occupied by stelli- or pas- pennateSc, extensiform digyrate Sb, and alate tiniscaphatepectiniform elements with simple Sa elements, the latter with a denticulate or bifurcate lateral processesthat may be ad- posterior process. Pa elements formed by enticulateor may beardenticles on oneor both early species of the stem Eenus,Polygnathw sides.It seemsobvious that suchstructures de- (Fig. 5.a4) (e.9.,P. pireneae,P. dehiscens,P. veloped from Ozarkodina-Likecarminate ele- gronbergi), are carminiscaphate; however, in mentsthrough gradual lateral expansion ofone slightlyyounger species (e.g., P. lalicostatus,P. or both sidesat midlength(Fig. 5.39F),just as inversus)the undersideof Pa elementsis plan- Pa elementsof Amydrotaxis (FrE.5.40) andAn- ate, a condition that was attainedby develop- cyrodelloides(Fi!.5.40) arethought to havede- ment of a wide zoneof recessivebasal margin velopedin the Early Devonian. The Pb posi- at progressivelyearlier ontogenetic stages and I tion in the apparatusof the type-speciesof consequentrestriction of the inilially broad Pterospalhoduswas occupied by a distinctive basalcavity to a pit in forms representinglater angulateelement, which bearsat midheight a stagesofeither growthor phylogeny.The pit is stout lateral rib or ridge that projectsout and commonly elongate,situated at elementmid- downwardlyon the outer side to form a chev- length,and enclosedwithin a keellikeridge that ron-shaped lateral lappet. An element of projectsbelow the lower surface,is narrowly almost preciselythe sameconformation occu- groovedon its under edge,extends the com- pied the Pb position in the apparatusesof pletelength of the element,and represents(as various speciesof Early Devoniat Ancyro- doesthe pit it encloses)the under edgeof the delloides. element prior to the stage at which the basal The stelliscaphatePa elementsof Astropen- margin beganto recede. lntidae. tagnathus(Fig. 5.a3),Aulacognathus, and Ap- In Pa elementsof a few species(e.g., Poly- sidognathus(Fig. 5.a3)are only slightly differ- gnathus spicatus) there is no discemible keel in ent in plan from those of Pterospathodus,and, the immediatevicinity of the pit, which is sur- k Cooper,)977 all three genera were included vith Pterospa- roundedinstead by a flat areaof varyingwidth thodus in the Treatise concepl of the Pterospa- that mimics a structuretermed a pseudokeel. riq between Pa thodontidae.However, if elementssuch as the Suchstructures are common to the undersides Hus amorpho- onesWalliser (1964) refened to the form spe- of Pa elementsof Siphonodellaspecies and dspecies of ln- ciesAmbalodus galerus and Pygoduslyra werc may,in mostcases, be usedto distinguishthose fred in a mul- also components of the Apsidognathlrs appara- structuresfrom comparablePa elementsofPo- a Uatti (1982),I tus, as has been suggestedby severalauthors, Iygnathw species. Ea5astockof then all bets are ofl at least for Apsidognathus. Soon after the character of Polygnathus be- r Silurian prion- Unfortunately,I have no other idea about re- came establishedin populationsof Early De- ,.i the Treatise. lations or alternative classification of Apsido- vonian conodonts d escended,from Ozarkodina t$ Barrick and gnathusand corrlinueto showit in Fig. 5.36as selfi l-ane and,Ormiston ( I 979),three main lin- bdVandSpo- a member of the Pterospathodontidae.Car- eageswere founded. Theseare identified in Fig. Iro of the three niodus,as rcconstractedby Bischof(1986)and 5.45 as the linga{ormis, robusticostatus, and ls (Fig. 5.43) re- others,is also assignedto the Fterospathodon-costatusslocks. The natureofthese stocksand = of Distomodus tidae and not to the prioniodontide family their many branchesand the subsequentEarly .!fructures in the Rhipidognathidae as was done in the Zreatise. and Middle Devonian history of their compo- O::nrkodina spe- The apparatusof the type speciesis illustrated nent specieshave been explored in some detail r between diag- in Fig.5.43. by Weddige (1977) and Weddige and Ziegler and specimens (1979),who drew Fig. 5.45and madethe inter- ats of Pterospa- pretationsthat I summarizein 5.9.4 Family PolygnathidaeBassler, 1925 the following ntrrmed by pub- paragraphs. :g.- Rexroad and The few polygnathid ozarkodinides that have The three rnain stocks recognizedwithin Po- per. 1976),and been fully reconstructed have a seximembrate lygnathus by Weddige and, Ziegler are distin- rments becomes, skeletal apparatus characterized in all but the guished in the fossil record by the outline and JOUoISOOAql Ol ?uIl?C eql enu4uoc 01 eires -Iep orlJ 'suollcefloc ur ..luerJoq? J?odde ' ' qc l&\ 'sapou ,(q qlplr,\pur te ua{orq erPslueu 'GL6t) reltev pu" eftppei[ pelou s?", -el} ed uadooJ d Jo ..en8uol, Jouetsodeql 'pu" azrs leoJ8 qceeJ l?ql^q slueuelo uo squ esJa^susrl 'Je,/l.a^roH'\Jols sna-toll8 Ed poluou?uJo ,(lesJ"oc^Iuoururoc 1c?duro3 'lnols a^eq -r{ aqlJosJqJuEJq snous ur sJrJedsJosluau '(LT,st's pue'gz'sv s 'se'sn9 'Ez'9n'9'BIJ) -eI5elq?J"duror olquroseJ snql puB 'pua rouel pu"q raqlo eql uo 'qct{erq smButdpelleJ-os aqt -sod eql le ..en8uol,,pepelJep ,{lpJ?ndu^rop pu" Jo sorcedsluJoJteld eqtJo puo Jouolsodeql te f,lpret"l ? a^"q 'culauul{s? eJe 5lcols ,.en8uol,,paqqu suell 'pedole^eplle\ e srql ur sercedsl?rFecue eql ^Ilqftlseq 01 (6/6I) relS pu? ?uuec pJluec^lesJe oqt;o eprsreqlre uo (sry3no.it -orz pue e8rppeld rqSnoqr 'reddel>I lndoor louuoJpo se u.r'ou)l) sq8nol snqpu8qod Jo sluaulolo^q ?d 'drl roueFod eql deepqllt\ slueuala^fl?cruqcel ?d olEtuole e^?q (tZ S?'S 01 eql ? spuelxeqtrq,{ 'eulr"3 eqlJo aprs puE OZ'S''S'ErC) Iools slqt Jo qcu"rq 'D1ru,{t reqlro^?^i uo pedolo^ep s^\ f,[enbe lnoq" are 1?r]1 -ftq ro 'lertuaa eql dn e{eru leql asoqJ ',fiI srrrroJlelda^?q (lt st'g pue 'LE sv'i '9E sv's -auur^s?lcuusrp Jrer{l pu? 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Er aqr ur pogrluspl r-Erol. 'St'S'3!d

FOnPar euoceq {d '(rt st's pu? aq muol.taFalz I aqt ol spuetxo E pue .,en8uol,, td I"Jutoruu^s fE,lPJdde uadooz t iHRa eqt uI qJo$ sntD$o)u .Jo IsJrd.{t esoql [,e\ ale adooJ E IJ 3ql Jo pue

VJ,NOCONOJ AHJ 001 THE MAJOR CONODONT GROUPS r01

end ofthe element.Thus the Pa elementsofP out beyondthem for slight to considerabtedis- cooperi are transitional in rnorphology between tancesposteriorly. Pa elementsofthe morpho- those typical ofthe linguiformis and Ihe robus- logically conservative robusticostatus brarrch licoslatus stocks. (Fig. 5.45.33),on the other hand, are symmet- In the early Middle Devonian,Polygnathus rical, retain both platform segments,and differ cooperi apparently gave rise to forms with sub- from those of ances1ralP- cooperi only in lack- symmetricalPa elementsthat lack a posterior ing any traceofa posterior"tongue." Symmet- "tongue" and aredistinguished by a carinathat rical Pa elementsof the trigonicus branch (Fig. extendsto the posteriortip. In speciesof the 5.45.16,5.45.18, 5.45.36, and 5.45.37)are zieglerianus branch (Fig. 5.45.1, 5.45.2,5.45.3, blunt, robust,and havewide adcarinaltroughs and 5.45.41),platform segmentsofPa elements that extendfar to the posterior. becomereduced in widlh and the carina iuts Pa elementstypical of the Polygnathuscos-

Fig. 5.45. Lower and Middle Devonian lineages it Polygnathus- Speciesrepresented by the el€ments figured are identified in the text. Modified, with additions,from Weddige(1977) and Weddigeand Ziegler(1979). b lr&i Pelmatolepis

3 linguiformis irnadves (fig. rhich define the r -rongue" that ri[es- whereas ah elementsof d the serotinus l a niJrst icostatus C i.15.1,5.45.2, ftt'1., 5.45.33, bse platforms doped on either t all rhe way to ra- Polvgnathus hddige and Zie- I Secres in this la\-e a laterally Gu.-' at the pos- omparabte ele- rhes of the /in - rsr-erse dbs on antperi Pa ele- !'nodes, which b rhe posterior ueeq ,{FoururoJ a^?q 1"ql srorllo FJe es qu^l Ielelels eql 1noq3atu 01 elqElr"AeuorlsrrrroJur tZ \Stl'.uaddop!'d regle8or '(tt'g 'Art) stdappupd pue '(LV S ou f,lueJJncsr aJeqI'sn)upurutsD srxDrcsam bFl'.oto8u DsoSM '8tg gFo\aaUt OSOpOul ur pe1a1sn11r Ue) sKDpsaW 'DutJaddolx su q3ns a"prdolol.eurledeqt Jo roqurou e uro+ +talqJs otnutw d 'snLlwuSolptuqJs ol pautrss?,{nuaunc sarceds sdeqrodro (S?'S '8ld) r{laorssnJolsu snqpuStl (Z):olarod 1d d -od erll uI rolsecue u^roDlun la,{ s? euos ruo{ z \Ei 'oz) :1ulwrat aau 'aDpgalopwlDd ttllu0f 9 6'9 F d $l):wtaqks uEruoAJCJlpprhl lselel Jql ur pedole^op'sarJ I l8l sDupMw^sD -eds ueluo^eq elrl e ururlsJpJo uorssecJns ..snqtou3/qod,, 'sluopouoJ stulpunoJ e,{q pelueserdar '8lC)snqpuSotl)uv lFrZ'F.L1 pue sulsH Jo '(9t'9 Fqralg 'rt'S '8Id -Jns ro djolsq eJI ar uI seJnl"al luerJnJeJ 'olBp01 poqutsep sluopo ,41[?crposrde01 sluaurale q3ns Jo luaurdolo^ep -uoo rr?Iuo^e(I reddn Jo suoncelloc lsour al"loJ 01 elqrssod oq l(?uj lr pu? 'ejnl ,(qpelueseJdeJ esor0 upql eJoqsol rasoloslueu -celrqcJ?J"lele{s ur ecuecgruArs^Bporuos ruJel-Euol elq? -uolr^ue ul po^Io^ur e Eq KPJIJf,Jols snqpu -rJplsuoJJo sB.r uorupuoJ elEurlsud snour?Jul -&qod ar]l.l?q \ olul lqErsuru" pepr^oJdueaq eql l"ql 'Je^e \oq 'slsetBns edEqs ur ecue8le,r. e^?q o,$teql (586I 'euq puz reddelt) ](ltuec -uoJ pel?lar lou floJns ore qcrq.r -er sr ll pu?'(1961 'sulleH) ll?lep ur 'snqpu8DqDqD)^lesolc,fuo^ pue snqpuSoJoldog sep\ tno ^luopDlro^\ uoeq s"q (dnorE srlolsoJopou^uE snqt -uoporuoud uercr^opJo elpprntr aql Jo stueu -Du8qod e\t) esoqtJo euo ,tluo Jo fueEol,(qd -elo eteu?ldruns?d erll Jo luecsurrroJ osl? aJe eql 'JeAeA{oHsluerxela Bd raqtJo uoo"lueurcIlJo ecqjns Jo slceds? leqlo peqsmtu[srp'sdnoJE lBlueurdole^ap ^eoloqfuourpre^es ^eql uI ragrp pu? Je11q eqt Jo ?uue prourfis pue luasaJdal^q serceds eseql'snoJoJruoqJeJ JglAo'I epou leJluec snonordsuocoql lcq lnq srdalor4 oql luo{ .{luo u,rou)l alE S€ puB :(u?rlu?urq -42J4l snuo8qns eqt ol sJoqlne aruos ,tq paueJ Jo) snoJeJruoqJ?JJe^{o'I eql olur anunuoJ -ar sldappulod Jo sermds (lr?a eqlJo asoql 01 pu? u?Iuo^e(I reddn eql ur J?edd?S :u?ruo^ euqlno (rI reljtl]$ ere snqpuSoJtJuv lo stuesr -eO reddn eql ot pepl4ser ar" SLi(laleurxoJd -ele ed al"u?ldurtsed eql 'trd leseq pereuroc -de'asaqlJo St'S 'ErCuI pelueserder,{u€uBql -aeJqt ,{lleJeue8 'lleurs 1€ le3u ec"Ins Je^\ol Ja8uno{ s{JoJ rrro{ IEual?Iu uo pesBqueoq " eql uo qee{ :a3qrns Jo,i\ol sl.r uo IeaI pedo a,1P'qsnqpu8rQo4 10 sarcadsS I I ueqt eJoI,^{ je^ep1le^\ pu? ec?Jlns reddn s1r uo sepou 'u?ruo^eo elEI aqlJo crl " Jo e^rlru4slp ? sreeq leql eqol prelpl e -suep?#qc Eraue8paleleJ pl.lz snqwu8tlod ^{oJ Jo puE euo Jer\ol eql uo JaeI e pu? ooEyns Joddn se8eeurtotur pedola^epl3ols sntrl eq1uo ?uuEJ ? qlhr srx?JouolsodoJelu? pel\oq -soJeql Jo seroeds^la^rsoldxae^ne^rosuo3 Jo suonpFdod ? Jo lsrsuoc teql seJnlrnJls etEuEId elqzuE^,(HArq 'St'S SrCJodol 0rIl peluoser ^lpratq -Iuns?d eJ?sluer.r.relp zd frq'srulfDuSoJhuv ol -derIe^al eqt a^oqelsnl 'pepulsuoc^q euoceq 01 pauErsw A\ou seroods6 er{lJo ,(u" Jo snleJ?dde pepuelsuuopeld rreqlJo suoqJodrouelup puE J3?t\o!?u OIIIDCOq ICOIS Snlo$n eqt uI SaICedS ueruo,l.o6l epprl Jelel slueruele ?d 'rllEuol '(196t)swlpH r\orl ol op I Jo oJrlue Jrer0 roJ pauJnldn eu"ceq sur8j?ru -otldolttod lo sernBrC1oepql"u3,{tod) otuopotldoltlod puesfiqlDuSortJuv lo ser.odsJostueuole ?d'9t'S'E!d ruJoJlEId s? 'osly 'sa8pu lDtlsot i reproq l€ql setpu agl pu" peurel peruJoJ etuopotldolAlod 'rarursoJ e sr snql eJnleoJo^rlculslp lnq xeldruoJ aqJ euu?c eql ol Ie er?d se8pu u oJ ol esru ol puE puu"J eqt ple^\ol o^JnJ ol slueutes^lol?urrlF pJuJnl -dn osoql uo se8pu esre^suEJleq1 JoJ pu? pJ?.r snqteu6otA?uV -dn uJnl ot srllroJlEld lueurale-?d Jo slueu8es Jouelu? aql Jo sur8Jeru JoJ ,{cuepuel E $"el l? sI eJeql llcols srqlJo seqcusJqII"Jo dJolsrq eql ur Jsl? I ..'pue rouelsod eql l"eu eJncsqoseluoc -eq Jo sJEedd"srp raqlre,, EuueJ eql '(616I) JeJAelZpue a8rppJA\ ot EurpJoJJ?'lnq leJulaur -ru,{s,( ?quesseeJB (St S '8rCJo oprs lqtu eq1 Euop 1 sarcedsa^oqe sauo eql lp) Icols sztrt

VINOCONOJ IIHJ z0r *phodontd l-lrDgnathus and F of Polylophr>

!s DoE assigned lrl5 are pastlm- I of a laterally I e carila on the ! loEer one and trctive row of a a $ell-devel- E keels on the laerally three- Hanate Pa ele- r.lar in outline fulnrulolepis re- abger-us Man- E (rntral node E and differ in Eration. They rtiniplanate ele- ia prioniodon- (,ahabagnathus, {r related. Con- F\er. that the rs of consider- teletal architec- Nlble to relate t ro episodically listory or sur- Fig.5.4?, Elementstypical ofmajor speciesofthe Palmatolepidae.Modified, with additions and omissions,from Helms and Ziegler, in Clark et al. (1981). (l) "Polygnathuf' lalilossalusWirth, (2) "Polygnathus" limitaris, (3) " Polygnathus" cristat s,(4\ Schmidlognalhus wittekindti,(5) Klapperina disparilis;(6) K. dispatalvea,(7) Mesotatis asymmelncusi(E\ Palmalolepistrunsilans, (9') P. p nclata; (10) P. proversa,(ll) P. hassii(12\ P. nicornis,(13) P. subtecla;(14) P. gigas;(15) P. lmguifurmis; (16) P. t ahgulaisi (17) P. pe obataperlobata; (18) P. uepida; (19\ P. 21 termini; (20, 23) P. pe obata schindewolj; (21) P. perlobata moximai (22) P. perlobata helmsi; (24) P. pe obata postera, (25) P. pe obata sigmoideai (26\ P. rugosa ampla; (27\ P. pe obata grossi; (28,29) P. minuta minuta; (30) *midtognathus, P. minulo schleizia;(31) P. grac is gacilis;(32) P. gtucilis gohioclymehiae,(33\ P. grucilis ma ca; (34) P. quadrun- (39) Erated in Fig. tinodosa nllexoidea; (35\ P. quadrantinodosa iaflexa; (36, 31\ P- marginifera; (38\ P. ntgosa tachyteru; P. rugosarugosa: (40) P. quadrantinodosalobata;(4l)P. subpe obata:(42)P. ten ipunctata;(43)P. gtabraprima,(44) 5.14), together P. klappen: (45\ P. glabra acutai (46\ P. glabra lepta; (4'7) P. glabra pectinalat and (48\ P. glabru distorta. mmmonly been

103 lqouoJqc aerql -srpJo Jequnu? ezruSocer(1861 'l? le lrelJ 'selcrlueP !r's '3H ut 6t ur) reIAerZpu? suleH sldappu.qod urllr^|,. lep?orq 'reBuol,(q sle^rolurr?lnter l? raqloue ?stuJurele?d 'relderz euo uro{ pet?$desseprtuep e{qolpeeu 'uoqs ! [er1u$ aqlJo pue surlsH ,{q eurnlo^ asuoatJ 186l etlt JO SlesJo slsrsuocqJrq,{ 'uo[elncrluep r,prol I -EIUU eql SluU JoJpar?doJd rueJS?rp e^rsu9lxe ejolu qcnur E lepoepuq,, e^€q lp sluauele s Jo sessecojd : :epou l?rluoc ulo{ peldep?sr qrlq,n '/t S 8rCur 'ourporuot]dpw 'snpoJlo{ 'olnmJs ol /trnouo r,.itryJr'(i sr lzql -4?urgqcs^IeEr?luaroqs eJ€ sJossocepoJd slr pue^lpc s/d -xe1u.uoJ ur pJll{er ueeqJ^Brl qJlq^r 'slueu b ol at?^o o^Eq -alopnlDd Jo fuoAol,{qdeql ur soJnl?eJrofEtrAl -elecS aleuuedrqpue'qS ele BIp uroJrsuelxa g flql ur serceds 'suorlecrlqndsnolotunu ur sJello^\-oc snor '?Selp1e epnlcur seues uorlrsuerl-frleurur(s aql FoJ snue8qns -r?^ pue Ql6l '2961)reqerz slcor dn oleu teql stuerrJeleJo sed l JnoJJo eoJqt F.$ su6oq leql ueruo?recroddn Jo .{qd"JEneJlsorq^qpaqucsepuo4nloseJ eql 'ssecordJoueluE pepaJrp (lpJe^\u^\op Pd eql Jo lsour -gAIqeqt roJ srseqFdrcuud eqt sepr^oJdpue pue petElmlluep ,{lesnJoJd'8uol p qlr.r esec bo€ uep ue^ ,{le^rsuelulperpnls ueeq seq 'pllo^\ eqlJo supd rell?T aql ur 'soJntcn.IlsuuoJrrrr?J el?uuadrq 'sdapnpuDd ,{upururo{ ur\oDl sr leql sarJqorq? uI paluos aJe' apo|DuqDdpue DutpotuoLtd ^]laedser'D E .iq papnlur -oJdeJ,{lluepunq€ sl qclq^\ 'sldalopwloJ -rls ^leJo seroedss",{uouoxsl ruroJur pegrtuopr 'turoJl?ld : [E4uaJ eqt Jo pedole^ep oqtJo pue rouetup 'sldaloptalod pue srxDrcsall4{Jo stueuale l J lEd a{qe8p ro eqt J?eupel?Jol sr 'opprdeloleuled^Heo,,a eqt Jo lol 'o avouSoqloN snuee |Irc ue {c?l 13ql -secueaqt eq ol posoddnssr qrrq,/i{'( l'rt'S tIC) ruJoJeql Jo saroedsluereJrp 0Z euos ot poJroJ I qllt\ stueujele r4u'tL\,,snpsso!|o| snqpu8t\1d,, Jo sluourele -eJueeq ls?d aql ur e^€q sqt a{rl slueuale qd !J ur Zt sarJeds ?d elpueldrurr.uJ?cJo lrd Fseq otr?l oqt 'pu?q 'seprsqloq Jo auo uo r.uuqJlrlruJoJt?ld Jsop o@uqDd eql raqlo eql uo luauelJ orll Jo uoruod pJrxroJ -ou ,( ?rcgJnsD qlr,r\ sseJordJouelsod ? pue 'epou -leld eql Jo glEueprtlI J?eu pat?nlrs sr leql 'dsnJsnoncrdsuoo 'ss$oJdJouelu? a{qapzlq r:ql uo leda?d lld ps?q el\-DuuaddDlx 'Jutauur^s? 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V.LNOCONOJ lHJ t0r THE MAJORCONODONT GROUPS 105

Erses of species tinct branches,most Out not all) of which are rugosa.P. rugosa ampla (sketch 26) is thought Fina hzve not shown schematicallyin Fig. 5.47.Initial Fras- to be a derivative of the P. (Palmatolepis) ibed nor have nian radiationis representedin Fig. 5.47by Pa stock,which is whereit is placedin Fig. 5.47. nl specieswith elementsofthe groupofspecies numbered 8 to However,Sandberg and Ziegler(1973) postu- E rclationshipof 15.This speciesgroup is identifiedby someau- late development of P. rugosa trachttera d ro the better- thors as the subgenusManlicolepis. Note that (sketch 38) and P. rugosa rzgosa (sketch 39) S Palmatolepis Pa elements of these early speciesof Palmato- from a speciesin the Conditolepis stock that is tarures of their lepishave a prominent lobe on the outer side; relatedto the one u/ith Pa elementslike those a straightor onlyslightly sinuous carina; an un- shown in sketches36 and 37. If the phyloge- r duparilis (Fig. distinguishedcentral node; a downwardlyde- netic arrangementof thesethree subspeciesis JI-6r. and.K. dis- flectedposterior tip; and no parapetalong the as shownin Fig. 5.47(and we may alwayshave dose. and car- inner margin. to guessabout that), some nomenclaturalad- h bladesand a The severalFamennian lineages recognized justmentswill obviouslyhave to be made.The ir of midlength vtithin Palmatoleprs diverge from P. triangu- more important lesson,however, is that gross Each the poste- laris (Fig.5.47.16),whose Pa elementsare re- morphologyofsingle elementsmay not always te under side, latedin rnanymorphologic particulars to those be the best guide to relationship.All of these hel- is a distinct of the Frasnian"manticolepids" but differ in "subspecies"are said to be connectedthrough I$inctly to one havinga moredistinctly sinuous carina: a more morphologically intermediate Pa elements rtasal pit seems conspicuouscentral node; and a platform that with other membersof the lineagesto which fupperina from is flexed upward (instead of downward) they are assignedinFiE 5.4'1. ruhus cristatus posteriorly. Species in the Palmatolepis branch repre- I bsal pit tends SketchesI 7 and 20 to 27 in Fig. 5.47 arePa sentedby sketches28 to 33 in Fig. 5.47 are im morpholog- elementsof a group of species(or subspecies)characterizedby small, narrow Pa elementsin Snatolepis(Fig. that includes lhe type of Palmatolepis, P. per- whichthe smooth-surfacedplatform withdraws ronll have no Iobata.Pa elementsofspecies in this groupare phylogeneticallyfrom the anteriorend and be- largeand conspicuouslysinuous; have narrow comeswidest and best developedposterior of rr5 built by spe- outer laterallobes that generallybear a distinct the centralnode. Anterior of the centralnode, . 5--11.4)have a secondarycarina; and developa low, ridgelike the main axis ofthe elementis developedas a r-like basal pit parapeton the inner sideanterior to the central conspicuousblade. A more important charac- llh of the plat- node. ter of this stock, which was referred to the I On the other The Palmatolepislineage that begins with subgewsDeflectoleprs by Miiller (1956),may rrlin iplanatePa species42 in Fig. 5.47 is distinguishedby Pa be the discovery by van den Boogaardand pc-rarru" Wirth elementswith long, mostly smooth platforms Kuhry (1979)that Pb elementsare not "noth- lrc be the ances- that lack an outer laterallobe but beara serrate ognathellan"but are archedpastinate forms of hrared near the or ridgelikeparapet on the inner side,anterior a type that hasbeen referred in form taxonomy ioped platform. of the centralnode. Species in this lineageare to severalspecies of Tripodellus Sannemann.It rdantly repre- inluded by many authors in the subgenus is difficult to seehow thesestructures can be rl from many Panderolepis. homologizedwith the "nothognathellan"Pb lied intensively van den Boogaardand Kuhry (1979) refer elements of speciesin other Palmatolepis lin- * for the high- most of the Palmatolepisspecies in the stock eages,so it may tum out that this group will '[per Devonian thar beginswith skerch 35 (Fig. 5.47) to the ultimately merit separate generic distinction. P. | 971)and var- subgenusConditolepis. Pa elementsof most When (and i0 that day comes,the venerable E publications. speciesin this grouplack an outer laterallobe, name TripodellusSannemann, 1955 (not De- 4- of Palmatole- haveovate to quadrateplatforms with a carina flectolepis M.ijller, 1956)will be available. losn schemati- that is weakly developed posterior of a large Conventional wisdom has it (e.8., Ziegler ;ed largely from central node; and a sharp-edgedparapet that and Lane, 1987)that Polygnathuslatifossatus m preparedfor rims the inner margin to a point well posterior Wirth (Fig. 5.47.1),progenitor ofthe Palmato- $' Helms and ofthe centralnode. lepidae, developed from speciesof the Polyg- Pa elementsdepicted .in sketches 26, 38, and nathus varcus stock (the far righthand branch I and Zieg.ler(in 39 in Fig. 5.4'7have been taken to represent in Fig. 5.45).Species in that stockbuilt carmi r number of dis- three chronologicsubspecies of Palmatolepis niplanate Pa elements with long, subquadrate |dfs Jo seJnl?eJ e^oJd ol IJo^\ puonrpp? e{et 1I^r 11'elqeqo:d -qcueurou Jourur eruos eJrnboJ(pel"lu?lsqns REsod eql osp aq ot, ollapouotldtg pue 'snpoute 'snqlnuSol JD IIy'r U lnq 'dnor8 eqt Jo lEurelul eql ^rotsq ! JO r(lUElrtIIrS,, -rrlg 'snpulDtr tuorue fur,(uou,{s eql e^aqeq I Jo Sulpue$repun rno etueqc lou IIrA{ eeprluopo F€ds reqlo IIeJo qAnoqtv 'DllapouoqdrsJo seoodsJo snler?dde -ql"utoqpds or{l IIIo+ luaurdole^ep luepuedop qnSuo snpoqDl equo EJ?d eJa/{leqt stueluele roJsnp -uI ue s? o?prdelol?lupd eql Jo uotru8oceu D:DUaITnCCOeql oul( pue sntlpuSopqg^lqeqoJd saur"u JueueS-uJJoJ 'eeprdalot"urlEd aql EuErutoJer ^lrurq ide Jo spunora eqt (6€6I ) rodooJ pue snpoqol eweu e\t pesn roJ srseqpdrcuud sql sr .{tqrqrssodsrqtgo sseu EU Jq 01 e^?q p?q (t€6I) elppnH 'elq,r\uBeII -D apouotld -e^rp?4.le eql l?ql sseJuoc I pue 'uoDaelr qJns rdar lserllPe eql -rSelu?u elnlnsqns oqt posodordIqat{ pu? uos Jeqlou" tueserder ,tEur eEprdeloteurled eql Jo I uE)t! ol ua{81 -ueJg116l ur'ocuoH 'qsg? JoJ pesn lueu.Idole^ed'seun?J luopouoo snoreJruoq$J ^lsnor^erd fs llgJ Dlo4ns uaeqp?q tr esnecaqsluopouoJ roJ posneq lou ,(lJeg pu? 'ueruo^ec 'u?unlrs Jo uoqnlo^e r,ilJe3 qlr?r\ suon plnoc orrr?utEql tnq'(?€6I) IqeW pu? uosu"rg II?Jo o aql ur slua^e luEuodurr s? slsJnq o^n @lnsaotd 011apo I'q snqnuSouotldrs peruEu lsrg se,,l' D apo -aatr qcns pcEer (t86I) sue'I pu? reISerZ pue u luo{ pauodeJ -uoqdts'sr l?ql tl Jo l"crd& lsoru eq ol ue)Fl '(o apotltruv uelrc^ A €!.y-Ipue 'saptolppott) o -sn\lDu8olJrlg snueEeql '(gV'S 3rg.)Dryapouorydrs Jo teql $ s? -rU usruo^eo LIrEg 'snpoqpdsonld ueunls E -!e,!\oq 'pelou 'pet?crldluoosr ,(IIlueJsrqt Jo oJnlepuauroN uI 'E e) olull ur peleJedes,(Iopl,n suollelndod +- 'sauess eql 'lrd eql Jo Jouetu?euo eql u?ql pupsrp JprurpolJEzo ur sluJuralJ Bd Jo sadfl J?lr ,JO SJrJadS TTJJOJ ssol sr lEqt lea)l p"orq ',{ol e ,(q -ulrs luaudole^ep e^rlzJelr,{lsnohqo arlrJ s" ,turouo Jo 'qfuel^lqeJeprsuor slrJo II" ro !?d surosroJ a ooJBurqt Jo s33u?lsur^lesolcJo lere^os paquJsap r(peerp e^eg I al 1?q1slueuele e a^sq .i(€u.Itlxrl 'palopnasd e porrrJol ?elp leql uorlJJuuoJ srql ul pelou Jq oslE 1l EultDuSolJltx ot tEUp?oJq ? perdnccosr trd eqt 01JoFelsod 'pu"q le esolc oJe se^4?uJelP elq"uosEel^EuJ lEaul:lo elsueld uollrsod str lnq^q 'lrd ps?q egl ot Jouelue sJnc Jr .{q uo peu^\o{ @ds euos lseel -co 'e^oort uprpsu e qtlr 'leeI pedola^op{a^1 ,tluoururo3^lJelncrupd----slsrJrlaueSo[^qd eJp spueJl uual-Buol ur slEsre^ej m s€Ar\uoBrsod sselro eroruy 'lrd 1?s?qeql ol rouelsodeceJjns a^Io^ur leql soueueJs lnq 'asrnoc Jo 'elqrssod I ta Sroqpu"s lueuqc?llE aql uo lao{ pougopjle^l {5el lnq -tul lou sr uorluJ^ur:r qJnS'sJrJJdsuuluo^Jc lE " .ltouSoun v lo 'snqpuSqod Jo esoql e{ll 'eleueldrurr.uJecere epprW pu? ,tlJ?g retq II" Jo slueurala ?d eql ) uoqrsoduroJ ol. IIruJ J srql ol peu8rssEser3eds Jo sluerrje[e?d Jo I"rrd& sruJoJtuId Jep?oJq pue strd relpuls fto1,mou1 Kru o1 eql ,(q peo€ldar uoos are^\ faql lnq 'e?prqteE{l r aou l86l'sapouv eqtJo tuolsrq ,{lr?o oql ur peulroJ stueruele soneds 0Z puo ar$nv aoplrltDaSor1q7tltu.tDl] g 6 g -od 4s alelduoc aql €d ur 'osJnocJo'^nueulruoJd poJnEgsJslJ?J?qc r sr aJaql.'sluaur asoqJ serlrluc lEseq efuq fue,r qllt sluaruele Lour eq1 o1 pred 'pal?nl"^a ud peuuoJl"ld luo^urer ot sntossolu € q8noqllv pu" peprulsuocej ueeq aAEquousenb ur sero -r1 d seJrnbeJ{ools ^l,noueu mzn^ 'd eql ar snpssollol " r (lou Jo su.I,{uo -edseqt Jo sesnlH?ddpptrala{s eql lnun pe,{"I d Jo urAuo leql 1no lurod 01 olq?uos?aJun ldord euo lseplo -ep eq IIe,!\ lq8lu lueujuElsseeJleu]roC lueru lou sr lr 'eeprdelot"urpd eql pue sntDssof ^leJns Es [F^{ eEPrqleu -u8rssepruro;ur elecrpu 01 .,snqJou3!qod,,-!pl snqpu8tlod Jo ur3uo aqt uo uo4elnceds nduou,(s rorunf ouqnl eqt pesne^Eq lnq'/t S ro 9g'9 strg ur JeqUnJ as?q 01 qcII/'(\ uo suoltrsslloJ [?3lluc isnqlouSol outq Jo 'eJeqselnoJ f.rEJodu.Iel esoql Jo JoqIa pe,{\ol aq1rou esruedxe eql Jeqlreu e^?q I qEnoqtlv rEJ eql Jo snueA 1oJ lou a^eq I JpEJJpe uEql eJou JoJ(snJ .. poolsJepun lou sr .rn,trs lo 3ql eq -upwtultso l{) requnu reqt Jo euo pepnJcur -soluDl d Jo urglro aql,, l?qt ^Ir?elJtno lurod E pu?) uaq^\^lffelc '1r seq qcq^\ 'smpsal,\[ ar seoedspel?Id . eql lnq ',qrTrqrssodJrleueSol,tqd ? s"^llnJar?c oJuenb e\t pue snqpuSotplurlJs ul popnlcul^p?oJq eq -es e qcns pre8ar oslE (9161) uosuqof pue'Jod 1,r73rutsryossottlol A'esJnorJo'arnsperu fu ?lod -deI>l 're1aarz 'epqq eqt Euol" oreq,{l,tue lueur 'snnssoftlDl u -rrrole sV AJo stu€puecsapeq ol -dole^ep uJoJt?ld lc?l snql pue eteuruu?J sr? pesoddnser" leql $uelllele ?d pet?ld sluourele asoq^L'(t4Ur1,,1) suoutaqotuas (DuIt "d q1l{r seroedsreqlo eql ptre '(f.'LV'| 'Arl)^p?oJq snpl -qaWL=) DurpoltDzo I.lJorJ pe^lo^o -s!r 'd '(Z'Lf S '8rJ) sttD ruI sn Du8tlod ugrs snpssofipl d 1"q1 seDeds eql^llcelp poqsrJq?lse eq -seeJol tuesseoaueq osp plno^rlI ortel,{qd,tlod ueq^i polso38ns're e^\oq '(/96I) qul^\ 'urroJ snue8elq"rouol teql e{?ru pFo^\ os op ol JoJ -lqd pue ep?TqJouorpunf aql Jeeu Jo le pet?n 'snqpuSqod ur tde{ eq re8uolou plnoc sr1trs -lrs seur^eJ IEs?qa8r€l ,tlqessedpue 'sruJoJl?ld -sotrtq snqpuStlod 'sr tEqI lueuusnfp€ [?rnl paprslall"red 'aoJJeu 'uoqs ,{la^uqeJ :sepelq

VINOCONOJ 3HJ 90r THE MAJORCONODONT CROUPS 107

Tgnathuslattfu* b Poh,gnathus, rnerable genus Itassary to reas- $qL 15.17.2), P. uis- hr specieswith bJ& f are supposed ELJ. As a tem- Fig. 5.48. Elements typical of m\ltielement Siphonodella (Elictognathidae). ribiiatus might rlrus and the irii. which has it. When (and if) that happens, Falcodus will and that they might not yet haye appearedin '$l- esymmetri- clearlybe the oldestvalid namefor the typical populationsof S. praesulcatd,the earliestand I have not fol- genus of the family Elictognathtdae, and EIic- least Siphonodellalike speciesof the genus,or y routeshere, or tognathw, Dinodus, ard Siphonodella will be even in early populationsof S. sulcata.Those : rsed the rubric junior synonyms.The family name Elictog- earlyrepresentatives may haveevolved Pa ele- trrmal assign- nathidaewill stand.however. because it is the ments with the essentialcharacters of Siphon- $t well be de- oldestone proposedfor any ofthe genera(syn- odella,bnt they might have retainedthe gen- of the spe- onymsor not) now includedin it. eralizedPb, M, and S-serieselements of their -lesDnsructed and Although a greatdeal of attention has been ancestors.In short, evolution of Siphonodella paid to the morphologyofelictognathid Pa ele- may not have affectedall componentsof the ments,there is no publishedreconstruction of skeletalapparalus equally or at the sametime, the complete skeletal apparatus for any of the and there is no reasonto assumea priori that bsin and 20 speciesnow includedin the family. No one, non-Pa elements were morphologically the 10my knowledge,has ventured even a guessas samein theapparatuses ofevery species. d ro this family to compositionofthe apparatusof any species With the exception of Siphonodellapraesul- td Polygnathus, of Alternognathus(Fig. 5.49.1to 5.49.3),but cata Sandberg,all known Late Devonian rep- r the attachment Sandberget al. (1978)speculated that the Pb resentalivesof the Elictognathidaebelong in l- -\ moreor less position was occupiedin the apparatusof at Alternognathus, which was created by Ziegler dia-n groove, oc- least some speciesof Siphonodella by anguli- and Sandberg(1984) for speciespreviously re- ,.hn its position planateelements ofthe sortcommonly referred fened with question to Polygnathusor in- I b1 a broad flat 1oEliclognathust that the M position included cluded in Scaphignathus,whose species have fr may have a elementsthat havebeen described in form tax- Pa elementsthat are closely similar in mor- I of its lengh, or onomy as Falcodus angulus; and that various phologybut wereprobably derived from Pan- msiderably less form speciesof Dinodus occnpredpositions in dorinellina,not from Mehlina. dthe pit. the S series.As Sandbergand his colleagues The oldestknown speciesof Alternognathus, 7 is complicated, noted, however, no specimensof Dinodus, A. pseudostrigosus(Dreesen and Dusar) (Fig. . 5.48):the genus Elictognathus, or Falcodus angulus have been 5.49.1), formed carrniniplanatePa elements That is, Siphon- reported from rocks with elements of ^trplron- with a narrow,asymmetrically developed plat- bnognathus by odellapraesulcata (Fig. 5.49.a)or from collec- form that bears only a few nodes marginal to :lhat namecould tionswith earlyrepresentatives of ,Srphonodellathe sigmoidally curved carina, and with a nar- rue it had been sulcata(Fig. 5.49.5).These observations were row, flat undersurfacethat has an elongate cE.in 1944Bran- taken to mean either that S. praesulcata and, basalpit but no very distinctkeel. Younger spe- htirute name.$- the earliestrepresentatives of ,S.sulcala would ciesof Altemognathus(Fig. 5.49.2and 5.49.3) ldle (1934) had have to be removed from Siphonodellaon are characterized by Pa elements with more boper(1939) the groundsof apparatusincompatibility, or that elaboratelydeyeloped platforms, which havea thus znd. Dino- the occurrenceof Dinodus, Eliclognathus, and. median carina that is separatedby a slight hblv parts of the Falcodus angulus with the Pa elements typical depression from the anterior blade and rnar- della. Althou$t of alI other speciesof Siphonodella is a rcs,rlr of ginal rows ofnodes or short transverseridges. g,Falcodus, Elic- "similarity of niches." I suggestthat there is Although there is currently a substantial funodella to be also the possibility that the really distinctive stratigraphicgap betweenthe youngestknown d s-ork 1o prove features of Siphonodella developed gradually specimensof Ahernognathusand the oldest blJ;ds u?ruo^ 'snso8ttisopnasdsnqpuSouDtlv uro{ pe^lo^o -plo eqt 'tueqpues otnpsa d D apouotldts 'sesnlelzdde q TuuE oql Jo DtDTnsantd S: l?qt lseB8ns (t86t) Sreqpues DIPP Eq (€os s '3tc) pue J.leerz 'sq8norl leuu?cpe spur fq so8pu -ouoqdrs pu€ snqpuSouJavveql Jo sluauod @lollloq pu? 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S (Lt)'.oppsqo'S (91\:Zl 'uadooTs GI) srpoq touSolotd :piDzlldtupDnbS'(tt):ssEH nsuesrroxrdnp'S (fI)'. 'urlnuarTs (Zl)'.ppqol S ( l)'.fiN'uadooTs (0I):Zt{ 'DtDrudnp (6\ :Dt'l||lutrox (8):lSraqpuDs (L)'.otolldnp (g):btnfls (9):Dtorlnsaotdo apouor|dls (t) uEruuatx?Jlse S S S S S ) :s1Dln3at'V (E):s6uapnq 'V (Z) :snsoButsopfiasdsn|tDuSourarty 0) (8t61) Ilug pu€ 'zrueln"-I 'relSorz'tueqpues .6t.S.3rd d rseploeqJ urol DlapouotldlsJo sorcodsroJ u^\oqs ureled pu? 6I ol t seJnSrdoeprqteuSoplg eqlJo,{uo8ol^qd sjnrPal uo p prtuopoqteut^larll Dle{s slelduroc aepryreu60tctlJ F alIlI'I 'sopou q iq ro sepou D JO qlOOuS eq lEualplur ol rou ld p[luopoqleu8 I trd pelelnouuep E'aleqdmsrulur \{ I snl€J?dde l?le fq pazuapeJ?qJ ue!uoAeo {reds) .tt?qrts ql uI etq Pado uetddtgstsstW Erss€sluopouoJ 6 0.tl!u.ro! t 6 9 o1 x rql Jo pue eql Bds tuspuadepul |xD qll{\ suo4Eln ruollqndod ,tp, u?-\ ur $ueurele Euoz Dtntldnp lt !:lur uE Suraol -S AIl) otorudnp loLrd rqt ,(nuep 61 @4trs S ,(q sno lrms se^\ DlDqns ! 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VJNOCONOJ :IHJ 80r THE MAJORCONODONT GROUPS 109

the simplestand presumablymost generalized that appearedearly in the Mississippian(Fig. memberofthat genus,and not from oneofthe 5.50.5),anterior endsof cup segmentsare di- probablymore specialized,younger species. rectly opposedon oppositesides of the blade. As indicatedin Fig. 5.49,Siphonodella prae- In Pa elementsof two somewhatyounger Mis- sulcata was succeededearly in the Carbonifer- sissippianspecies (Fig. 5.50.6and 5.50.7),how- ous by ,t sulcata(Fi9.5.49.5), which was evi- ever, anterior endsof cup segmentsjoin sides dently the progenitor of highly variable ,S. of the blade at slightly different points. This duplicata(FiE. 5.49.6,5.49.9, and 5.49.13). Fol- conditionheralds one that is commonto the Pa lowing an interval of substantialyariation, the elementsof all speciesof Gnathodus,but it is duplicata zones,features characteristic of Pa combined in Pa elementsof Protognathodus elementsin various segmentsof the S. dupli- praedelicatus(Fig. 5.50.6)and P. cordiformis cala populationsstabilized, and youngerpop- (Fig. 5.50.7)with featuresof surfaceornamen- ulationswith thosecharacters are recognized as tation that are more like the Pa patterns of independentspecies, most of which rangedto older speciesof Protognathodusthan those of the end of the KinderhookianEpoch. somewhatyounger species of Gnathodus. Shortly after Protognathodus praedelicatus (Fig. 5.50.6)appeared in Early Mississippian 5.9.7 Famib Gnathodontidae,new seas,it was joined by geographicallywide- Conodontsassembled here (Fig. 5.36) devel- spreadpopulations of conodontswith similar oped late in the Devonian frorn Bispalhodus but substantially more elaborate Pa elements. rrdbil,1 (Spathognathodontidae).They are Theseconodonts, which representthe first spe- characterizedby a basically seximembrateskel- ciesof Gnathodus,differ from P. praedelicatus, etal apparatusin which Pa elementsare car- their presumedancestor, in a numberof ways. miniscaphate,and Scelements are alate, with a First, Pa elementsare conspicuouslyasymmet- denticulated posterior process.The sides of ric. The anteriorend ofthe cup on the concave gnathodontidPa elementsflare laterally poste- (or "inner") side of the element invariably rior to midlength,and their uppersurfaces rnay joins the btadeat a point well anterior of the be smooth or ornamentedby a few scattered point at which the anterior end of the cup on nodes or by longitudinal or radial rows of the conyex(or "outer") side meetsthe blade. nodes. Little attention has been paid to the Furthermore,nodes on the uppersurface ofthe complete skeletalapparatus, so taxonomy of inner cup segmentcommonly join to form a gnathodontidconodonts is basedalmost en- distinctive ridge- or comblike parapet, vthich tirely on featuresof Pa elements. may be short and weakly definedor long and 'Sionodella from The oldestgnathodontids, from rocksof lat- prominent. In Pa elementsof most speciesof ft | -il -1. rcgularis; (Devonian) t tgt S- duphcata, est Famennian age,are referredto Gnalhodus,the outer cup is more broadly ex- qudruplicata; Protognathodus(Fig. 5.50.2to 5.50.6),whose pandedthan the inner one; it may be essen- 'rc:cha-)S speciesformed carmlniscaphatePa elements tially smooth,may bear inegularly distributed with attachmentsurfaces in broadly expanded nodes,or may have longitudinally,radially, or basal cavities (or "cups") that occupied the concentricallyarranged rows of nodesor low rd the only one posteriorhalfofthe undersurface. Pa elements ridges. i,d€veloped nar- of the three late Devonian speciesof Prolo- In the highly variablepopulations of Gnalr- tat arecarmin- gnathodus difer primarily in the manner in odus that spread with the initial explosive Ital stages but which the uppersurface ofthe posteriorcup is burst, Lane, Sandberg,and Ziegler(1980) rec- r6es. which ex- ornamented;one species(Fig. 5.50.2)formed ognized three rnajor groups. The group that Isrcrior to the Pa elementswith smooth-surfacedcups; Pa ele- centerson G. delicatus(Fig. 5.50.8),and also n of S. praesul- ments of another(Fig. 5.50.4)bear short rows includesG. cuneiformis(Fig. 5.50.1l),is char- I carina that is of nodeson either side of a subcentralcarina; acterized by Pa elements with a long, well-de- ndose marginal and homologouselements of a third species fined parapet. The groups 4pified by G. lypicus Ss- Zieglerand (Fig. 5.50.3)have a node or two on either side (Fig. 5.50.9) and G. punctatus(Fig. 5.50.10) '. S. praesulcata of the carina. In Pa elementsof these Late De- have Pa elenents with short parapets.The lat- lEeudoslrigosus, vonian soecies-and in those of a fourth one ter groups are distinguished by the fact that rIEXrJpr^\ pouephl puE ladend podole^ '0I'09 S eld ur u^\oqs dn.oresnppund 't ^llueuluoJd EIJOJTUn ^IJOIrOJOITI -ep1la^\ 'Euol ? 'sr t"ql :sdnoJEuerddrssrssrtr l oql Jo srequreu lEre^asaql peteJ1snllrIle \ E qSrq E rlll,{\ i(llEa o^u eqt Jo sernleeJpeurquoc t?ql sluour l(lplJedse sr l?ql urell?d e-Jelduns^q eq ol puel lno-r'Jo^e^\oq -elo?d peurroJserceds uerddrssrssrl l lelEl potel trnq 'pezruEoceJeq osl" aex sedtl snpl 'elc) DEB^lJed l{, -aJpuE (t I'09 9 suoaulIq expoqtDugl€ttrt ^eql-Jund pue 'sn)rd& 'snp)tpp eqt Jo stuerrlelo P requerrJpue pezruSoceJ'0S S '3ld ur pozueuuns uoD?leJd ?d'slcoJ uErddrssrssrl^lJelpl l?q/r\euo;ll$ lftbloqtuoul ur -.ra1urcrleuaEol,(qd eql JoJ elqrsuodsel ,{loElEI I ples sr qcrq^\ eJ?oq,{ '(0861)relSelz pue 'tueqpues'oue.I snJrdtt 'g eql Jo slueureleed ur pepu?dxeun ruJsap ,{lluec 'ZI 0S'9pu" 6'09 S '8ld pelHNnllr sr,rr pue eldurs uEruar lrrq'dnote snppund 'D etll 'g E 'dnort aurEs -d& Jo saldruespesotuedns ^q,t[?crqd?JEDHls uI sercadsJo stueurele ?d ur e)lfla8pu ,(lasIe^ Eos ? eq lqarur o^u eql uro{ slueuraleedJo soJnl?eJur luepha -sueJl eruoceqpu? i(flerelsl p?eJdsol puol FoqP tB peJead ,tlr?elcosl? sr tnq '9I'0S'9pue '1.I'0S S '€I.0S.g ?uu?ceqlJo pueJouelsod eql pff.{\ol selcrluep 3 mpoqpug puoqs euot + JoJdnoJE sl?, 'Dqoqluasopltasd O (LI) p:ue:snuDxatC (gltfiorfB-C G:D,svoaulq.D (t l) taqoqvDs t (tI):Zbt,wdQ ? 'la8uo[euroc '9 (ZD :clwtolraunr'g /l.t):sa'pa d (Otl tsDtdlt :stltDruapflpot1tou, .d (L)'.swo) .d t .aC 16) 1f1:stutotrpto| uunauurq I ul -ltapaord'd (9\ luqanq d G) :!plro| (t) '.luosulllor (E) ltauq)eaw siporlDu8ototd (z) :i!i!qo$ snporltod g (t) (086I) rolSorzpue ,tuoqpues,oue-I ,{q peuturr}.p suor1e1e1eepsuoloqieug eqllo fusiolfq4 169.9.a11 I nnauutqaDfi ,xoJo selJnuep 5I) reFerz pu? hofr snj0pund DlssJa^er eJrnb DJOSerseds e fufrmpJJund 6 ,1) DqDptwas pFoqs I 'dno$ 4 llJots snpau E,rpur^ 01 IIIoes w snpoql0u9 'i- aq 01 prss tgJds srq tuo{ Lc86l) ?) eg ! u€rddrssrssrw E {sl e^eq oslE Euauele ed tur I tfr snlDJqapeql 3pI1uopoqlEu8 fue pie snlnau q eraqlJr 'snql I sllJrluop paue frio$ snppund r 1(lasolJ,fia^ sr t\tr,\\'snpauUIq b uErddrssrssu^l F m loaurdole^ rp uoaq e^?q ol lrctu aql ur uoll pqlDu' Jo ser' E$Aqeq suopel !D srq Pu? 3u"'I I Jql ur selJrtuep N y, A/ V]1 ',t,( SN rlJ d

YINOCONOJ AHJ 0l I THE MAJORCONODONT GROUPS lll

denticlesin the posteriorsegment ofthe carina. ,infs presumedprogenitor, be abandonedin Laneand his colleaguesdid not speculateon re- favor of a sirnplerarrangement. I opt at this lations between G. bilineatus and earlier spe- stage for a scenario that requires fewer rever- cies of Gnathodus.However, since simplifica- sals in trend-that is, for a relationship to tJIe tion in the morphologyofPa elementsappears delicatus grotp (and, perhaps, G. bilineatus), to have beenthe hallmark of evolutionaryde- which has a long parapetand posteriorlysim- velopmentin the three major groupsof early ple denticles. Mississippianspecies, it seemsunlikely that G. bilineatus, with its highly complex Pa elements, 5.9.8 Lochrieqand Vogelgnathus is very closelyrelated to either the lypicusot punctatus grcups, even though posteriorly wid- Two additionalMississippian lineages, referred ened denticles are characteristic of the latter. tentativelyto the Spathognathodontidaein Fig. Thus, if thereis a relationshipbelvteen G. bili- 5.36,merit discussionhere, separate from the neatus and any group of early Mississippian Gnathodontidae.One lineageis formedby the gnathodontids,one might be postulatedwith several speciesof Lochriea (also known as the delicatus Eroup,which specializedin build- Paragnathodw)(Fig. 5.51), the other by the ing Pa elementswith long parapetsand might two known speciesof VogelgnathusNotby and also have taken up denticlewidening in mid- Rexroad(Fig. 5.51).Species of both Lochriea Dr:! Mississippiantimes. and Vogelgnathus are represented by bed- Belka (1985) deives Gnathodusbilineatus ding-planeassemblages, hence there are few from his species, G. praebilineatus, which is mysteriesabout skeletalanatomy. There are t said to be "... a perfect horneomorph of substantialquestions, however, about their re- Gnathodus delicatus." Although this would lationshipsto other conodonts. seem to vindicate my "guess" that the G. bili- Lochriea commutatrs (Bransonand Mehl) neatus slock had its origrns in the delicatus hasa seximembrateskelelal apparatusin which group,I shouldalso note that Belkachooses G. the Pa posilionwas occupiedby carminisca- b semiglaber(Fig. 5.50.13),a member of the phateelements that areclosely similar to those punctatusgroup, as the likely ancestor,and not of Protognathodusmeischneri (Fig. 5.50.2)in a speciesofthe /elicatus grcup.This would re- that the cup is smoothon its uppersurface. In- quire reversalof morphologictrends in the G. deed,it would be easyto confusePa elements punclatus group rccognizedby Lane, Sandberg, ofthe two specieswhich, however,differ in re- and Zie{er (1980)by requiring that posterior lative height of carinaand basalcavity and in denticlesofthe carinarevert to simplicity in G. the fact that denticlesof the carina tend to praebilineatus(only I Zegler(1980). (1) to becomecomplex again widen laterallyand developa distinctive can- frti.16) P. pruedeli- in G. bilineatusitself), and that the parapetbe- cellatepattern rn L. commulatus.L. cracovien- @tPifotm$i (12) G. come longer,despite a tendencyin the puncta- sisBelka, the oldestknown speciesof Lochriea, pzdosemtglaber ,rJ group for the parapet to begin short and be- is distinguishedby Pa elementswith cups of come shorter! more elliptical outline and laterallyexpanded, Gnathodusgirtyi (Fig. 5.50.15),which ap- surficiallycancellate denticles on both anterior ht is also clearly pearedat aboutthe sametime as G. bilineatus, blade and posterior carina.Other speciesof Ets fiom the two might be a somewhatsimplified member of the Lochriea,like other speciesof Protognathodus, nples of G. typ- same group. However, Belka (1985) has re- developedPa elementswhose cups are var- 5-50.12. cently describeda new species,G. awtini, iously ornamentedby nodesand ridges. r-d (1980), who are which is said to have Pa elementstransitional Lochriea uacovienJri appears stratigraphi- llilogenetic inter- in morphology betweet lhose of G. texanus,an callyin the biozonejustabove the onein which . 5-50.recognized end memberof thepunctatus Erorrp, and G.gir- Protognathodus cordifurmis is last recorded ;. 5-50.14)and re- /yi. Derivation of G. girtyi from G. austini, andjust belowthe onein whichZ. commutatus is formedPa ele- however,would require that a short parapet, and Gnathodusbilineatus (Fig. 5.50.14)make r of rhe two early with a high anterior node,become longer and their debut.It is easyto postulatea relationship , a long, well-de- more uniform in heiglt; and that the poste- betweenZ. cracoviensisall:d L. commutatus, inendy widened riorly wideneddenticles of G. texanus,G. aus- but difficult to relate either sDecieslo Para- eql 'sorc t-ddE eln ur pepnlc Fffi iro rog u,nou4 4f s^lor 5[cll |[auJle ed prl bort ro a,roorS ffiF,* ) qJnu ssorsE JJo :uo urof 01 I sDu?tsrp8ur {l -trEJur :Euu quap raqlo 0q1 t rql Jo qfuel IJJB ,{eIII pu? I q.rlqa 'apDtq d, e sr 'Duuo) snqrou8pSoAp\re oauqJo1 s.!ced$ l sesnlereddDpue slueuola 'I9'S't!d T ro sePou Jo leeprtuopoqleuSoqleds\ Io Jo leJ.d Fdit seJqrns bsrurur:ec fq ptrcqreuSoIpl '^lr?eJc lueruele elsleue sapnlcu leql snleJ?dd?Fta "S tuo^ lno operu eq touuec sorueBol,{qdl€ql sdet -lols el?Jqrueuues o^eq saDedsu^\ou)[-lsoq " 6411o11 ,(ueruos,{q petentcundsr sdnor8gloqJo,tor oA{l eqJ 'snl"ls cueueSelsJedes lu3ur lou ,{euJ tt!ulD.4 f 6 6 9 -srqeq1luasard ly snxeldpuuopoqleuaorlleds PueDauqxoT ot relllJrs sr '(v xDusddv errns sql uI slooJ 3^?q osl? ,teql esnEcaq pu?) 9€ S '3rg w e?p4uopoqtsuSoqt?ds^Iasolc eql 'poJeprsuocueeq osp e^?q (eDprql?uSoloe,'As)^Eru qlrii\ papnlcur osp '(ls'g ev) snqpuSlaSoA (gl pelElerpu? snpoqpuSoldtlJo sdrqsuo4 'o?puuop lnqDuSot "Jeue8 d:l 'ZS'S'3!d -?ler eqt lDun 'ra^o^\oq'ouop eq lou sql l?ql -oql?uSoqlEds eql Jo ellerqun pop,t\or3 pueruuocoJ I ureql JoJ ? eur?upue tsq,{reluosoql Japunur l! pezeenbse^eq Pu? ^\eu oleoJcol elq"rsep eq ^lrru4 III^{ LI 'o?pnuop 9€'9 'ErCur eep4uoporpeu9eql utorJDauqJoT -oq13u9 puE eep[uopoql?uSoqleds^lq?qojd eql uro+ po^orrJeJ e^eq I 'serpn$ qcns turpuad elEr"dos oaeouqe luessrder snqpuBlaSoA pue 'serPnlserntnJ uro{ uoddns paeu llrna1r lnq Dauq)o1 7ew ele4suouop solpnls amlnJ 'e^rtcerlt" uo4elnceds l"qt puu 'EIC JI _ I 9€ S 'AlrJrqrssoour u.doqs qcols pnuopoqleuBu"rddrssrssrl^l e^rpPll? Uels?e[ le SIl]eeSSrqlDaUqzOTJO uOrS ,{lJee eql Jo uro{ Jo peetsul sllqDls snp -sncsrpSurpeceJd eqlJo /r\er^ur 'Jo^e,r\oH poJe -otltDdslg urorJ^ue KlluepuedePur pedole Lep srswr -prsuoJueeq e Eq ol uees lou seop 'splluop -^nDrr oauqroT trErilsolBlnceds (sg6l) ag ") -oqlEu8Jeqlo ro snpoqput Jo 'seBPUPu? saPou I?l3U 's!llqo$ snpoqpds!8,rrJo{ uort?^ua(I'^uoloou^lluepuedapur -JnsJo uJol.pd xaldruoc ? sl"eq l"ql dnc Jolno q8noJqlpa^erqJe srsoqdlouropeed Jo elduexe lueuruord 3 pu? ledH?d pezuefuolla^\ '3uol uE eq lqfiru sql leql lsa8tns leql'snqpu8p8 E a^"q osl" ,{eql lnq 'selJuueP popu?dxs ,4lP -ol Jo sluoruole?d eJnl?u 0roJo lu$sruruer -relq qlk\ esuu?c a^?q mtDauutq snpoqlDuD are 1eq1 se8els plueudole^ap ,(lJB3 q8noJql JO SlUJUralaEd 'SOJEJ]nSJreql JO Ued UOUrel ssed,snpoqrcug Jo seroeds Jo stueulale -ted puoS^lod snounc E qlr.r solcnueppepuEd 3d aql leqt epu'snqlouSptoA^u"ru roJ slsout"Ip -xe sopnlcul l"ttrl Euu?c e pue ^\3I^ pue ouleu qtoq pepr^ordoqx"(s86J) p?orxeu rouedns^Ilerelelur ols^o ,(lp?oJqer? leql sdncpelueur pue ,{qroN ulsuaJun ar? sdrqsuoq?loJcrleu -"ruoun eAEqsnlrlnuluoJ 7 pue ssuallo)D,tJ -e8ol^qd lreql lnq 's?unJ luopouoc usrddrs 'ZJo sluarllele s"eJeq^r's/rloJ ur poEuerrero "d -srssq l el?l Jo sJoqIIleIIIpu oJdseplr\ zral'dsnql p oll?cs eJ? l?ql sepou ,{q peluaur -ou8p8oA Jo serceds seJelns Joddn rroql uo -eruo flsnoncrdsuoc^I[opu?r pu? e^oqe uro{J pe^\or^ qloous eJEsdn3 pelsnlrs r{Foualsod 'pepu"dxe se pedEqs u?eq eff l?r sdnc culeuu,{s" esoq^{ sluouelo ed olEqdecsrurur-rBc,(IrqEIs e^?q (r'0S S tlg) stuttoltptord Jo pu?^Il?ratq ssecord rouetsod pel?lmnuop '6uol e qll.r sluorrJoloed 'sr 'tzrlJ- 'snpollloug rc snpoqtouS

VJNOCONOJ AHI zlI THE MAJORCONODONT CROUPS ll3 rix processand dose laterally qr are smooth s of Vogelgna- r of late Missis- tlrcir phyloge- il Norby and tottr name and t that the Pa futhodus pass tages that are *ments of Zo- Is might be an tved through tklus stabilis, r other gnatho- : been consid- rceding discus- 5t an attactrYe a rhat Lochriea Leage separate a and Gnatho- riable to create r- I recommend A : until the rela- Fig. 5.52. Upper views ofPa elements typical ofvarious genera ofthe ldiognathodontidae. (A) Declnognathodus; I relaled genera (B) Idiognathoides; (C) Neognathodusi (D) Idiognathodusi and (D Strcptognathodus. E[ considered, ls in the same the his- Fesent 5.9.9 Family ldiognathodontidaeHarris qnd an alateSa elementwith a denticulatedposte- Ed by so many Hollingsworth, 1933 rior process,and is in other respectsclosely : made out yery similar in compositionto that of the presum- Idiognalhodontidconodonts are distinguished ably ancestralGnathodontidae. by carminiscaphatePa elementswhose upper Declinognathodusnoduliferus (Fig. 5.52.\), surfacestlT,icatly bear three longitudinal rows the oldest knowr idiognathodontid,is drstin- Fibodonridae). of nodesor denticles.One of theserows, the guished by carminiscaphatePa elementsin carina, is a posteriorcontinuation of thefree which the carina curves laterally to join the blade, which is assignedan anterior position outer marginal denticle row a short distance and may account for more than half the total posterior of the end of the blade. In Pa ele- length of the element.Conceptually, at least, mentsofspecies of Idiognathoides(Fig. 5.528), the other denticle rows are maryinal to the ca- which appea6 shortly afler Declinognathodus, rina; in fact, the carinacurves laterally at vary- the posterior end of the blade curves abruplly ing distancesposterior to the end of the blade to one sideandjoins the outer maryinaldenti- to join one ofthe marginalrows or is replaced cle rorv wihout forming even a short carina. across much of the platform by a median Furthermore,Pa elem€ntsof some speciesof groove or trough, so that many idiognathodon- Idiognathoides exhibit ClassIII symmetry; that tid Pa elementsappear to have only two den- is, sinistral and dextral specimensdiffer in ticle rows. The complete skeletal apparatus is morphologic detail, but not in overall pattern. known for only a few of the speciesnow in- Early speciesof Neognathodw(Fig. 5.52C) cludedin the Idiognathodontidae.In thosespe- built subsymmetrical Pa elements in which a cies, the apparatus is seximembrate, includes well-developed carina extends nearly to the 'E1g tg Jqf [p?orq Jo dnort lu?lodru srqlJo ,fuolsq pluoudola^ ere g9'9 ur ssqcle{s aqJ- snr*u8Dw pe^\olloJ 'I I qrIIIA 'snpoap -ep eql ul sp^r u"rSoJd ,4j?uounlo^a pue snpJnap J 'snpoqtouSotpl Jo sercads I lJB pue 'suou uB qcns JI snpoqtDuSotpJIo setEeuq snous^ o^u ur sluerxe1eEd Jo lueudolelep crleueEol easq 01 slsedde polceJe srsoqtuoruopeed se uuu? 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'el"cpur ol slueas ocuepr^e crqdeJA suoupleJl"ql pedxe lq8rur euo 'sEun?J 'snxsld,e?po -geJls se 'snpoqrDuSotpJpeu,..eds snpoqpuS -le^rp-A\ol Jo sluouodruoc eJsl,.^sflpotllDuSotp ^trsJ t ruJserder 13ql -otdarts' (u?^\ouow) ueF?^l^suued .{lJ?eJI pue snpoqpuSoial /S'Jo sercedsesnecog '$lcoJ B 9l3OJ qsns ',{urouox?lluopouoc ur rualqordpa,r.losun u"rruJedre^{ol pu? uEru" l^suued luo{ sald | :rtrdsap 'PIJo{r JofeuJ? sluesardalpue snxeldsrq13o turpuzls -ur?sur uoruruoceJ? pogluop! el? qorqa lE ruad reA\o'I -Jepun palecrlduroc ,{leJns s"q srql 'usru"A slueuroleed erp pu?'snoJournu^eql oJe pro I qlsodep 3rlr,{3 1^suuod egl \el.ory snpolliDuSorpl ,{q pot?u ^q-uo8 o,r1 rellEl eql Jo seroedsperrr?N 'uelrrJod F rqnop I suorl -ruop esoql qlp at?uJsll? snpoqlouSofiatlg eql olur u?ru? l,{suued orll qEnorql e8uzr snp iFlurluoc-8uol [q pst"uru]op sl?^JelulcrqdzJ8n?J$ 'sr t"ql -or.lJDuSotplpue snpoqwuSofiatls:tnq'ueru?^ r luo+ suorlJel ,,'u"ru"^l^suuedeql Suunpsaurl l?Jot\essnpo -I,{suuedre^lo-I eq1ol peuguocan snpoqwu8 )umbal IIrA\ lno -qpuSorpl ot ross$cns pue JolsocuEqloq ueeq -oaNpue'saptoqtouSotpl'snpotflouSouq)ao |IIE s$J8ep lue o^eq ot srEedd€snpoqt,uSofiaus ",, t?ql 'se8puJo squ asJe^su"ll I qJrqi{ 'se33e '^llmud,tuc teq \euros petou (L6I 'relsqolA Jo serJes? 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VJNOCONOJ AHJ tu THE MAJOR CONODONT GROUPS ll5 d photographic are of Early Mississippian(Kinderhookian) E tbat represent ageithe youngeslare ofearliest Triassicage. a elongatecup The rootstockofthe Anchignathodontidaeis is ro the poste- formed by a successionof Carboniferous, :en subparallel Permian, and earliestTriassic speciesherein an of course, assigned collectively (and probably quite JStreptognatho- loosely) to Hindeodas. Only a few ofthese spe- rd to that genus cieshave been diagnosed and describedin fully Rl) larger spec- modern, multielement terms, so future work hs'erse ridges may well establishthat severaldifferent lin- d lobaleareas eagesare involved. In line with thepractice in r rt€ platform's many other families, each of those lineages I h.gesl Pa ele- would merit recognitionas a genus,and there ts illustratedby are namesalready available for most of them! l!85). the carina The oldestanchignathodontid known to me, rt of the plat- Hindeoduscrassidmtalus (Branson and Mehl) Eard by trans- (Fig. 5.5a),represents a group of Early Missis- I atrtrolaterally Fig. 5,53. Ontogenetic sequencein Pa elements of sippian(Kinderhookian) species in which car- Idrognathodus- Smallest specimens have morphologic miniscaphatePa elementshave a cup-shaped ndose marginal fea]]'Jfesof Slrcptoghalhodus. D.'aw,n froni photographs hents are the in van den Boogaardand Bless(19E5). basalcavity beneaththeir posteriorhalf and a lnathodus spe- finlike anterior blade that consistsof three or four denticlesthat decline in length and de- mll Straka,and conodonts,I suspectit involved severallin- creasein width posteriorly. These elements lar cryptically, eages,u/hich may have been affected to differ- wereoriginally diagnosed in form taxonomyas tErs to have ent degreesand at diferent times. Sorting this various speciesof Spathodusor Spathognatho- r to ldiognath- out will requirecareful biometric studies ofcol- dus, and it is not possible at present to deter- tmsylvanian." lections from rock sequencesthat represent mine if they representone or dozensof species t dominated by long-continuedstability of depositionalcondi- in a multielementsense. In any event, Pa ele- th those domi- tions. I doubt that it rvill be worked out in the ments of this type are regularlyassociated in fr the Pennsyl- cyclicdeposits by which the Carboniferousand collections from Kinderhookian strata with plicated under- Lower Permianare representedin much ofthe bowedangulate pectiniform elements that have r€s€ntsa maJor world, despitethe fact that collectionsfrom relativelyshort subequal anterior and posterior Eronomy, such rocksare commonlyrich in specimensprocessesand have been identifiedpreviously m*-art) Slrepto- that represent the Strepognathodus-Idiognath- asspecies ofSzbDryanrolrff Branson and Mehl, ndzs. as strati- odzJplexus. 1934. Such elementsqualifu morphologically rdicate, and if and fraternallyas Pb componentsof speciesin z. Slreptognath- the H. crassidentatusgJrou'p. Maybe, after this 5.9.l0 FamilyAnchignathodontidae Clark, group has revised E)- as ontoge- 1972 been and its taxonomy atically in Fig. brought up to date, Subbryantodus will t.urn n and Permian Ozarkodinideconodonts included in this fam- out to be the oldestavailable generic name for rldiognathodus ily have a basicallyseximembrate skeletal ap- rt. caicshifts ofju- paratusthat includescarminiscaphate Pa ele- Cudotaxis piceslingl Chauff, based on ma- ders into adult ments, angulate Pb elements with relatively terial from somewhatyounger, middle Missis- iritial ancestor, shortprocesses, and alateSa elements that lack sippianrocks, also seems to be a memberofthe r€ and more di- any trace of a posterior process.At presentone crassidentatusgroup, and I seeno way to dis- I earlyPermian anchignathodontidspecies is assignedto leti- tinguishit genericallyfrom otherspecies in this f,!' through the ota-,cis,which is peculiar in that its apparatus plexus. Fosis affected appearsto havelacked elements in the P posi- Hindeodus scitulus (Hinde) (Fig. 5.54) rep- drs. If such an tions, and all the othersare included in Ilin- resentsa secondcomponent of the Mississip- ned in the de- deodus, wbich is probably interpreted far too pian species-grouphere referred loosely to trtant group of broadly. The oldest anchignathodontidsknown Hindeodus. H. scitulus has a distinctive car- 'AlC) d puB e^nourl uerddrssrsqtrI alpprrr Jo $[toJ uI lsJU J?od eql sluosordor'sarceds-ed,q oqr '(tS S @a_\i p|Je 'snqr -de dnort sryn$!.tJ snpoaputH etl^tJo seloods (re rr\ pu" tsrnbEunol) sryntsuJ snpoapulH I pJJJoJoJ SerC 'pue plsrp slr lE selcllu0pa{ll 'seloedssnpoapulH raqlo Jo sluelu OJo dnof er{I -elpeeu'EuoIJo relsnlc elelp?r s^IlJullsrp e sdo -JlJ nt qllrr essJagl lou sr qJrq,,A'(uJoJlurpol -la^ep Jaqlo aql s?eraqa'dsnc eql -uoudu,$ ro) aleuuadrq sr tuoluale t l eql pu? 9 Iqlwo! 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VINOOONOJ IIHJ 9I I THE MAJORCONODONT GROUPS 1r7 (Meramecian) age,and the lineageclearly ex- includesancestors of Homoiranognathus,the tends through the remainder of the Carbonif- lesswell-known Permian Rabeignathus and,Ir- erous, the Permian, and into the lowermost anognalhus, and the Early Tiassjc Isarcicella- Triassic.Initially, in 1970,I interpretedPa ele- In the Treatise, Clark and I included all these ments of the youngestspecies krown, H. typi- genera (except Homoiranognathus) with Hin- cdlrj (Sweet),as componentsof the unimem- deodusand, Aethotaxts in the Anchignathodon- brate apparatusof Anchignathodustypicalis, 1idae.However, information published since whereasoccupants of the Pb, M, and S posi- the Treatise manuscript was prepared makes tronswere regarded as components ofthe mul- me uncomfortablewith lhat assignment.Thus, timembrate apparatus of Ellisonia teicherti I now treat Diplognathodusand its kin as an Sweet.Later (Sweet,1973) it becameobvious independentgroup with familial status. The that Anchignathodus typicalis and, Ellisonia family Sweetognathidaewas established(as leicherti werc names for different parts of the Sweetognathinae)for this group by Ritter apparatusofthe samespecies, which ultimately (1986) who, however, included it within the (Sweet,1976; Sweet, in Ziegler,ed,., 1977) was family Anchignathodontidae. shown to be closely similar in skeletalarchitec- In terms of the morphologyof their pa ele- ture to other species of Hindeodus as inter- ments, speciesof Diplognathodus(Fig. 5.55) preted in a multielementsense. Before all of arein many respectshomeomorphic replays of this had beensorted out, however,Cl ark(19'12\ the simpler speciesof Late Devonian-Early had baseda family-groupname onlnchignath- Mississippian Prolognathodus and.mid- to late (superfamily odas Anchignathodontacea),and MississippianLochriea. The pa elementsin this must prevail for the family under consid- question(Fig. 5.55)are carminiscaphatestruc- eration despite the fact that Anchignathodus tures with a cup that expandswidely to the junior has been considereda subjectivesyn- sidesand extendsto the posteriortip. Upper onyrnof Hindeodussince at least 1977! surfaces of the cup are characteristically The skeletal apparatus of Hindeodus cristu- smooth, but rare specimensin a large sample (Youngquist /ff and Miller), the Mississippian may havea nodeor denticleor two. Esoeciallv type-species,is now well known,as are those of distinctive of lhe Pa elementsof Diplignatho- julfensis Late Permian H. (Sweet) and Late dzs, however,is division of the med.iandenti- Permian-Earliest Triassic1L lypicalis (SweeI). cle row into a high anteior free blade and, pos- For the most part, howeyer, Pennsylvanian terior h- and Aethotaxis of it and abovethe cup, a lower carina ts. P elementsof and Permianspecies have beenneglected, and that may consistofa few denticlesbut is more their skeletalapparatuses are largely unknown. typically fused to a smooth idge ot spatula, In fact,a majority ofauthors.whodeal with late which has a subquadrate lateral profile and Paleozoic and early Triassicconodont faunas drops off steeplyto the posterior end of the audus. Pa ele- recognizeonly one speciesin this long interval, cup.Diplognalhoduswas said to have a multi- ,idcztatus grotp H. minutus (Ellison) which, despite substantial membrateapparatus at the time it was estab- tnds in cuplike differencesin morphology of its various skele- lishedby Kozur and Merrill (in Kozur, 1975), le unit and like tal elements,is evenregarded as the seniorsyn- but no illustrationswere provided. It is signifi- rmarion of the onym of FL typicalis, whosetypes are from the cant to note, howeyer, that a hibbardelliform . tte most diag- Lower Triassic.The timited materialavailable (i.e.,alate) element with a long posteriorpro- z of Hindeodus to me suggests,however, that critical analysis cesswas listed as a component. [s ertensiform of larger collectionsthat span greaterstrati- In the same year that Kozur and Merrill te Sb position graphic intervals will result in recognitionof (1975)established Diplognathodus, perlmutter b" One lateral many species.But that is a job for the future. rnterpreted an aggregation of elements that rbe b€ntsharply form a recurrent group in severalsamples from t distance from the 5.9.11 Family SweetognathidqeRitter, 1986 Lower Permian of Kansasas the skeletal mmonly devel- apparatusof D. expansus.Perlmutter's recon- 'oflong, needle- group The of Carboniferous and Permian spe- struction,which includesan alate Sa element cies refened to Diplognathodus, Sweetogna- with a long posteriorprocess, follows the plan q./as group ap- thus, and.Neostreplognathodus nakes up a dis- mentronedvaguely by Kozur and Merrill in e \tississippian tinctive and probably related stock that also their genericdiagnosis. However, perlmutter's J:-r.FJurlsp BpeueCurels"a ur $lroJ uerddrssrssul Jedd0 srqlpazutoceJ osl? 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Jo^llru?J) snlH"dd? eql Jo sluouoduoJ se snsuod I mqlDuSlaqovJo sluarueloBd Jreql ur ssrluBlturrssrtolor{dJor[ -xa 'OJo snla"dde eql ur suorlsodS pue I l eql at (986t ) reuru se pet?leJ se lou ele/,r,.snpoaputH pue Jo sluednccos" palardJalurJe nurFed slueur 1986l)retle{ snpoqtDuSoldt1^IosolJl?ql etecrpur lq8ru sesnl?red -ele urIoJIIrEr aql pr?EoJoq^{ '(986I) IIlrraW ^q q snqtDuSopaLs -de lElalels JreqtJo luauolduror uuoJru?J eql pu€ Jenrg uo^ peuorlsenbueeq Enlo^A drqsuon ur sacueJe.Upl?ql pe$e63nstnq 'uslqoJd e se s"q JeqloEolsluauale ^q aseqldnolS ol uorsbep^llueceJ rypo1 Jo sar3eds r+ osP sea [rel I Jo a*Jrns Jeddn t lueudole^ep 'snpoqtDuSotdal$oaN esoql e)IIl qJnu xTqeqord ore lnq pequcsep uoeq Jo lo .qd .W ,cS ,qS tou e^eq flquuSopa^S pue snpoqtouSoldle Jo slueuole qS Uel 01 sluou.rele?d pue pa,rolloJ dq pausoJ stuoru .gg .3![ 'lq8u uo slueuole eS oeprqleuSoFe^{S eqt Jo aeueS ol pou8rssEsolceds Jo sesnleledds puE stuetllala ^q g aJe.r€q3 v 'sepou .qEd B .4q ,{ll"ret8l 1-ro13onor ayturs Fr areFcrluopeue tnpoqr.utotatlO hJ les?qpepuedxe !d sanunuoJl"ql u e qllf\ slu3luolo d ed eqt ur seJnl FlElncuuep '8uol taqtau'oraaaS ExnalaelE[? qJrq^\ Erx3s 01-rnburnb rlre{I'(SS'S 3t{) rErad ,{lJegeql ur p ulo{ pedole^ep B slsefEns(St6I) !s' pue (sr6l) rel grldicr Jo slueurele IlFEIruns esolJ p a8u?reql uqly( hslls B u.ro{ ele br ol reedd?lEql

VJNOOONOC AHJ 8ll THE MAJORCONODONT GROUPS I l9

that appear to represent Diplogndthodus and are from a stratigraphicinterval that is well within the rangeof Lochriea and.Vogelgnathus. Close sirnilarity in morphology between Pa elementsof Drplognathodusexpansus Perlmut- ter (1975) Sweetognathusmerrilli Kozur (1975) suggests^nd. that the Sweetognathusslock developedfrom diplognathodontanancestors in the Early Permian. Speciesof Sweetognathus (Fig. 5.55),like thoseof Diplognathodus,had,a quinqui- to seximembrateskeletal apparatus in Babeignethus which alateelements in the Sa position havea long, denticulatedposterior process and struc- tures in the Pa position are carminiscaphate elementswith a relativelyshort anterior blade Fig. 5.56. Pa elementstypical of speciesassigned to that continuesposteriorly acrossthe broadly Rabeighat hus and I sarc icel la (Sw eetognathidae). expandedbasal cup as a carinathat is basically an adenticulate ridge, but may be replacedby a singlerow oflow broadnodes or supplemented yet completelyconvinced that this pattern(or laterallyby a pair of subparallelrows of such that of Pa elernents of Rabeignathus) merrts nodes. A characteristic feature of the Pa ele- recognitionat the genericlevel. l&menrs on right, ig',trrs have not ments formed by speciesof Sweetognathusis Sweetognathuswlritei (Rhodes, 1963) was development of a pustulosepattern on the also the apparentancestor, in the Early Perm- upper surfaceof posteriornodes. Such a pat- tan, of NeostreptoqnathodusClark (1972) (Fig- tern was also developedon Pa elementsby 5.55), a stock of stratigraphicallyimportant speciesof Lochriea, which may suggesta rela- sweetognathidspecies with Pa elementschar- ln diferencesin tionship. Evolutionary development of the aclerizedby subparallelrows of nodes sepa- ItEir skeletal ap- Sweetognathuslineage has recently been traced rated by a well-marked median groove or chan- I Diplognathodus by Ritter(1986). nel. It is also of interestto note that nodesin fueb-' related as Ritter (1986)has demonstratedthat species the posterior rows of Pa elementsof Neostrep- Hr Pa elements ol RabeignathusKozur (1978)(Fig. 5.56)have tognathodusspecies seem not to have the dis- a quinqui- to seximembrateskeletal apparatus, tinctively pustulosesurface that is characteris- Mus expansus, similar to that of Sweetognathus.The Iwo tic of comparablenodes in the Pa elements r(1975),is taken known speciesofRabeignathus are recognized, formed by speciesof Sweetognathus,Homoir- Es of otherspe- however, by their distinctive Pa elements, anognathus,Rabeignathus, and Lochriea- T||re rs profitableto which are like the double-rowedcarminisca- significance of these features is diftcult to as- !d io 1977-that phate elementsof some Sweetognathzsspecies sesswith information presentlyavaitable. It is E closely related but differ in having one or two additional sub- possible,of course,that Neostreptognathodus t to Hindeodus. parallel rows of somewhat rnore irregularly representsa stockdeveloped de novofron Di- lis suggestionis pustulosenodes latenlly. Rabeignathus,which plognathodus, whose stratigaphically discon- b oldest named almost certainly developed frcm Sweetogna- tinuousrecord extends almost to the end ofthe tphanus, is sep- thus, has a r/ery short range in the Early Permian. e of L. commu- Permian. The Late Permian Pa elementsfor which !trt to the entire Homoiranognathus wasestablished by Ritter Kozur, Mostler, and Rahimi-Yazd (1976)es- d interpreied to (1986) for a singleEarly Permian species(1L tablished Iranognathus arc, in many respects, nillion years of huecoensis)known only from carminiscaphate homeomorphic replays of those on which xt of this infor- Pa elementson whoseupper surfacean aden- Ritter (1986) basedHomoiranognathus. Evo- r. b-vnoting that ticulate,pustulose median ridge is flankedlat- lutionary patternsin Permian stocksare cur- l9E2) have illus- erally by two to four subparallel rows of pus- rentty diftcult to reconstructbecause collec- elements from tulose nodes. Elementsof H. huecoensisare tions from criticat intervals and facieshave yet l eastern Canada surelydistinctive in appearance,but I am not to be madeor describedin detail. However,it .7F Puesru1Puasn^ JOSluellIele eql qsmSu[srPPFo^\ l3q1seJnl -Ec Jo sesnl?Jeddv's1Aor esorll Jo Joqto "d IsaunJsds el?JBdes -"eJ Jo uorlEurqurocluEcgruSrs ro eql Jo^ueur euo qll^l snonurluocoq l(Eur1I Jo 's,ltroJ | :qlrJsE plno^\ I ar$Eal olSurs,(u? ol lurod 01llnslgrp ^lJ?lncru?d 1rpug I ulroJleldrouolsod o/$ eqlJo spuorouelu? aql 'luenguoc 'uerrrJed eql Jo uud Je^{ol oql olur u?ue^ uea^{leq elsrpeurJelur lurod ? le urJoJlEldaql rx urroJl?ld pul8 -I,(suuedeql qSnorqlsetuer pua uerddrssrssrll urof i(Eurepelq eql 'pue rouelsod sll tv urJoJ r:q iBtu epslq oql lselEl eql ur Po Io^e qJrq 'vrypu8oppY Jo -t"ld roualsod pa^{oJ-elqnop ',{rolJ?u ,{ ?lo t snqlDuS pu? 'uBrddrss$srweqlJo do1eql ot pr?^{dnsen s pue ep?lq aar.yroueluz 3uo1fla^u?leJ ? t9 _sal'.zds -ue8 IEOTUOJUr SEelaq^l -urtuoa ptre srultDuSottldDJJo eeuert\|Jo ued qll.r stueulele el?qdecsurtl$c Pe \oq [q peld t\utf srtqlDuSolapY alq eql q sJeodd?qcrq.{ 'snqlou3snan3 qyil. -ntco sr uorlrsod eql pue ssecoJdJouelsod "d Ele Ed 'uorlrppE uI osecoqt osle sr sql uJoJl?ld Jouolsod pe^\oJ pel?Fcrtuep'3uol s"q tuelrjele?S alqe egt " E snqt pus tusJs,urp -olqnop aql go urtreur fqtu eqt srrrJoJtpql qcrqa ur sesnl?rcdde IEleIa{s elsJqlueu.Itxes elE pueq Jeqlo eql AroJeql Jo puo JoualuB erll qlr^\ snonuuuoc sr paurroJaraq pepnpur sluoPouosepIuIPoIJ€zo Pd puE epqq pue qcrq,yrur |' Ual rqSru oql Jo Jouelsod oql slueur 'sapoqv roq 6uraq ,{lelos ed sercedspqleuEsn-{?c sepnl3 I96I -olo tlrnq l?q1 puo uusnvaoplr1lDu8snv) tllutDl ZI'6 5 r ed gel Pue^q lqtu -ur 'euoz EtEInua0 Joddn-Erlorlsosluerddrs D uqrqxa f llueDd -srssrlI Js,'ao.Ieql olur pJe,$dnsoEua oslBpuD D SafnteJ?ddv ,slrryl snqtouSolt9dueql ralEl tlq [Iuo ueruo^eo 'eprurpolJszoaql Jo'osle " v) 'snqpuSoptl) oql rrr lnqep slr epeu qcrq^\ 'snqpu8DpqJ 'pue ero pelffIu seullqloq Jo uo4curlxosnoeu 'Io OIJUoU -?rodueluoJ i(IJEeuuaq^l 'rrssBUJlsorlJee egl -et eql uo ecu?rgru8rsJreqt Jo I?cqdoISru? I olul ueruJodpue snoJqruoqJEJegl q8noJql 5tu tnq'snueeelx"s eqlJo sercadspeleleJ ,{lesolJJo , lpoteeder,,8uqt srl pp,, qcq^\ Jo qr?a 'se8Ee sluoruolo?d eql qsmEuqsrp01 luerouns ,(Fr?t -v\ snpoqwuSoldle pue snpoaputq-Durpol -JJCeJB saJnlEeJ asJqf'luenuuoJ J3 -nzo er+ 'eprurpolrezo oql Jo se8?eurlJoferu l?ql sapouJo s^ioJ I?urtJ"ur Iellendqns^ll?rolEl o^il ,(q luJla.Urpor(1Jo srJqtuatu pue Jql luJseJdal D)t) peJEIdoJeq ielrr srultouSlwnlldrJ Jo sluoru -nsr Dna)rz.tDslpue srloztdlt snpoaputH leql -olo ur selcnuepJos^{oJ purSffu] oqlJo euo sr uoq?laJfuolur](lo{ll eJourV snouecr^eJe,{\ w s?eJeq^{"d 'epqq ee{ eql u€rcur reddn agt pJeuo8o^\l erll serceds slueuralarruoJl Jo Jo Jo Jo eruord oql u [luo snqpuSotl ?d Jo esoql u]o{ -ru"Jl"ql (sreqloSuour? 'oIII (q) peunsseueeq tu n$W snqpuSnqSol) Jo sercedsJosluouele ?d sEqlI o?prluopoqt"vtr\.uV aWJo snpoaputH 'eJeue8rnoJ eql Jo uoqpndes elqertoJe loo.De (n potrs ueeq .{F?uolsnc seq D aninsl Jo I,tn6or"pV ol llnsgrp ,fio^ 3q pFo^{ lr uoqnqulsrpsrgd?r8 dllsecueecuer{ :Jrss?ul lsellleoeql Jo u?rurrad -rle4spunfsrp sql JoJlou eJe.trlrJI JoqEqeuo lsalElfto^ egl roqlra luo{ paqursepueeq s?q lxeu eqt olur etuEl ro euoz teql ot peuu snpoqtouSoldlo oN ?uuec eql Jo seprs qloq -uocDqlre eJe^luopu? 'u?rddrssrssql eql ur JeqEq Jo euo uo dsn3eql Jo $[ueu IBJoleluo pedole^ seuoz o/ru euros 'euoz snuexel aql ur Jeed -epeq Feu elonuappcruo3 elSurs ? pu? 'qlBuel -d? dnoJ8srqt Jo Ejeuagreqto eql '.eaozewq llnJslr roJ pol?lnJrluep sr ?uuEJ uErp3tu eldturs w reddfl-€rlJrlsosluErddrsslssrl Je^\o'I aql et$ "fiq'snpoqwuSoldrO osoqlol -ueJC l Jo t3ads?[Ere olur setu"J pu" u?ruo^eq 4".I eql ur peJeod -1e[ur J?lrr[rsere serceds lu?uodur -de snqtouSottod s,r\oJalcDuop purtreru on1 -rlells slql Jo slueuraleed JleqdEJsrurr.ureJ^lecrqder8 @ slr uee?$leq4erpeuuelu lurod le ruJoJl?[d 'rrss?LrJtsorlreo or{1Jo (99'9 '3r{) (epeplcnH) " eql Jo puo rouauE eql surof opElqeql qJrq^\ DJtz.tosto aJrJtosJol pedsgJ qlr^\ pal?clld uI sluouolo ?d peurroJ(/S'S 'EICuI pstertsnl -rrpere sru.lpu&our.qJosdrqsuo4eler pue ur8r -[ 1ne)sn{Du8oqdn1 pue 'snqwuSlutort.tdDJ -ro aql SurleJtuaulqlP\ pet?rJossesuelqord 'snqpu8nqSolJ'snqpuSoltDd Jo sorceds 'uerrured lsq.el eql ar snpoqtDuSold P 'soJnleoJcrAoloqdJorrr Joqlo ur Jo uorl -!O ruo{ tueudole^ep crqfuouoeruoq pa^II tde7 -elnolluep Jo el,qs pu? ezls ur JeJrp Jr?d -uorls E sluaserdajsnqeuSountl t?ql (rseellP e srequreur pu€ ro '/rroJ^prllruJoJleld ol) oJoujsr 'uerdul€TloA\elel eql -outo Jo UeJ lqtu 'eur U aur?ser0Jo pua Jouelu?aql surofs^?^\l? epelq ar Dtrq$^lo{rT snqpuSoiaa,lrs',{q pou^\Eds se^\ qcq,r eqt q8noql uo^o suorpeJrpolrsoddo ur peaoq ')4.aolssnqpuSouottoutoH etll Jo suownuDuoc eq JI?d€Jo sJequeurgel pue lqEu 'sr l?ql cqauaSotfqdlueseJdel snqpuSouD.tl uewJred w :,{Jleluul,{s^eru III sseJJlrqqxe sercedsprqleutsn^ e1?-IJo sorcodso,,,(rl oql lEqt,{[e{rTun sruoos VJNOOONOJ:IHJ THE MAJORCONODONT CROUPS t2l liss III symmetry; E of a pair may be r e\ en thoughthe i end ofthe same H membersof a ClogheEnathus rlle of denticula- 4ftarures. ; Cloghergnathus, frognathus (all il- d Pa elementsin lerior end of the ldiare between its . Patrognathus ap- I a-ndranges into iia-Upper Cren- r of this group ap- , some two zones ld are either con- ch- into the next lis disjunct strati lbe very difficult to Adetogntthus f tbe four genera. ghergnathw differ o\' in the profile lce blade,whereas ra'nticlesin Pa ele- l ma)' be replaced Ess of nodesthat I features are cer- Clydagnathus I the Pa elements b samegenus, but Fig. 5,57. Elementsand apparatusestypical ofspeciesofthe Cal.usgnathidae. l:nce on the ge- b its debut in the Clydagnathus, Cavusgtathus, and Adaogna- periencewith thesegenera were it not for the tha, Patrognathus lruJ. Apparatusesof Cavusgnathusspecies ap- fact that specialistson Carboniferouscon- rtbe Lower Missis- parently exhibit Class IIIa symmetry in that odonts appear to have problems lhat arc aI :nulata Zone, in- right and left Pa elements are distinguished leastas great as mine! In any event,elements of r lhat built Pa ele- solely by being bowed in different directions. cavusgnathidconodonts are common in rocks r end of the blade Right and left Pa elemelrtsof Adetognathus,on that recordmarginal marine environments that fix end of the row the other hand,are morphologicallysomewhat werecharacterized by shallowwater ofvariable h of the double- differentand thus exhibit ClassIIIb symmetry. salinity, and they are useful as guides to such his is also the case In addition, Pa elementsformed by speciesof environments. Eears in the late Adetognathushal/e essentiallyno fixed blade, Ancestorsof caYusgnathidconodonts have mft4s and contin- whereasin comparablePa elementsof Cavus- beenidentified by Sandbergand Ziegler(1979) Mississippian,and gnathus srycies as rnuch as half the length of in Late Devonian populationsof spathognath- *Yed in the latest the blade may be incorporatedinto the mar- odontid ozarkodinidesreferred to Pandorinel- mugh the Pennsyl- ginal platform row with which the blade is lina insita (Stauffer).In thosepopulations, Pa f the Permian. confluent. elements (Fig. 5.38) are dominantly single- o any single feature I would ascribemy consistentinability to rowed,carminate pectiniform structures with a mbination of fea- separatespecimens representing species of Ca- prominentfinlike bladethat is deflectedto the Ite Pa elernentsof vusgnathusand Adetognathus to rny lack of ex- rightat its posteriorend. However. minor seg- Pd (t86I) urgrls f]jlJ-le!) srypuSoptl) ruo{ pe^lo^e snqnuSol EfrrH Jo -san ll.tll (9961) pr?qcro pue Eroqpu?S'raulg rEJeuuoc ^pnlsuI uo^ ot slse88ns',{lpcuaueSol.{qd lueurdole ep ;:I" ereu98osoql s1rur pecunouo:derorll sauroceq oslp JelJ€r?qt rE 9S6I 'rea^S re .el aql leql lceJ eql gll^{r raqta8ol 'srql uI8 I pu? uosuerg -J?ruIESsq e^rss3coJ Jo seuozou pu" secBJjns pJrslar repun eleqd?csSur^eq ul snqpuSsno) tlnpe lrpalnoaN^lqFsod pue Jo sluelllele?d ot ,{Jl?c€oloqdJourrzlrrrlrs eJ? 'T€6t 'lqel^Ipue setoadssnlpuSotsaw Jo eqt ur seAels u sr ilrruq srql ,(lJ?a tuosoJdoJleqt slueuelo^ueSoluo ?d 'lrd [es?q eqt ol Jouelsodpue IeeI ,ftBurud eql 01 Ipura ,61 lqaw -Jsur ur8Jerupseq e^rssoceJ seuozJepeo.lq J I 0I'9 Jo -qtutD! pue JapeoJq pnp"l8 pu? :laa{ Jo luaurdole^op loepqleuSotsel l) szIl lDuSo$an Jo luew F--l ropro ol's fu"puooeseql Jo uoqlugep Surs?erour:qJlou -ole ed Jo s,{er repun pue 'op$ 'Ioddn '8S'9 '8Id " rouelu? orllJolueurdole^ep ur gs?ejcurpnp?ra ? :ur8J?ururoJl?ld Ual orll Jo tueul8estedEr?d 'snl?J?dd" eqtJo Atoloqtuouj ur a8ueqcpnp?Jt pe^Io^ur -trg uo^ ,(q,{pnls srqda€ouoru luocoJ dJe ?Jo I Jql fluo pezl snqpuSoisal4tlo tueudole^ep crloueEolr(qd sFefqnsoql eJ" '.{lrueJsrrllJo slequreu u^\oDI j:i+ p:JesnqpuS lueruEes lede eqt elnlusuor qclq^\ '(89 S 'tlJ) (rs6l) pu" pue qteouoq dlJq ,{erII lueu -red euum aqlJo roueluEeql ^IuoJJo\asrg snqrDuSotsrJrfJo serceds a^g eql I UOIIJUISaJleql pedole^epsr 'o^ooJ8u?Ipolu eql Jo qcueJqe 'sapoqY ?Eqpu"S 'rellrg apnlour[?ru qcrq r 'leel fu"puorasV '(pJeqrJO I86I puv u4snvanplrltDaSotsaI4J (ttrutDl EI'69 d nr .{q petrq?q pue SJoqpu?S'Jellrguo^ uorsJa^e,, lEqs aql Jo pJela us peluJol) urEJeuJI3s3q ^q,.dr!s e^rssecoJ Jo seuoz gq .iq pozuelce /rlolEu lld eqlJo JouelsodpeJepJoq $ pue '€pluIpolJ?zo aroqsj?au 'qsJEq qlAuopru^q Jo rouatu? lrd ps"q ["Ius ? sesolc eql Jo seE?eulltueJe.grp snorr? uI peldop" I mqrouSo$aw -ue qcq^i leel u"rpeur pe^ooJt ,(q palr"ru sr ,{lepl,|alueludole^ep Jo uJe Bd eql " f, luopouoc qceo stuerl.Ialo?d sr?{/ru8o$aw Jo eprsJepunoql s?/i\ 1r tErll p"J eql loJ ld$xe Euruonueur^lreelc FJo'.qUlrqrssod '3tu?uootul quo.4 aq lou plno,,A,{trJrqrssod srqJ sJotseju? rsrt/drJs' JoJ oslE clruouoxn rarurardutrss" (986f) pftqcJo puE puruouuopuedpetuouncopun ro poullueprun I eq pFo^,\ fJloru 'SreqpuEs 'ro rg uo^ qclq \ ol loda?d pelel te, s? rrIolJ {1e,r4ere1rpedole^op (mqlnu8n \rseq Jqt ,(lqrssod -nJrluep,{le^Dcurlsrp ? otur pedolo^epsr ule -Ll8ol) pte'snlqou8tutDrtdD)'srullDuSoiapv F Edase ur pal€p -reu elrsoddoaquo pueroueluE aql 'uuoJteld -mqnuSsn^D) 'snqpuSoqdDJ ''a 0 spqleua [ 'gtuouroeruoq eqt Jo urfu"u rq€u p3Bpu oql qlv( snonu4 -sn^EcJe13l eql 13q1lno pe[u oq lou uec 1ros DpoqtEutoql?dS -uocsr'qltuel pnbe,(leteurrxoJdd?JoslueuEes 'Je^e^\or{'slJols prql?u8sn^?JJ4"l eqlJo sa^4 tsoddns I '^lsnol paxs pue eJ{ olur PePr^rpsr r{Jrq.n'Jpelq aql -Elueserdar $rg eqt uro{ snqpu8DptlJ pue €alRJ JuoueEBJd 'uuoJt€ldequo drl rouolsodaql ol spuelxol"ql snqtDuSo.tlodaleJedos,(lluoJJnc sdEC qcueJq EEoJ rraql pue) puu"o lErpeuqns leulpnlrtuol e ruo.g sqtnorl snqpuSopq) et+Jo std.olrcnu\ttd.o}ere'sntlpuS seqt Euwpour I€uumpe [q poterzdese:e 1eq1surSreru peAplJ -otapv 'ratel 'pu9. snl ou8sn oJ leql pue '^lr q'snqpuSo$aw ,{IssJe^su?Jt'paulnldn,(Dq8rlsqtr^{ uuoJl?Id -urE orpJo qtu?Jq snqpuSolpd eqt vrorJ etJrrl r!) a?prqteuAsn^ ped?qs-Arouelsod z pue ep?lq roualue qErq usrddrssrssrll-pllu ur pedole op snqpuStu g-.\aJ pu" ,tpnlseJ E qll/'( soJnpruls ruJoJrurlcedaleueldrurlujsc -tnudDJ pue'srulpu8nq8ol)'snq JouSoqdoJ 4rsall'Jo Jolso3uE ere serceds snqpuSo$aI,4{Jo sluarxele ed l"ql ssonE1q3[u ouo urroyeld eql Jo eprs plp s€ '(8€ 'urJql PaurJoJleql sluoPouoJJql fq pezr lqEu eql uo ssopoueql glr^\ snonunuoc ? s ^\oJ qI ueruo^ecl el?'I l?Jeulur ele^r serxedssnlpuSolsal[ Jo sluaur sr ePsJq eql sluauJaleEd Jsoq^r ur 'sr?{,| qr sr qsrq^\ 1[?'s -ele €d eql i(Iuo osn?caqJo sasnlEl?ddeeleJd -DuBDpqJ ol Jo 's,r\oJpurS:eur o,lrr1slr uee/(l S qll-,t' clqfuour -uoJ tuqcn4suocoJJo qof egl 01 el?nbepeur -oq [uJoJl"ld eqt surof teqt opqq ? qt[^{ '.snryl D SluJurele3d JJe,rsuorlJelloJ JIqplrE e JsnEJJqJeqlla 'sJrJ -DuSottDdot Jaqtreesu ue^6 o^"q ot tq8noql ru tq8u aql sulof -edssnqpuSotsal I Jo slueurela?d eqlJo uounq eJe eseql Jo sluEU?A 'epelq eql 01 Jouel ror-Jlqnope e^?q -ul.slp pu? '.tuetotuo ',Goloqtuour uo sesncoJ -sodselcuuop e{rlapouJo s^1or elqnop podola^ '(asptl{l?u8sn^eJ ,{pntstErIJ (986I) preqcro pu? 'EroqpuEs'rol -ap suoq?Fdod au?s eqt Jo stuour ^llusJedd? VJNOCONOJ AHI zzl THE MAJORCONODONT GROUPS t23

[t986). That study Cavusgnathidae),whose scaphate Pa elements [en1. and distri- havea double-rowedplatforrn and a bladethat Ydtognathus spe- joins the right maryinalrow. b collections were Pa elementsof Mestognathusare homeo- Drxsfucting com- morphic with those of Scaphignathus(Fig. E onl) the Pa ele- 5.41),which is thought to have evolvedin the h qere mineral- LateDevonian from Pandorinellinainsita (Fig. imed them. 5.38;- as did Clydagnathus,the proximale drzs species are ar\cestorof Mestognallrus.Short of a thorough *rucures with a restudy and revision of Pandorinellina, the Ca- merior V-shaped vusgnathidae (including Clydagnathus), and, Fig. 5,59, Elements typical of sp€ciesincluded in the d- transversely Meslognathus,however,I see no way ofaccom- Coleodontidae. ned by adcarinal modating these remarkable homeornorphs , srbmedial carina (and their common ancestors)in the samesu- fu of the platform. pragenenccategory. Thus, somewhatanoma- iro fiee and fixed lously, I suppose,| rctain Scaphignathusit the is difficult, if not impossible,to diagnoseprop- Fal length,is con- Spathognathodontidae,whereas its younger erly becausethe type-speciesof Coleodus,its ts margin of the homeomorph, Mestognathus,is accommo- typegenus. is basedon fragmentaryspecimens flte oppositemar- datedin a separatefamily, the Mestognathidae. that make comprehensiyemorphologic inter- irdvely denticu- Possiblythe bestway to insuretaxonomic sym- pretationimpossible. In general,howeyer, spe- Bitter. Sandberg, metry would be to establish a separatefamily cies in this taxonomically isolated group Rmjer taxonomic also for Scaphignathus,which would raise the formedrelatively large elements that havehya- possibilility,of course,of a separatefamily for line, fibrouscrowns, which (in the caseof,S/er- irui Pa elements eachconodont genus! eoconusand MixoconuJ) consist ofrobust con- in keel,which en- Mestognathusis interpretedas a denizenof iform elements or chains of such elements rior of midlength harsh, nearshoremarine environmentschar- weakly (in the caseof Archeognathus)or stoutly '6e pit by narrow acterizedby high saliniry and probably land- connected(in Coleodusand. Neocoleodus) with rgln (termed an ward of the shallow,inshore environment in- their neighbors at the base. Undersidesof lr. Sandbergand habited by its progenitor,Clydagnathus- von crowns are flat, broadly convex,or longitudi- ficb may include Bitter, Sandberg,and Orchard(1986) speculate nally grooved,and in numerousspecimens of s!-e. is developed that restriction to such an extreme envron- Archeognathusand, Coleodzs crowns surmount b carina and par- ment may help explain the rarity of Mesto- a prominent basalstructure that consistsofan gnathus and.the fact that it may have mineral- elongatebar that exhibitsa conspicuousdown- l of f{estognathus ized only the Pa element$ of its skeletal ward projectionand apparentlylacks a cavity roryhology of the apparatus. or excavation.No basal structureshave been ladorm maryin; a observedwith elements of .S/ereoconus,Mixo- Ent ofthe anterior conusor Neocoleodus. of the secondary 5,10 OrderUnknown Barskov,Moskalenko, and Starostina(1982) lt ofbroader and illustrate numerous bonelike featuresin the Bransonand sal margrn mar- 5.10.1 Family Coleodontidae basalstructure of Siberianspecimens referred Mehl, 1944 d posteriorto the to Coleodus,bntK)apperand Bergstrdm(1984) I rEpresent early This family is retained for Coleodus Branson were unable to identifi, comparablefeatures in Aognathusspecies and Mehl, 1933,Archeognathus Cullison, 1938, the basal structure of Archeognathus.Altho]j;gh b Pa elementsof andNeocoleodus Branson and Mehl. 1933.and the crownsof elementsassignable to speciesof E scaphateunder possibly related forms such as Stereoconus the Coleodontidaeclearly exhibit the intemal =sive basalmar- Branson and Mehl, 1933, a.nd Mixoconus structure of conodonts, the basal structures hct that the latter Sweet, 1955.Elements of speciesassigned to have no counterparts elsewherein the Cono- lronouncedin its thesegenera are shownin Fig. 5.59. donla. 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YJNOCONOJ IIHI tzl THE MAJORCONODONT GROUPS furdse Acad. We- dolta- In Treatise on inyertebrate paleontology Gagiev, M. H. (1979). [Conodonts from the De- 54, Pt. W, Suppl. 2 (ed. R. A. Robison). ceol. Soc. vonian/Carboniferousboundary deposits of the rt. B- (1979).Sta- America and Univ. Kansas,202 pp. Omolon Massifl. Guidebook, Tour 9, Biostra- : Palmatolepis ap- Cooper, B. J. (1975). Multietement conodonts tigraphy and fauna of Devonian-Carboniferous doDlophorids) at from the Brassfield Limestone (Silurian) of boundary deposits. l4th Pacifrc ScienceCon- d specific level. southern Ohio. "/. Paleont. 49,984-1008. gress,Khabarovsk, USSR, August 1979,Suppl. - (19'77\.Toward a familial classif,cationof 2, 104 pp. (In Russian,\ryith English diagnoses 1r5 from the Fort Silurian conodonts.l. Paleont.5f , 105?-1071. ofnew generaand species.) Horician), Mara- Cooper, C. L. (1939). Conodonts from a Bush- Harris, R. W. (1964).Subgenera of the conodont {3(5), rc- ll37- berg-Hannibal horizon in Oklahoma. "l Pa- ge\!s Multioistodus in Simpson-Burgen (Or- Ieont. 13, 379-422. dovician Arbuckle) conodontsf.om Oklahoma. 4h1.- and paleon- Croft, J. S. (1978).Upper Permian conodontsand Okla. Geol.Notes 24. 108-lI8- Fatr of Missouri. other microfossilsfrom the Pinery and Lamar Harris, R. W., and Harris, B. (1965).Some Wesr r IJ{3). r-208. Limestone members of the Bel[ Canyon For- SpringCreek (Ordovician Arbuckle) conodonts - C- | 1947).Lower mation and from the Rustler Formation, west from Oklahoma. Okla. Geol. Notes 25, 34-4'1- lEk\'. J. Paleont. Texas.Unpubl. M. Sc. Thesis,The Ohio State Harris, R. W., and Hollingsworth, R. V. (1933). University, Columbus, 176 pp. New Pennsylvanian conodonts from Okla- ; G. ( 1933).Con- Drygant, D. M. (1974).Prostye Konodonty Silura homa. Am. "L Scl., ser. 5,25(t47), t93-2O4. dodts from the i nizoy Devona Volyno-Podolya (Simple con- Hass,W. H. (1959).Conodonts from the Chappel rado: Bainbridge odonts ofthe Silurian and lowermost Devonian Limestone of Texas. U. S. Geol. Sury. Proll Do City (Lower of the Volyn-Podolian arca). Paleont. Sb. Lvov Paper 2941,365-40Q. jr- -llissouri Stud- Univ. GlO, 64-70. Helrns, J. (1961).Die " nodocostata-Gruppe"der Dzrk, J- (1976\. Remarks on the evolution of Or- Gattung Polygnathus.Geologie t0, 6'14-'71t. G no. 3: Con- dovician conodonts. Acta Palaeont. Polonica Huckriede, R. (1958).Die Conodontender Med- Shaleof Missouri. 2r,395-455. iterranen Trias und ihr stratigraphischerWert. l?l -159. - (1983).Relationships between Ordoyician PalAofi.2.32. L4l-175. rlJs lcriodus ard Baltic and North American Midcontinent con- Huddle, J. W. (1934). Conodonts from the New I J. Pateont. 12, odont faunas.f'offils and Strata 15, 59-85. Albany shale of Indiana. Bull. Am. Paleont. Dzik, J., and Drygant, D. M. (1986). The appa- 2r(72), 136 pp. 233-246 i\ Index ratus ofpanderodontid conodonts.Ielrara 19, Jeppsson,L. (1974) Aspectsof Lare Silu- \I lL9'151. E . Shimer and r33-141. rian conodonts,Frssils and Strata 6,19 pp. 'aL Ethington, R. L., and Brand, U. (1981).Oneotodus - (1983). Silurian conodont faunas from ft. R. (1983).Pae- simptex (Fumish) and the genus Oneotodus Gotland,.Fossils and Stratq 15, l2I-144. a frmily Icriodon- (Conodonta)."/. Pqleont. 55, 239-24'1. Kennedy,D. J. (1980).A restudyofconodonts de- lifiw. Fossilsand Ethington, R. L., and Clark, D. L. (1982).Lower scribed by BRANSON & MEHL, 1933, from and Middle Ordovician conodonts from the the JemersonCily Formation, t-ower Ordovi- *t'oniar. Icriodus Ibex area, western Millard County, Utah. cian, Missouri. Geol. et Palaeont.14,45-76. nl. et Palaeo . 6, Brigha.m Young Univ. Geol. Studies 28(2\, t- Klapper, G., and Barrick, J. E. (1983).Middle De- 160. vonian (Eifelian) conodontsfrom the Spillville fuatigraphie und Fahraeus,L. E. (1984).A critical look at the Trea- Formation in northern Iowa and southernMi[- es der dstlichen tise family-group classificationof Conodonta: rrcsota.J. Pq.leont.57(6), 1212-1243. ial ){. Jb. Geol. An exercisein eclecticism.Lethaia 17. 293- Klapper, G., and Bergstrom,S. M. (1984). The 305. enigmatic Middle Ordovician fossil Archaeo- rr. D. G. (1977). Fahraeus,L. E., and Nowlan, G. S. (1978).Fran- gnathus arrdits relationsto conodontsand ver- conodonts from conian (Late Cambrian) to early Champlainian tebrates.I Paleont. 58,949-9'16. 51,'772-796- (Middle Ordovician) conodonts ftom the Cow Klapper, G., and Johnson,D. B. (1975).Sequence 'ar. [tte multielement Head Group, westen Newfoundland.. J. Pa- in conodont ge rs Polygnathusin Lower De- trs. Doliognathus leont.72, 444-47L vonian at Lone Mountain. Nevada.Geol. et Pa- .- 59\2), 299-309. Fortey, R. A., I-anding, E., and Skevington, D. laeont.9,65-83. ria.n crisis and its (1982). Cambrian-Ordovician boundary sec- Klapper, G., and I-ane, H. R. (1985).Upper De- coDodont taxon- tions in the Cow Head Group, western New- vonian (Frasnian) conodonts of the Polygna- t7-158. Clark, D. foundland. Pp. 95-129 in The Cambrian- /ltis biofacies, N.W.T., Canada. J. Paleont. l 2). Suwey of Ordovician boundary: Sections, fossil distri- s9(4),904-951. r North America. butions,and correlatioflJ(ed. M. G. Bassettand Klapper, G., and Murphy, M. A. (1975).Silurian- gudies 9(2), 102- W. T. Dean). Nat. Mus. Wales,Geol. Ser. 3, 27 I-ower Devonian conodont sequencein the pp. Roberts Mountains Formation of central Ne- teqstrom, S. M., Furnish, W. M. (1938).Conodonts ftom the Prai- vad,a.Univ. Calif. Publ. ceol. Sci. ttl, t-62. Rhodes,F. H. T., rie du Chien (I-ower Ordovician) beds of the Klapper, G., and Philip, c. M. (197D.Devonian yalley. , Lindstriim, M., Upper Mississippi J. 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VINOqONOJ lHJ hren des Silurs. brforsch. 41, L- t- s'. (1986).Pa- f rhe Phosphoria 6. EVOLUTIONARY PATTERNS 'our. Geol. 24(2),

Fnten der Eifel- knchbarten Fa- t Lahaea 5t, 6.1 Introduction databases that are the enq' of their peerswho 1979)-Evolution- studylarger fossils. This is duepartly, I believe, b mnodont gen- As noted in ChaptersI and 2, conodontsoccur Cteol-et Palaeont. to the caution automaticallyprovided by very abundantlyin most typesof marine sedimen- largepopulation samples from stratigraphically rg des hiiheren tary rock; they are widely drstributed geograph- well-controlledsequenc$. In someparts ofthe ! im Gebiet des ically; and, as a group,they have a long strati- geologiccolumn, densespacing of large sam- mit ) Hilfe von graphic range. Consequently, conodonts are ples provides an almost continuousrecord of hnt. Abh. 127, exceptionallyuseful as providers of biostrati the developmentof populationsthat can be graphic Devonian cono- information to geologistsinterested in seento have had and to have rnaintained very fr.le (?) of Iowa. a broad spectrumofproblems, and thoseofus great internal complexity for appreciableinter- who study conodontshave expendedmost of vals of time. Not uncornmonly,it is difficult or ! und Phylgenie our efort in supplying biostratigraphic service irnpossibleto expresswhat we know about I und ihre stati- to the geologiccommunity. We have had little populations 2x- I-andesamtes such within a generally accepted time left over in which to addressthe more es- systematic framework that yr'as designed to Eh-\' of the Eu- otericaspects ofwhat might be consideredtruly handle a rigidly typological taxonomy. And Llt Symposium paleobiologictopics. this, of course,has resultedin hiding a good w. Fd C. Sweet, On the plus side, however,our serviceori- deal of very useful information in categories z Mem. -lmerica entationhas resulted in the assemblyofan ob- namedand treatedas speciesor generain ac- jective, f conodonts. E if widely dispersed,data base,which is cord with principlesestablished and rigorously lhandlung 3, l- several orders of magnitude larger than that maintainedby Ihe InternationalRules ofZoo- availablefor any other group of Paleozoicor logical Nomenclature. Johnson, J. G. Triassic "macrofossils"and is also one that But studentsof conodontshave had addi- ivision yar- ofthe may be viewed within a biostratigraphic frame- tional ts?Upper Devo- excusesfor caution.That is, the subjects Jn€Iicz. Geol. et work currentlycapable of resolvingthe 300-my oftheir studyrepresent a groupof animalsthat history ofthe Conodontainto 152divisions. In evidently does not occur in the living bio- ll9E7). Cycles in addition, of course,we now have a fairly clear sphere.This means,of course,that thereis lit- Fonian to mid- idea that recurrentgroups of morphologically tle unequivocalanatomic information availa- b, Palaeobiology different element types are more suitable than ble for idge). .Ellis Hor- conodonts and that biologicalty individual elementsas the basis for species- meaningfulsystematic and ecologicconcepts t (19E4). Palma.- level taxonomy;and, as I havetried to showin must be generatedquite indirectly r IEfl of standard Chapter5, speciesmay now be assembledinto Now, however, there are in place at least the lion. Geol. Soc. supraspecificcategories that provide consider- broadoutlines ofa defensibletaxonomy, and it L ableinsight into the patternsofconodont el/o- is probably d R. L. time to take up the biologically -\ustin, lution. At present,our organizedcollections (and philosophically) shodus Etoup challengingtask of evo- Devonian and provide little information as to the modesor lutionary interpretation.To this end, I assem- c, Pelaeont. 8, processesby which evolutionarydevelopment ble in this chapter some observationson the was effected,but pattemsmay ultimately sug- evolutionary patternsI recognizein the 300- gestprocesses that may also be testedagainst my historyofthe conodonts,and commentson the objectiYeevidence. a few examplesthat seemto suggestprocess as Micropaleontologists,as Lipps (1981) has well. Perhapsrny observationsand comments emphasized,are not noted for generating,test- will proye sufficiently outrageousto stimulate ing, or evaluatingfundamental paleobiologic more penetratingstudies ofevolutionary mode hypotheses,despite their accessto finely tuned and process.I hope so. o : e

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E ueurod pogn I ueql pr^lo^o^q serc IEJ puEueruo^oc Jepro'lsrgt Jo uopru8mor lnuad sSoloseql -oO eq1 ul peautocer .{eql souo orTo,bsql ol 'uoqryo^a FaIf,edS 'Z'9 'A!d lo xapurue s? pasn(z16l ) J?lrurssurel"d l"ql elou plp ,(oqltnq 'ueunlrs ^le^DceJe {relC qclq,{r 'orl?J uortcunxe-uoq"ur8uo oql el?l uslll replo Jo uerddrssrssrll u?ql retuno^ ur suoqEnlrnu s^{oqs l?qt tol ? epnl3ur osle sluopouorJo ,fto$rq fuEuorlnlo,\a eql uI slue^a '8 9 pue 'Z'9 'I'9 'selg q peprdop 'stol eseqJ reprsuoctou pIP (186I) ou"-I pu? relSorz '?luopouoC eqtJo sErr?Jcrss?uI q8noJql u"uq 'e?p4uopoucl -III"C el"l oJrlueeql JoJsrs"q euoz-^q-euoz? uo eppuoporuoud eqt Jo ,fuolsq eql ur slue^e^Iru?J ,{lrsra^rp Ie^efserJadsur suonenlcnu rrorls l"ql uI lg 01 osl" eperrr sEArldurell" uE '$Iools stol eeJqt lueserd I 'eluopouoC eqtrJo fuolsq Jprurpo{r"zo snouE^ Jo luorudolo^ep o^u dJ?uoBnlo^ooql ur slue^erof"Iu eql Jo eruos -?Jelr eql uI sote$ ol ,{le8EI selc^J eseql pet?l Jeld?qcsrql ur SururruBxoJoJ srsBqaql sV -er eue'I pue JelSarZqtnoqllv 'uorlourlxa Jo 'srs?qsuoz-fq aposrdeuE pal?Jurul ,(lol?Iurlln pu? uoq?^ p -ouoz uo sarcedsluopouo3 u?unlJs pue u?rc -ouul Jo lsrnq^q Uoqs e ,{q pernpolur $ qrrq^r -I opJOJo ,ttrsJe^rpeql ,'Aoqsof (98611eo^{S) '&lsre^Ip Jeq8rqJo euo pe,{rolloJsr ,{lrsJe^ ,{pueceJpelrduoo I l?ql Eol e seop se 'selc -rp,{iolJo Ie relur uE 'paqucsop.{aql^q salc,{o xrs -l(c ,{lrsJe,\rpJo uorssoccnspelloJluoc Jql Jo rlcEJul sluoPouossnoreJruoqr"J /tlrea ^lepruc " ,{.oqs osl" ?rousEuuoJ luopouoc Jo uorlElnqel pu? upruo^oo Jo luourdola^ep,fu?uoDnlo^o seues-,(q-seuese uro{ (Z16I) Ir"IJ ,(qpaprufs eql uI lrrall"d 'cqc,{c Jo 'e p[edeJ u peuqlno -um sEo'J'eluopouoCerll Jo,4Jolsr{ uErddrss$ (186I) oup-Ipu? relSerz'^pnts tusJer tue^ ? uI -sq41-1sodpue ueruo,req-ud eql pezuolcpEqc e^?q osl? lqElu u?rddrssrssrwpue uEruo^ suraDBd ,{Usra^!C Z'9

VJNOOONOJ:IHJ 0gI EVOLUTIONARY PATTERNS l3l

+ht also have r and post-Mis- bnra. Logs con- r series-by-series Fnera also show r of diversity cy- Fpiled recently vt-*_v _+ _*_ x _r_ x[ _*_ xfi- rsit-v of Ordovi- :cies on a zone- iin this chapter b evolutionary Isent three logs rs{evel diversity cmire late Cam- hte Conodonta. r-' \v,'.-.,, i7 -1__,.\- il. 6.2,and 6.3, ',// \,,"."' "- t fuctuations in rdm.|..n I v|- - oEvoxratl Mlssrsst?flar{ b, which Clark PEI{I{SYL k ofevolution. Fig. 6.2. Species-diversitylog (upper solid line) and log of origination-extinctionratios (lower dashedline) for 64 Lof 4 first-order Devonian and Carboniferouszones. Stippled segments oforigination-extinction log indicarc limes when more spe- ciesevolved than becameextinct; asterisksildicate times of sigdificantextinction ieparating diversity cyclesidin- tifred by Roman numeralsVI to XIII.

'&hed line) for 40 blog indicatetimes cyclesin conodont diversity and also delineate (of 246 genera)that I regard as reasonablydis- r separating diver- about 20 second-ordercycles that supportthe tinct in a multielementcontext, even though conceptadvanced by Zieglerand Lane (1987). completeapparatuses have been established for The logs,ofcourse, extend that conceptto both only a few of them. Clearly, as additional data earlier and later intervals of time than Ziegler becomeavailable, certain peaksin the diversity and Lane considered. logs may be emphasized and certain depres- In the tabulationsdepicted in Figs. 6.1, 6.2, sions filled in. But I suspectthat the general and 6.3 I have includedonly the 1446species patternwill remain much the same.

Fig. 6.3. Speciesdiversitylog (uppcr solid line) and log oforigination-extinction ratios (Iower dashedline) for 48 Permian and Triassic zones. Stippled segments of origination-€xtinction logs indicate times when more species evolved than becameextinct; asterisksindicate times ofsignificant extinction separatilgdiversily cyclesidentifred with Roman numemls XIV to XX. x l -* - xtv- * - xv -*- xvt_*-xv _*_xvt *xtx*_ xx I

I

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YTNOCONOS3Ht ztI EVOLUTIONARY PATTERNS

eustaticepisodes, and first-ordersegments of eage,which foundedthe Paraconodontidaand, the species-diversitylogs in Figs.6.1, 6.2, and in the very early Ordovician, launched the tst diYersityin 6.3.The simplest,I believe,is to postulatea di- Prioniodontida. Early diversification of the h- in the inter- rect relationship betweendiversity of conodont Cavidonti was also accomplishedearly in Cycle rt€ Ibexian and speciesand the expansion(and subsequentre- I. The Proconodontidasurely reached the acme E whiterockian duction) of suitable habitats recorded by rocks of their evolutionary developmentthen, and i diwersity to a of the transgressive-regressivesequences. only Polonodus and,Pygodus are known from rtre early Mo- rocksdeposited during laterOrdovician cycles. t corresponds in The Belodellida, - 6.3 Second-OrderCycles which I interpret as descen- Dost u.idespread dants ofthe Proconodontusstock, appearedat rdepositedin the Superimposed on the first-order cycles re- the climax ofdiversity in CycleI but werenot America (Sloss, cordedin the logs of Figs.6.1, 6.2, and 6.3 is conspicuouscomponents of Ordovician con- the record of 20 second-ordercycles, each with odont faunasuntil the interval of CycleII. r lme Middle Or- the generalcharacters ofthe onesrecognized by The 40 conodontgenera and 227species that ftersity of con- Ziegler all.d,Lane (1987)in the Devonian and arelargely confined in their known rangeto the ryrdly to a Late Early Carboniferous.By and large, each of interval ofcycle I representtwo groups.One is bllowed (with a thesecycles begins with an interval oflow spe- made up of mostly shortJived experimental in at the Ordo- ciesdiversity in which the ratio of speciesorig- stockssuch as the Clavohamulidaeand Cor- r general decline inationsto speciesextinctions (the "evolution- dylodontidae, which appeared briefly during rian hto the ear- ary index") is below1.0, followed by an interval the initial radiation of cavidont and conodont ildle Ordovician of higher diversity-that is immediately pre- lineages but were apparently not ancestral to : correspondsin cededby an innoyative episodesignaled by a anything else; whereas the other, typified, for r during which spurt in the evolutionary index. Cyclesare ter- exarnple, by Rossodus, Tripodus, and, Prion- Tippecanoe Se- minaledby moreor lessabrupt drops in species lodzs, includesgenera that foundedor are in- Blionh America diversity which, for the most part, seemto be termediate parts of evolutionary lineagesthat, the expectableconsequences ofa declinein the in modified form, assumegreater importance rth America,an evolutionary index in immediately preceding in later cycles.These lalter lineageswere evi- iau rhrough the zones. dently subjectedto more or less continual od by formation As is clearfrom the logsin Figs.6.1,6.2, and, pruning during the prolonged regressivephase c KaskaskiaSe- 6.3, whose horizontal scaleis approximately that characterizedthe waning stagesin North |Fig. 6.2 that in- proportionalto the length of time represented America of the Saukcratonic cycle, so thereis alnost symmet- by the intervals shou,n, second-order cycles no evidenceof their catastrophicor massex- ly Devonian and were of greatly different durations and hence tinction at the end of CycleI. rsiqv maximum seemunlikely to have beenthe resultsof any Note that by early in the Ordovrcrancon- ! nme. regularlycyclic mechanism.As the following odonts werecommon not only in the tropical tia Sequencein remarkswill show,these cycles are complex in- to subtropical waters of North America, Aus- fNorth America temally,and it may be difficult to find a general tralia, Siberia,and probablyparts ofChina, but r and lesswide- explanationfor them. also in seasat much higher latitudes,such as Eara which col- those that overspreadEurope, western Aus- rgressive-regres- tralia, 6.3.1 CyclesI andII and western South America. Although med Absaroka. there were remarkable parallels in the evolu- I outlines of the In the latestCambrian, Ordovician, and Silu- tionary developmentof low- and highlatitude roka cycle are rian history ofthe Conodonta,I recognizefive Ordovician faunas, already evident in the in- rr-Mississippian second-orderevolutionary cycles. These are terval of Cycle I, there was limited exchange qtich show a identified by Roman nurnerals I to V in Fig. betweentheir chamcteristicfaunas. Very pos- l5rlranian and a 6.1. sibly the existencethrough the Ordovician of , decline in the Cycle I, which began in the Late Cambrian well-developedconodonl faunas from the with the appearanceof the first conodontsin equatoralmost to the pole contributedto the i to interpret the the shallow low-latitudeseas of North Amer- exceptionallyhigh diversity ofthose faunas. Ite cratonic cy- ica, Australia,and China,is largelya recordof Cycle II is related, at least in North America {- record major the rapid diversification of the Teridontus lin- whereit is best known, to a short-livedtrans- 'etxrl uEunlIS ur uolpurlxe 01 -rE^pue slnual ..7,, s" qcns suxoJJo el?os 3Jo F-IO JJuUIUsdde ts3l?l peulpep sluopouocpu" 'lq8rTss",{r xeldutoi DpalnJD oulpopaH nle^-tr\o\eqs erp E ul PelEUIIulel lsorup ^l[s :alzerE B-rlPq3Iq eql -re^rp ur fta,{ocell spguopouolstp oql Iuo{ ruo{ lueurdola^ep s"a ecu"ogruErs 39 pue ppuopoqlsuSoql?ds 'sluauruoJr^uJ apnlllsf^\ol auu?ur-uJdo eJoul 'IA alt.{J Jo snqwuSosstto) lrotrs er{l uo{J sapnqpuSllod 5lcols pl[apoucl ur sJalEA{ redoep Jo euIll u?rcI opJO Jalel ur t JsEarJur ploJxls Jq ol eureJ q Jrlt 'snppun 'd pue snD : E-reds luopouoc eql rrjo+ asoJesttDpad qJlq,t Suunp uott IEJrd,(l -elouur aposldeue ,{q pe,to11o;se { qJIII { -r? 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.As indicatedin 6.3.4 Devonianand Carboruferowcycles lygnathusestablished in earlier phasesof the Fcies to be the cycle,and diversity droppedto 2l in the mid- hida which di- As noted in Section 6.2, Ziegler and I-ane Givetian low-diversity interval that initiated r ard dominates (1987) have recently recognizedsix second- Cycle VIII. A bit later in the Givetian (late order cycles in the evolutionary development Middle Devonian), iterative developmentof Llcle III is gen- of Devonian and Early Carboniferouscono- "Polygnathus" latifossatus from the spatho- fnction and is donts.These are identified in Fig. 6.2 as Cycles gnathodontid stock led rapidly to establish- mbined effects VI to XI. ment of Mesotaxis, Schmidtognathus,Klapper- hg of the world Cycle VI began with a short interval in the ina alnd,ultimately, Palmatolepis,which I have rr glaciation.Of late Silurian and earliest Devonian during set asidein Chapter 5 as the new family Pat- Esentedby spe- which the diversity of conodont species matolepidae.Species of these genera,which Es only 7 sur- droppedto a low of 6. This critical interval in were apparently adapted to the increasingly e gocks were all the history ofthe Conodontawas terminated in widespreadopen marine enyironmentsof the Qunas in low mid-Lochkoviantime by an innovative burst, late Middle Devonian, together with new he of the lin- effectedby vigorous speciation within Ozarko- forms developedfrom surviving membersof * (or colder- dina and iterctive deyelopmentfrom the spath- Ihe Polygnathus stock and short-liyed species ainued into the ognathodontid, icriodellid, and/or distom- of Ancyrodella that also evolved iteratively odontid stocksofa flood ofspeciesassigned to from spathognathodontidancestors, accounted Amydrotaxis, Ancyrodella, Pedavis, Pelel

YJNOCONO] AHJ 9EI EVOLUTIONARYPATTERNS 137 bthodontidae), ulations of idiognathodontid conodonts de- also provide in Fig. 6.3 a zone-by-zonelog of b Spathognath- scendedfrom highly variableGnathodus girtyi the ratio of origination to extinction of cono- nar-r/ eYents, gradually segregatedinto discreteand some- dont species.That log may be used (with the u. tt the Polyg- what lessvariable stocks identified as Decllno- customarycaveats) as a crude index to tem- misian high-di gnathodus, Idiognathoides, Neognathodus, poral oscillationsin eyolutionaryvigor. It more than 50 Idiognathodus,and' streptognarhodus. Radia- Although at least lg5 conodontsfecies orig- fted at a hUh tion ofthesestocks kept the evolutionaryindex inatedin the permian-Triassicinterval, speciis im by develop- above the maintenancelevel of 1.0 through diversity hoveredaround l0 at any one time, f earl;-'species of mostofthe Morrowanand promoteda slowre- droppingto a low of 5 in the earliestTriassic prioniodinide r coveryin species-leveldiversity, which peaked but reboundingrapidly in the sameinterval to lnl short-lived in the succeedingAtokan epochwith addition a post-Mississippianhigh of 22. ',futtrognathus, of the first representativesof Diplognathodus Fig. 6.3 also ouflines four second-ordercy- Staurognathus). and the Gondolellidaeand gradual phyletic cles in the permian and another four in the fr rhe conspic- evolutionofthe/ry'eognathodusltneage. Triassic. t the evolution- Extinction of Neognathodus and probably The earliest of the Permian cycles,Cycle also of Rhachistognathus in tl|'elate Desmoine- XIV in Fig. 6.3,followed a long interval in the te Visean and sian (Pennsylvanian)marked the end of Cycle late Pennsylvanianand Asselianwhen the evo- rfosippian) seg- XII, which is also shownin Fig. 6.2 to be ter- lutionary index was consistentlybelow 1.0 and corresponds in minated by a rapid declinein species-leveldi- was provoked by the appearancein the Sak- bse of Sloss's versity. Continuedgradual phyletic speciation marian of an early speciesof Neogondolella(N. t- The end of in the I d i og n at h o d us- S t r ep t og na t hodu s lineage, bisselli), the first speciesof Sweetognathus(5. imus declinein together with the appeaftnce of Aethotaxis, EI- merrilli), and a distinctive species of Drplo- Ie primarily to Iisonia, and new speciesof Gondolella, Diplo- gnathodus (D- sakmariensis). N. bisselli is ination in la1e gnathodus, and Hindeodus, signaled a brief in- thought to have evolved ftom N. praebisselli, ryhodus, Pseu- terval of innovation in the eady part of the which precedesit stratigraphically.However, El stocksas the mid-PennsylvanianMissourian Epoch and the thesetwo speciesare separatedby much ofthe lch they were somewhatlater peak in species-leveldiversity Pennsylvanian from N. clarki, the earliest spe- tea- However, that marked culmination of Cycle XIII. Note cies with elementsmorphologically assignable G a-ndincrease in Figs. 6.2 and 6.3 that in the latter half of to Neogondolella.For this reason,I suspectthat Erzed by much CycleXIII the evolutionaryindex was contin- the N. praebisselli-N.bisselli lineage is an in- rtle salinity and uouslybelow 1.0 and that speciesleveldiversity dependent Permian development from the q)porrumty to declinedgradually to 15in the Virgilian and to long-ranging Xaniogna.thus-Cypridodellastock ih and prion- l0 in the succeedingAssel.ian Stage ofthe Early which, as I speculatedin Section 5.8.5, was d and thereby Permian. Although speciesof Hindeodus, Di- probably the progenitor of several Gondolella rr1 in species- plognathodus, Streptognathodus, Idiognatho- lineagesin the Pennsylvanianand earliest lbdiversity in- dus, Adetognathus, Gondolella, and.E llisonia Permianand the ancestor,as well. ofnumerous ,lbgelgnathus, survivedthrough much or all ofthis long inter- additional lineages of Neogondolella, Neospa- erolved from val ofsorely restrictedevolutionary vigor, only thodus, and, Epigondolella later on in the tte innovative the Hindeodus, Diplognathodus, gondolellid, Triassic. iat a\d. Vogel- and Ellisonia lineagessurvived Clark's (1972) SecondaryCycle XV follows the early Artin- I this cycle,but Early Permian crisis to provide the basis for skianextinction of the typically Carboniferous lrir ed through secondarycycles in later Permianand Triassic genera Streptognathodus, I diognathodus, and hanian. seas. Adetognathus. Following a brief interval of pecies-leveldi- slightly lowered diversity, a short innovative ion of Cycle XI burst resulted in 6.3.5 Permianand Triassiccycles the appearanceof the earliest ment of Cayus- speciesof .ly'eostreptognathodus, Sweetina, and dinction in the Fig. 6.3 is a zone-by-zonesummary of con- Merrillina. Neostreptognathodus apparently dus. Lochriea, odont speciesdiversity through the Permian representsa modification of the Diplogndtho- os-el.er,during and Triassicperiods, which togetherrepresent dus-Sweetognalhusstock, whereasI have inter- dnian) interval 78 million yearsof geologictime. 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E of secondary I b to -Anisiande- nia and perhaps = z Ents elsewhere x l Chirodella and tu, 10 I l_r very tiny ele- \ im (or part o0 z \x I Xaniognathus- o tine, several frg- the type, M { \ dr debut. It is rdr ed from Scy- x\ hEd iteratively 'Hella stock. I \ rily- becauseno 400 75 i assembling a Enstates mor- Fig. 6.4. Survivorship curves(left figure)for cohortsofconodont genera(e.g., all generaoriginaling in Ordovician) rn Scythian and and curve oflongevity ofconodont generaofall ages(on right). Redrawn from Clark (1983). ts a high-diver- td to develop- (1983,1987) has recently focused particular at- the Phanerozoicmarine record." The data they EXaniognathus- tention on events in the late Paleozoicand present, however, like those for conodonts ige commonly eady Mesozoichistory ofthe phylum that pre- shown graphicallyin Fig. 6.5, show generally t perhaps better cededits extinctionat the end of the Triassic. high extinction intensities throughout the Late rdla. which was In his 1983study Clark presenteda seriesof Triassic,with a maximum in the latestNorian ) b!- Kiril Budu- survivorship curves (Fig. 6.4) for Cambrian (or Rhaetic).This suggeststo me, as it appar- I preceded the through Triassic cohorts of conodont genera ently did to Clark (1983),that the end-Triassic ; XD( was rein- and a summary curve for all conodont genera extinctionofconodonts may havebeen the cu- a development listed in the Treatise(Clark el al., t98l). Clark mulative result of severalfactors. not of a sin- 1udolurnishius- noted that these curves indicate that the ayer- gle catastrophicevent that terminatedthe phy- agesurvival of systemiccohorts was 109 my lum "well beforeits time." tde andthe last and that meansurvival ofconodont genera was Farly in the Permian,at the endofsecondary 1 beganin Kar- about 30 my. Thus, as Clark pointed out, an CycleXIII, a majority ofthe typically Carbon- t of Pseudofur- observerin the late Paleozoicwith accessto the iferous stocks disappeared,following a long inella group of same records would not have foreseenthe end- late Pennsylvanian and early Permian interval fdiversity epi- Triassic extinction of the phylum but would during which species-level diversity plum- ! siFaled by it- probably have predicted surviyal into at least metedand the evolutionaryindex was consis- laest Karnian the Jurassic and possibly into the Early tenfly below the maintenancelevel. Permian I of Epigondo- Cretaceous. recoyery was surely not spectacular.It primar- k- a replay of The record indicates that the Conodonta did ily involved a coupleofbursts of speciationby d rle only stock not survive into the Jurassic or Cretaceous, the gondolellid stem group, one eachby lhe EI- e Triassic. however, but that the phylum became extinct Iisonia and.the Diplognathodus stocks,but very in the latest Triassic. Conodonts were not the little action on the part of Hindeodus, which only groupto becomeextinct or to suffermajor merely "showed the flag" through most of the declinesin diyersity at this time. 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groupsof conodonts,particularly the Ozarko- gin iterative deyelopmentfrom basic lineages dinida and Prioniodinida.A similar patternis is also an attractive explanation.Plectodina apparent,however, in at leastsegments of the and.Phragmodus, for example, appearde novo Panderodontidaand Prioniodontida, and it in the early Middle Ordovician, and their spe- may be generalin the Conodontaas a whole. cies forrned skeletal apparatusesthat are, in a As shown diagrammaticallyin Fig. 5.36, nurnberof ways,closely similar to thosebuilt which summarizesmy viewson the phylogeny by severalspecies in the Multioistodontidae of the Ozarkodinida,elaboration of the sides (e.g.,Paraprioniodus costotus\. Because the lat- and surfacesofPa-element crowns was carried ter precedePhragmodus and,Pleclodina slrati- out repetitively in spathognathodontidpopu- graphically,they havebeen considered (by me, lationsat severalwidely spacedintervals in the among olhers) as attractiye candidatesfor Silurian and Deyonian.As a consequence,ap- ancestors. However, multioistodontid ele- paratusesofthe speciesthat developedin each mentsare mostly hyaline,and thereis little to oftheseiterative bursts are closelysimilar. For recommendthem in other morphologicpartic- example, Ancyrodelloides of the early Devo- ulars as hallmarks of the ancestorsof either nian has Pa and Pb elementsthat are very sim- Phragmodusor Plectodina. I now suspectthat ilar to those of early Silurian Pterospathodus those two lineagesdeveloped independently, and also essentiallyidentical in morphologyto and at slightlydiferent times,from generalized those of later Devonian Ancyrodella. The spe- prioniodontide ancestors in Tripodus (Oixo- cies of early Siltian Kockelella experimented dontidae).Although one may distinguishread- with elaborationof Pa elementsin much the ily betweenrnany of the elementsin appara- tc samemanner as did early DevonianEognath- tuses of Phragmodus and, Plectodina, others odus, pitnitive representatives of somewhat (includingcertain Pa elements)are closely sim- r smple number of younger Polygnathus, and, a number of later ilar. Thus homeomorphy rin eachzone, and may not be as great I d|Iough the Early Devonian and early Carboniferousspecies as- as between Ancyrodelloides and,Ancyrodella, lG plo$ per capita signedto Scaphignathus(Spathognathodonti- but it is nevenhelesssubstantial. dae)and the Cavusgnathidae.And iterativede- I suspectthat iteration alsocharacterized Si- velopment of the Protognathodus-Gnalhodus,lurian developmentofthe prioniodontidefam- Diplognathodus, Lochriea, and,Rhachistogna- ily Distomodontidae,but this may be very dif- Ea or four latest /lius lineages from B ispathodus (Spathognath- ficult to establishobjectively, and there are $le to adapt to odontidae)produced such a welter of species surely other possibilities,as indicated in Sec- rditions proba- with morphologicallysimilar Pa elementsthat tion 5.7.5.Ifthe basicapparatus pattern ofthe : Triassicby a supraspecificphylogenies are notoriouslydiffi- distomodontsincluded unplatformed pastinate l short, the phy- cult to reconstruct or defend. elementsin the P positions,then iterative de- It its adapative In Section5.6I havealso noted my suspicion velopmentmay have beenresponsible for in! 'ellisoniids were that Parabelodina denticulata, a panderodon- tiation of stockssuch as thoserepresented by rcmained-and tide specieswith well-developed rastrate ele- Icriodina, Hadrognathus and, ultimately, even d been more at ments in its skeletalapparatus (and thus simi- some or all of the icriodonts.Chatterton and plagic environ- lar to speciesof Belodina and,Pseudobelodina), Peny (1977)seem also to have suggestedthat Peolsylvanian. evolved directly from a conlemporaryspecies iteration might have been the active pattern in lonta may thus of Panderodus(P.bergstroem), not from some icriodont evolution when they wrote that d luck (beingin earlier speciesof Belodina or Pseudobelodina. rime) than of Other evidence,mostly unpublished,suggests speciesthat could be or have beenassigned to the genus c incapacity. that Panderodusitselfincludes a number oflin- Pelekysgnathus, as it is broadly conceived, may have eages,each probably deserving of independent been derived from other genera during four diferent generic(or even familial) designationand rep- evolutionary events(origin of"P." inder in the Late Si- lurian, origin of I hadnagyi in the Lochkovian, origin tts resenting chronologically distinct iterations of of lsteptotaxis'l Iumishi group in the Eady Devonian iirersity-related stocks characterized by skeletal elements of and. oigin of "P." comn r/rrs in the late Devonian. ;r-eFaltimes tied closelysimilar morphology. diversity cycles Within the Prioniodontida rhere are quite a The recent suggestionby Sandbergand Dree- uarious major number of"cryptogenic" stocksfor whoseori- sen(1984) that a groupof LateDevonian spe- 'uo uercr^oplo elppq l aql IIro.lJser3 Jo qppopttdt) ruo{ luerudols^ep ur p3^lo^ .snl -eds tuopouoc nd.eJe tnq Ip pezrropeJ?rlcpue -ur ueeq e^eq IJe,{l uoqeJolr Jot?.I u"rrhopJo eql rn [q $lcols leJo^asuI lue -er?dde elelquraru4lnru^Bul e pe\ D alopuosoaN -seJdore,tr sed^l luouele^lJEa lueJeJrp leqt ellloJdoc c$s?uJ ? rrlo{ ecuepr^eelrdsep -ror[ ue^es ro xrs qlr/r\ sosnleEdd?^fl"c€olorid pelHoq?lo .(D apopudtJ Jo) snqpuSotuox uI ,{flecrurou ,qlnd .{toloqdJour luoJoJrp ,tp?eJ8'Jetq lrq ? -ox?l ueppq eq ,(Ouaunc ,(eur sesnlH?dd? 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and Conodonti Is. respectively) cs in which ele- morphologically z Y€r]' soon in the lasses, however, @ ratus came to be = rs slightly, then, rphology. Fully (., ir or sevenmor- tsTes rperepres- r the Ordovician r conodont spe- irn on. lJp uo uo[eur pepnJcurs{cols epruIpo{Ezo lsoru '3lozoolDd 'se8?lqruessEFJnlEu ,(q peluosarder selJeds ; eI? gsrtolorq eql u! J4e[ pue usruo^ec eql uI 'eep Jatuno^ puE 'saroedsueunls pue u?rcr^opro PJo lo4uoc eql -rTlepourlpue'5"prluopourolsr(I'e?pouopo lsow pgzqereuru lou eJe,{Asuonrsod W D{IE.\JESqO JOII -qleuSoqleds eql ur stooJ glv{r serceds,tq suoq pu? S eqf uI stueuelo^ldrurs ',qlrqell"A? elsqdsoqd E-\ uo pepusd -rsodd ur pedoleAepeJe,r Euourele perluJllJo suourpuoJJepun 'snqJ 'suoulsod I SaJnpeJ IEIOI peuuoJl?Id^lpel?eder'uEunIrS oql uI 'suoursodesoql ur snlpndd" reqlo ur slueureleJo uoDcunJaql ol Fn ,{q 8urru4 perrrJoJsluorrJele poruJoJFld ora,$ (e?pql?uE (ocusuodur ouJo Jo)ecuelodur resselJosdeq lE lsrll sulellso -oceld,(lod 'eepqleuSolEg ''6 e) sst"eurl .e\eJe -Jedlnq slueureJed Jo uoBcuru eql ol acu?uod ftloJe ueg^\laq fpo ur lslueuralaru-roJrunf,ed peu oJpldun -IuI IssIluC Jo s?,{rUoB?zll?leullu leql S01?Fl l.iEu eroql 1?gr perdncco eJo^rsesqeJ?dd? polBnuereJrp ^q -sod oqucsqnsI qcr-q,'aol auo eql 'suolluu?Idxo 4oJd ol? ,{ue ue^eur suoursodd 'sruroJu?rcr^opJoJo ,quot ^llnJ elqrssod reqlo aJ? eJoqt lng 'se8"ls tlleu I qeFr?d,, 1?q1 -eur s uI suoursodd aql ur slueluglourJoJrurl -e8oluo relel ur poqJosal AII?nlc" ela,{{ suorl ruuoJ Jl8olorq -cedJo uorluoqsJa prB,rol s",$,tcuepuel Jof?ur -rsod esoql uI slueurale q3rqnaur Jo-/qrJnlsuj r| fu.a6t)PInoD ? sot"euq snorJ?Aur snleJ?dd?eql Jo luoul eroJeqp0s?0r slueruala ,^l pu? s Jo uoD?zrlB -dole^ep pu? uoDsrtuaJe:Urp,{J?uoqnlo^o uI -JOUTIuqCrqA UI SOrtOdSJO SelruA^nflUeSeJdOJ rdolo^ac ,'9 'suonrsodI" ul slueluelepozrleJeuru qlp\ caontsodd ut stuataaplo uouDnqDlg t 9 9 'satelqruess?^Eru I?rnl?u arn l"ql pelso8itnsueoq nuElar .lEururs seq 1I 'slueureleeloJtslp Jo suolltelloc pel?l ?6I) uossddet '/(uaSoluoJerlJ?g uI slueurele -nqel ruo{ peurrrJJeFpesoql puE 'sasnl?Jedde P d JI 'solcr!?d esoql ur parots alEqdsoqd eql se8glstlnp" ur IqeJe{s elelduroJ lueserdej AlqeumseJdqorq,{ tEB -ed?qs'ozrs Surqrosal,(q ro suon$od I I puE S ur sluelxole 'seBelqruass?IeJnleu ulo{ pelelnclsJ sorl I EEaq J^Eq Snql Jo uoqezrluJeururdn tur^6 sluauruoJruo -?J uuoJrurlred-uroJrrusJ eql uI &uBdslp pp JueuoEol,(qd Jood-eteqdsoqdol peldsp? e^?q^q ,{eur slueur -u4sqns e sr areqtlEql JlBcJPur 'ElJ uI F I l.'9 . truru"d qsruc -eled '^larrluaro '^lsAJ€JpetuasoJdoJ esoqJ 'serc00s lxrs ur palEredo 'punor?^q oE ol qEnouo oleqdsoqd szr\ oJoql eleurs Jo (ueSoluo oql ur set?ls e^rssgccns I tsqr sapnltuoc qcFI r ur slueuruoJrlue pelqequr o^?q furu Jo spJocerejnd /(F?euursleJ 01 ruees speq e^rs d;o uralsfsEur If JoJsuoddns :DJO Sluar ele 1186t) uoctN 'suonDpueue qll^r '(986I ) leoas uro{ u,r\Erped 03?Jslrurs Jo (sprs) s.SElquresseIelnl€u tuo.rJpo^uep 'eJu?cgru osoql uro{ lue$Jrp € (seurJpeqsEp oo) seEuonberJ lueuelo-eFJcsrp Jo slodeJ tuo{ pe^uop soleJ 'oslv sdno€ or(uouoxEl^luoruruoc IIE ur olun olrlBs eql l€ ecqd e)Igl lou plp sollEJ ur uoqcnpar oql pue suorlcolloc uEunl ns sEt\ uou?l -ls-lsod {uEur ur sluouelo ruloJnuer Jeqrunulno slueuole uroJrunJoal r(q^r .Igolc lou sr U sluopouoJ crs ) eq -i?ru ]r 'fuol -s?ul q8norql uerJr^oplo Jo sosnlErealdEul stueurele uuoJruuced puE ruroJlruEr uoe,{rlgqorler ur spuorJ 'r'9 'Eld D rE 1Jols rof?ru ro auos pezr r, nura ttlt rrs ouo lE I I | ^3o I I $ treJ eql uro+ \. I) IgIUoIUUOJI,.I. :Ioq?la,fueuoq ,;.. i i

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VINOCONOJ AHJ nnl EVOLUTIONARY PATTERNS 145

specieswith platformedpectiniform elements tial ecologic controls in the materials they in the Pa position.The Prioniodinidadelayed study. developmentof platformed P elementsuntil The large, stmtigraphicallywell-controlled the Mississippian,when the curious, short- collectionsayailable to studentsof conodonts lived Bactrognathidaeinvented thern. Later, should also be well suited to studiesof devel- however, in the Pennsylvanian(and increas- opmental, or evolutionary, strategy.Because ingly in the Permianand Triassic),prioniodi- well-madecollections commonly include ele- nide stocks came to be characterizedby plat- ments that represent various stagesin the on- formed pectiniform elements in the Pa togenetichistory ofthe speciesthat contributed position. to thosecollections, it shouldbe possibleto re- In the absenceof firm information as to the late ontogenetictiming ofthe morphologicfea- functionofelements in any positionin the con- tures recorded to developmenlal strategiesin odont apparatusit is diftcult to relateevolu- the lineagesthat formed them. And, if collec- tionary elaborationofP elementsto specificen- tions arecarefully related to the petrologicand vironmental or behavioral factors.However, other biologic properties of the rocks from ... from the fact that such elaborationcharacter- which they vvereobtained, it should also be ized someor all of the lineagesin nearlyevery possible,in time, to determinethe natureand major stockat onetime or anotherin their his- extent of any relationship betweendeyelop- im rtrrough Trias- tory, it may be concluded that platform elabo- mental strategy and environmental pa- many post-Si- ration was positive groups. surely of adaptive sig- rameters. nic- Also, from those nificance. Althoughinformation on the ontogeneticde- a.lions. (1987), -rent Nicoll who suggeststllat the skeletal velopment of various skeletal elementshas elementsofconodonts may havebeen internal been provided by various authors,I am not supports for ciliated tissue in the food-gather- awarethat anyonehas yet documentedstages ing systemof generallymicrophagous animals, in the ontogenyof a conodont speciesfrorn Ents in which concludesthat P elementswere opposedand studiesthat involve all elementsof the skelelal to go around. operatedin sucha fashionas to roll, bruise,and apparatus.Consequently, in the following sec- rirely, by P ele- crushparticulate matter caughtbetween them. tions I summarizepertinent information from phosphate-poor Phylogeneticelaboration of P elementsmight a few recentstudies ofPa elementsthat sugg€st ineralization of thus have beenrelated to changeswith time in that developmental strategies may have dif- 6 by resorbing size,shape, and bruise-or cmshabilityof food fered greatly from one group of conodonts to dored in those particles.If P elementsfunctioned as teeth,as the next. We can only guessat the extent to Jeppsson(1979, 1980)and othersconclude, a which additional strategiesmay be suggested similar relationshipmight alsobe postulated. by future studies of complete apparatuses. I P positions 6.7 DevelopmentalStsategies t ard develop- 6.7.1 Recapitulqtion irus lineagesa Gould (1977)has provided signal service to the Heterochrony involves "changesin the relative boration of pec- biologic community by emphasizingnot only time ofappearanceand rate ofdeyelopment for iions. In a ma- that "parallels between ontogeny and phylog- characters already present in ancestors" ritions in even eny are produced by heterochrony" but also (Gould, 1977)and may be effectedeirher by ac- , were occupied that theremay be a continuumofrelationships celerationor retardation.Ifa characterthat ap- ments; in only between ecologic factors and the life-history pears in the adult stageofan ancestorappears dae. Polyplaco- patterns that may result from alterations in the at a youngerstage in developmentofa descen- rments formed timing by which various somatic and beharr- dant, acceleration is the processinvolved and ian. platformed ioral features develop. In short, Gould ex- classicalrecapitulation the result. Ii on the rdl-v in P posi- pandedon Van Valen's(1973) somewhat ear- other hand, a character that appears in the E Spathognath- lier observation that eyolution might well be youngstage ofan ancestorappears in, or is re- .nd Icriodelli the control of development by ecology. Paleo- tainedinto, the adult stagesofa descendant,re- later in the biologists are thus encouraged to seek infor- tardation is the process and paedomorphosis locks included matioD on developmentalpattems and poten- the result. : E)UJTUV 'COS Jo 'a^q?Jelr q8nolql seqruniloddo peleJo ,(lpe uounlo^e eqt rlJJq.rur oueuecs peul0no -d Jo I T pe) r3o -leedeJ se8uallEqoorll Jol(su? ol $lcols-urels osp e^eq (t86I) quroCcl pu? peoqp?org" rrJ uI 'sluoPo Jo l pue '^uetoluo r -l 'leltrhl ol4elrasuoc snou?^Jo eqt ol (srs"q f ^lqrq" -f ) 'refintrl euo-roJ-euoe uo s,te^{lElou qSnoqlp) slue^e Jo se8?ls Jelel pu? ralq olur sJepsJerlc rt- -c 'reddsDl 3q"lsne rapro-pumes ol pol?lar uees elrue^nfJo uouueleJ eql-^uoloau Jo eTdrx? -t I,S C ')u?lc -Je^rpJe^al-seroeds puu JoErAdJ?uorlnlo^e ^1$ur -xe 'ssor8 ,{lJr?JIIIIS JI 'petueulncop Uo^l ,(Jq BI'ratseqJrqJ suou"nlcnu 'sdnoJSeseqlJo fuolsq -euoseeJ3 eq 01 sueos sql seprulpo{Jezo stuopo TeJrTc/b0Z Jo A P) luenbssqnseql uI 'sdnort crurouox?l Jofuru dnort xelduoc srqtJo.ftolsq oql uI elel 'selurl tI dd 'sree{ pe^lo^a D 11861)- Jo lueuqsrlqElse,(lr"e pu? snleJ?ddelBlelels Iere^os sd?qrod 'sttpoqtDuSorpJruo{ 99 'LS: luoalod eql Jo uoqeroqele (pld"r AITIBJpue) elqelou e^"q ot sJ?eddeszpoqtDuSofiaus rcrll pluesnp 'I Er) (I 5t&tc s3 \ eraql qcqndtuunp 'uonerp?Je^rtd"pe -oqtou&ofia4s llr.p? slueulele 3d eql Jo A3o '961 I"c Jo -rsselce Jo ler0 ol uJell?dur suuoJuocEluopo 1oqfuou ur luecsrurrreJsr l?ql f,lJee I tuelS:^\qUOU -uoC eql Jo p"erds pue luourdole^op purul (rr et"ls qtnor0 ssedsnpotllouSolpl ^ueSoluoJo sluelu I u"r^olr{Jo.J " (I g uoueneqJ -0I0ed eql1"q1pelou s"^\ lI 6'6 s uoqcesuI fr8ururns 8'9 -atl 'sI DlDlls 'seJnt?eJc€oloqtuou allue^nflrqlq I arll pu? ePpq -xe lnq '^lunl"u l?nxesl? ozrspuuou Jo ,{lleJe ! slsoqdJoruoP Alu 'I 'peeqp?org 'crsseul ete.l eql -uoEoJe llnsgJ sE'slEnpIAIPurcrualooN lf, " eql ro azlsur uoqerell" .as sltssotr ur srolseJu?p elopuo8 pezrlaeua8ejour Jo -nl"ur IpnxesJoSuuIID PUD eq i(eru seJqeeJ o Jo JJu"Jgru esortrtto o appuoSoaNJo suoqElndod ur Jeqlre tnoqll^\ 'peprEler Jo 'pe^elep qclt{,{r rrgEI3J fu"uortr D Dltstw Jo urtuo sql uI pu" snqstuntop r€oloqfuour Jo luaudoJe^epeql uI ssec 's 'urg4stuag ao'tual x -nasd rJJorJo anqsow Jo lueurdole^ep eqt ur -oJdcrqdJoruopeed ? sr'pueq reqlo oql saJrIaroJau pe^lo^ur uegq a^eq osl? ,(uoloeu l?ql olou -aad pnxes Jo luoue^alqcs Aur,,Aol I 'ure^ petEIaJ ur 'puv ^?ru'seloeds D appuo?dT loJ ,(llBer8^lunlerudola^ep lou op l?ql sc4suelc?#qc " o/al. tsEal le roJ uorteFldJatur s.JeqsotrAlpol? e[ue^nf ,{q poqsmtulsrp ar? slcedseJroqlo uI -lluslsqnsseq (€861)pr"qcro 'suorloelloce^rs lnq'eml"rrl Alpnxesoq ,(eu]sFnpl{Ipur ?rrls 'IeAel -uelxeaJoru lsq,reulos uo poseq',tpnls lueceJ 's$auaSoJd pedole ep e^eq ol pl€s '$lco1s IDnpoJd suoDrp eJorue uI '^ueloauqEnoJrll uoqrpuoc crqfuotu orqfuouopeed^q auos uI 'seAetsllnpE olur 14 -ieur suoq?ln -ope?d sql pe^erqc? e^?q ,{"ur pue set?ls suoruodoJdJo'^lrortdurs',48oloqfuotuJo seJnl lsssuJ 01gl eql c4auaBoluoJelel pus lalEl olur sJeloeJuqc-eeJelrue^nf ureloJ leql sluslu?fuoJo suJalsd 4 'errrlJePuEru elua^nf urcter (aep11e1opuop) o appuo? plueudolo^ep sezueF?JeqcsrsoqdJot[opeed I olur lllnq osoql sarcadsc$seul elrl ur?uec sl.uaru -rd!, Jo Jo stsoqdtot'uoqazd?'l'9 q leJlJ II" lz lou -ele eqt t?ql pezru8mer(0161) reqso^ "d rsPuJ aql eArA 'pe^Io^ur ueeq e^eq lou ,(uoloau 'peJeprs tltf eql ur etlln -uoc eJe seurJrqrssodosoql ^"III JI st&pad ot pet€l '/t 9 pu? st 9 sarJ BJuUxa eql lclp -oJ ,{Iuo eJ" teql se8eeurTuro+ 'sr l?ql ur pezu?urunseJE ',{luo slueuele ed Jo areq lou pFo^\ 'sruqnp^lluelslpDurpoJopunpY vrorJ o^ou ap ro 'snql po^lo^ur qc[l^\ 'saruetol^qdosoql (186T^pnts'lE qprus q8noqllv -ou8sblalad tuo+ ssruq lare^es pe^lo^o e^"q te {ftlJ ur) relSorz pue surl}IJ KqsrdaloloulDd 6 [[Er!SJO SuOq AevJsnpou)I |egt lse8Snssuo4?Jeprsuoc reqlo roJ patculsuoceJeuo eql uI pu? (6161) ralA 'serJeds d e '9 t'S uoqcosw pelecrpursV'suonrsod snl?J"d -erz pue e8rppe^\puE (tr6l) aSrppe^\ peurl 'JrssPuI^roJ r+B aql -d€ raqlo ur slueuralaqsmEuqslp lEql socueJeJ-lfro snqpuStlod Jo ,(uo8ol,{r{deql ur ecuopr^o^q ql ruo{ pes€erc Jrp IsrlueFqns eql p ceFeu puP-snpouJl pue ur aJ? soldruDxol€uoqlppv 'Jeuel eql Hrf ,{lreg oql s^DpadJo sllJelJJ.elo?d eqlJo sJeFBJeqcol uoq JO ^lurEldSeuOpe^\oJ-aeJql eql 01 lelrurrs esr^ueqlo -arull ,h Jo spou -ueI? fueulud e^et qruoJJl l pue peeqp?oJg slueuele d peurroJl?ldot el3uuepqlnoJ l Jro Jo l3 'eJuapr^ee^rlrefqo pouoddns puE ^ior po^lo^uurrr.r ^loleq I?c6oI e Jo reuuoJ eql uortppe pu? ird ',r\.ol sP^\ ar" et?lnlsod,{eql ocuonbes ^q dl?uo4nlo^o eql ur 'd \norJ snuuasuD^qsnpo8td Jo uorlnlo/re l"ql q 'uo uEru? I,{S sdelselrq^|slueurele d uo JndspJelel JoualuE u.{rou)lIIea srlr 'aldur€xeroC suorl?Fdod ^{ou ft€ Flelols rreql 0I Jo ',{uoloou qAnojqt 'ssol crqdJourop snor^eJd,tll"Jrqd?rtuprtsJo Imrd,q stuellIele |F qll-,t|{crqdrour -e?d ,{q pet?crpu eq (aeplllepolrrl 'epll ..oluo Pepp?,,ueeq e^eq 01 uoes t"ql sernleeJ sa8eaull pa,rq -uoporuoud)s?,lrprd ruo{ ^"III (oep4uopoucl'eprl crSoJoqtuouruo posncoJe^"q sJolleurtueuoBnl ralp 'e^rl4edeJ -uoporuoud)snpouJJ Jo salp?tueseJdeJi(F"a -o^oJeprsuoc 1"q1 sluopouorJo serPnls lsol/li

V.LNOCONOJ !IHJ 9br EVOLUTIONARY PATTERNS t47

E fPrioniodon- repetitive, development of generally short- Gould, S. J. (1977).Ontogeny and Phylogeny-The ir (Prioniodon- lived lineages that were strongly homeo- BelkDap Press of Harvard Univ. Press,Cam- l:ted by pae- morphic with their predecessorsin features of bridgeand tondon, 501pp. Jeppsson, (19'19). Dren!, of the their skeletalapparatuses. From the l-atePenn- L. Conodont element function. Lethqia 12, 153-l'll. ar While steps sylvanian on, however, speciesJeveldiversity - (1980). Function of the conodont ele- |P Postulateare was low, and populationsappear to have been rnents. Lahaia 13, 228. ttive evidence, at or below the maintenancelevel for long pe- Johnson,J. G., Klapper, G., and Sandberg,C. A. I Inmary anen- riods of time. With only a brief interruption in (1985).Devonian eustalic fluctuationsin Eura- gts of Pedavis the Early Triassic, extinction intensity meica. Bull. Geol.Soc. Am.96,567-587. in- Lipps. ( sbfiantial dif- J. l98l ). What. if anlthing. is micropa- creasedfrom the Early Permian to the end of leo\toloqy? Paleobiol. 7(2\, 167-199. G ln other ap- the Triassic,when the phylum wasreduced to Merrill, G. K., and Powell, R. J. (1980). Paleo- i Section5.7.6, a few species,probably representedby popula- biology of juvenile (nepionic?)conodonts from a. Icriodus may tions of small sizeand provincial distribution. the Drum Limestone(Pennsylvanian, Missour- m Pelekysgna- Although studiesof generic-levelsurvivorship ian-Kansas City area) and its bearing on apparatus ontogeny. J. Pqleont. 54, 1059- dubius, would not have led Permian observersto pre- L0'74. 4--dina distantly re- dict the extinction of conodontsbefore some Mosher, L. C. (1970). New conodont speciesas Elities are con- time in the Jurassic,the phylum did not sur- Triassicguide fossils.J. Paleont. 44,'137-742. bern involved. vive the Triassic.Reasons for extinction are Nicoll, R. S. (1987).Form and function ofthe Pa lat the Pa ele- not at all clearbut may haveincluded not element in the conodont animal. Po. 78-90 in only Palaeobiology (ed. speciesof Epr- of Conodonts R. J-.Aldridge). thosebuilt into the long post-Iate Pennsylva- Ellis Horwood, Chichester,180 pp. :rain juvenile nian decline,but also a dollop of bad luck in Orchard, M. J. (1983). Epigondolella popllations Er ontogenetic the Late Triassic when surviving basinal pop- and their phylogenyand zonation in the Upper d this paedo- ulationsmay havebeen unable to adaptto con- Triassic.Fossl/s and Strata 15, l'77-192. h-v. In a more ditions producedby a worldwide Sandberg,C. A., and Dreesen,R. (1984).Late De- drop in sea vonian icriodontid El more exten- biofacies models and alter- leYel. nate shallow-water conodont zonation. Geol I has substanti- Soc.Am. Spec.Paper 196, 143-178. irr at least two Sepkoski,J. J., Jr., and Raup, D. M. (1986). Pe- r relatedvein, I riodicity in marine extinction events.Pp. 3-36 e been involved References in Dynamics of Extinction (ed. D. K. Ellion). Wiley, New York, 294 pp. dh from Pseu- Bergstritm, S. M. (1983). Biogeography,evolu- Sloss,L. L. (1963). Sequencesin the uatonic in- t of Misikella tionary relationships, and biostratigraphic sig- terior of Nonh Ameica. Bull. Geol. Soc. Am. fulel Ia or those nificance of Ordovician platform conodonts. 74(2),93-t14. il ancestorsin Fossilsand Strata 15, 35-58. Sweet, W. C. (1970). Uppermost Permian and Broadhead,T. W. and McComb, R. (1983).Pae- Lower Triassicconodonts ofth€ Salt Ranseand domorphosisin the conodont family lcriodon- Trans-lndus ranges.west Pakjstan. Ppi 207- tidae and the evolutiolJ of lcriodus. Fossils and 275 h Stratigrephic boundary problems, Perm- Strq.ta15, 149-154. ian and Triassic of llest Pakislqn (ed. B. K.um- Chattenon, B. D. 8., and Perry, D. G. (1977). mel and C. Teichert). Univ. Kansas, Dept. Lochkovian d of the Con- trilobites and conodonts from Geol., Spec.Publ. 4. northwestern Canada. I Paleont. 51, 7'72- (1985).Conodonts: Those fascinating little lhat of a classi- - 796. whatzits."L Paleont. 59(3),485-494. rhich therewas (1983). Clark, D. L. Extinction of conodonts."/. Vail, P. R., Mitchum, R. M., Jr., and Thompson, loration of the Paleont.:57 , 652-661. S. III (1977). Seismic stratigraphy and global dablishment of - (1987).Conodonts: The final fifty million changesof sea level, pt. 4: Global cycles of years. Pp. 165-114 the subsequent Palaeobiology of Con- relative changesofsea level. Pp. 83-95 in,Sed- odonts (ed. R. J. Aldridge). Ellis Horwood, mic Stratigraphy-Applications to Hydrccar- i:al fluctuations Chichester,180 pp. bon Exploration (ed..C. E. Payton). Am. Assoc. des-level diver- Clark, D. L., Sweet, W. C., Bergstriim, S. M., Petrol. Geol.. Mem. 26. Mer eustatic Klapper, G., Austin, R. L., Rhodes, F. H. T., Van Valen, L. (1973). Festschrift. Science 180, t a one-for-one Miiller, K. 1., Zieg)er, W., Lirdstrijm, M., 488. Miller, F., (19E1). ts conserYatlve J. and Harris, A. G. Con- Walliser, O. H. (1983). Geologic processesand odonta. In Treotise on Invertebrate Paleontol- g.lobalevents. Terra Cognita 4,l'l-20. @es of repeat- of? (ed. R. A. Robison). Pt. W, Suppl. 2. Geol. - (1984).Pleading for a natural D/C-Bound- rgh iterative,or Soc.America and Univ. Kansas,202 pp. ary. Pp. 241-246 it The Devonian-Carbonifer- uD 'rrou4ertuel rqrp ol lcofqns lELrUap UOrl?UI rqsrrqeq'suq?q ru sSJuerJn3Jo I rl;)ql Jo soJnl F'rrE Jsols ,fie^ EOJ JSnPmg qJE sEqs?un?J lqe-6oaSolqoel p€p3Ju uorl?ur ! paurnno 0^"q p ruJudole^ep fuer [r\ou)[ eql r ilarqdzrEoet rfl pel?lnurrls FoqdeJxo ole Esteq dre^oJ I - illEcrlEuets,{s I puq iurouoxEl DJ Jo ',{B^\ InJ FOJ SIUOPOUOC D Jql rsqlreN llrsrp o^\1 peuq tu ur sluopouoS rlJ aqlr^\ pue r pse secur,rord flnoJ lueJe:urp p ruaudole^ep 856l ur 'orour rzoelad urqlr^\ rql sJolJEJcrSol rqlrrsrp JrqdEJB r f,raql 'sr l?qJ {r a{rl pe^?qeq E3aq ,tlpnp"J8 erou ,pu? eroul p w epft\plJo^{ rsou 1€ql puB IJnJJO Jreql UI Isqr pleq ,{ll?re rsr": t ,{uEurlog

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VJNOCONOC:IHJ Irl r conodont geD- aDl- d Pq.laeont.

9t-). Cycles in 7. PALEOECOLOGYANDPALEOBIOGEOGRAPHY Eian to mid- blaeobiolog of Ellis Horwood,

7.1 Introduction understood as a preamble to the following dis- cussion.Obviously, until we have For many yearsafter their discoveryit wasgen- satisfiedour curiosity and reachedsome agreement erally held that conodontswere cosmopolilan as to thesematters, conodonts will be less in in their occurrence within the marine realm useful reconstructingconditions in past depositional and that most specieswould turn out to be environmentsthan are featuresof the rocks worldwide in their distribution. However. as formed in thoseenvironments in interpreting more and nore information was assembled,it the conodonts.Thus I approacha gadually became clear that conodont species discussionof conodontecology cautiously, urith behavedlike the speciesof most otheranimals. initial em- phasis on featureson which there is general That is, there were lateral limits to their geo- agreement. graphicdistribution and decided,ifbroad, eco- logic factors that determined where they lived within Paleozoic and Triassic seas. Further- ?.2 Modeof Life. or Habil of Conodonts more, in 1958 Huckriede suggestedthat the developmentof Triassic conodontsfollowed It is common knowledge that elements repre- different courses in various biogeographic sentingthe same or closely similar conodont provinces,and in 1959Sweet, Turco, Wamer, species may be collected from sedimentary and Wilkie concluded that the distribution of rocks that represent a wide variety of deposi conodontsin rocksoflate Ordovicianage out- tional environments.In addition, many con- lined two distinct faunal provinces. odont specieshave beenshown to have had a Neither the ecology nor the biogeographyof very broad geographicdistribution, and a few conodontscould be studiedin a very meaning- may have beencosmopolitan. Those facts, to- ful way, of course,until a biologicallysound gether with the elongate, wormlike body and taxonomy had been developedand fleshedout distinctively finned tail of the few complete systematically. Nevertheless,the repeated dis- specimensknown, support the generallyheld covery between 1926 and 1966 that conodonts conclusionthat the animalswere probably nek- are exceptionally useful biostratigaphically tic in habit and that the distribution of most stimulated the assembly of comprehensive, speciesmay have beenlargely independent of geographicallywidespread collections through conditionson the bottom. Suchan interpreta- the known range of the group. Thus, with the tion seemsto be supported most strongly by developmentof the multielementtaxonomy I the common occurrence of conodonts in cer- haveoutlined in Chapter5, much of the infor- tain typesof black shalesthat yield fossilsonly mation neededfor both paleoecologicand pa- ofpelagic organismsbecause they accumulated leobiogeogaphic interpretation of conodont under anoxic bottom conditions that inhibited faunashas fallen into place. developmentofa benthicfauna. Becauseconodonts are extinct and have no Conodonts occur in rocks with corals, brach- very closeanalogs in the living biosphere,fea- iopods,echinoderms, and cephalopods,whose tures of their biologic associationsand lithic living representativesare all marine, but they occurrencesmust be usedto reconstructtheir havenot beenreported as autochthonous com- habits, habitats and ecologicpreferences. Infor- ponents of rocks known to have accumulated mation derived in such indirect ways is always in nonrnarineenvironments. Thus, as at leasta subject to debate, revision, and periodic rein- first approximation, conodonts may be inter- terpretation, of course,and this must be firmly pretedas pelagic,probably nektic, marine ani-

149 F UOUECgTIADS -nqulsrD leJolelJreql uI seumuuuocsrpruo{ sql 10usr srql lng'sstqquress?IErnl"u u 10u)1 'sqlsuEol 4J5 Y sluopouoc Jo eJfl Jo epour lo lrq?q aql uleld ul Jncco faql se suoDlodoJd eIIIes oql lnoqe ur sle^el tes Jql -xaol sldluell?'pueqrorllo oql uo '(516I) sne?r ur sluoruelopunfsrp Jo suoucellor uI tncro ) tueJa:urp'seru4 -q""c pu? setlj"g Jo lepolu uo4?toJaoslelelq pFoqs snpowDuSofia4s Jo snl?J"dd" aql Jo es pueuoppss oql 'uonnqulsrpl?Jel?l Jraql ur seFrnu4uocsrp slueuoduoc1?q1 padxe ol elqeuos?aroq pFo^\ UOrleEeJ ,(Z56I) EOf JO SurlzzndroJ uort"u?ldxe u" epr^ordol peldruet lr uoqt ssporlu srouIII Jo u?ru?^l[s EsrEEeJo crt?led -le pu" c6?lad era,r sluopouor l?ql uo4duns -uued oql uro{ pequcsep^q se8Elqulesse prnl?u Fu auo s" 'uou -seoql qll^l ueEoq1ee,{rs pu? uoppes It6I eqr ur pe^lesaJdseuo aql a)[I snl?redd?pla lEn ssel Jo erou ur peulllno 'lepolu uorl?cgrla$-qldep^q eql 1e4se wq snpoqlDltSoldaJts'pDuopoqlsuSorpr Ea-des .{ll"relel '$ICOJeUUErIl CrSS?UJ prr? 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YJ-NOCONOJ IIHJ 0sr PALEOECOLOGYAND PALEOBIOGEOGRAPHY bn from various rd fiom different med Pa elements ts the elements ir the skeletalap- bat this disjunct, ++++++++++ badsto the com- +++++++++++ n over-represen- ++++++++++ -a------O- - -ar- --af m late Paleozoic a rD a rD r.) skeletal appara- -- - 'a 'a mt speciesmay Aom one onto- tbat such differ- : from a pelagic retic stagesto a Fig.7.1. Schematicexplanation ofthe depth-stratificationmodel ofseddon and Sweet(1971). Diagram showstwo rin later ones. species;one indicated by crossesis uniformly distributed in a surficialwater stratum;the other, indicated by filled b some or all of ellipses,is uniformly distributed in a deepe!-wa1erstratum. Elementsofboth sp€cieswould accumulatelogether on mode of life, it the seafloor,butbetween A andB thoseofthe "cross" specieswould dominate,whereas between B and C the reverse E would be tlue. Redr-awn,with omissions,from Seddonand Sweet(1971). d study to deter- ries represented cttobenthic nib- more at home in tion in sedimentaryrocks. To Bamesand Fah- Figure 7.1 considersjust two pelagiccon- ove the deposi- raeus,the existenceof laterallysegregated bio- odont species,one representedby crosses,the rYe had diferent facies was taken to indicate that most other by filled ellipses.The crossspecies is as- r itr their life his- conodontswere benthic or nektobenthicorgan- sumed to have been widely and uniformly dis- tbs€rvation that, isms, whereasSeddon and Sweetfound that tributed in a stratum nearer to the surfacethan le water column laterally segregatedbiofacies (which are real) the ellipse species,which was also uniformly tauon, rn a near- required a special explanation if conodonts distributed, but was confined in its lifetime to iphering the life were pelagic. Although the two models seem a deeper-u,aterlayer. As individuals of each of qreciesbecomes very different-and they certainly began with thesespecies died, their heavy,phosphatic skel- hl it is a game very diferent premises-neither has been gen- etal remains would haye settled to the bottom. lattention to the erally acceptedor rejected.They both bear We would expect to find fossil representatives of conodontsto summarydiscussion before we go on to more of the crossspecies everywhere on the bottom. sitional basinas concrete matters. However, skeletalelements of the ellipsespe- I arrangement of cies would accumulateonly seawardof the mts. level at which the top of its depth zone 7. 3 . 1 The depth-strattficationmodel "dragged bottom." Consequently, there might Seddonand Sweet(1971) pointed out that the have been a tract of the bottom to the left of Ordovician and Devonian conodonts they point A in Fig. 7.1 on which no specimensof heses,have been were studying in eastem North America and the ellipsespecies came to restand in which the rlbution of con- Australia, respectively, characterized distinct, fossil record was exclusively of the cross spe- dc marine rocks. laterally segregatedbiofacies instead of being cies.On the other hand, the ellipsespecies, a bl, outlined in more or less uniform in their lateral distribu- relativelyrare componentof colleclionsmade tan with the as- tion, as one might expect the remains of truly from tlre rocksthat accumulatedbeneath point e pelagic and at- pelagicorganisms to be. To explainlateral seg- A, would pradually increase in abundance tion for puzzling regation of conodontsin the benthic record, relative to the cross sp€ciesin samples taken iistribution. The Seddon and Sv,/eetproposed that, in their life- fron rocks that were formed at greater and brnes and Fih- times, different conodonts inhabited diferent geater depth. At point B in Fig. 7.1, for ex- I, attempts to ex- levels in the sea,in the manner of living chae- ample, the two speciesmight be representedby iF of conodonts tognaths.A schematicillustration ofthe depth- approximately equal numbers of specimensl lateral distribu- stratificationmodel is given in Fig. 7.l. farther to the right, at point C, specim€nsof the 'ErC) I gsuurJurJ oql eql (Z', euerpuJpu" 'oqo ',(Irnluo) ur -olleu Jo crqlueqare^\ sputru€ osaglJo lsou r :{ppln eqJ uolSellq"uurcurJ eqlJo souolssru{pue sepqs 'souqeJll reql Euunp t?ql uBeur ol sluopo 'qErcr^opJo u"rcr^opro reddn pue elppu l snoJeJllrssoJ-uoc Jo uorlnqulslp pel?8e$es fllEletel aql r srql peJaAos srll ur luEpunqe elB sluopouoJ pelertuolu e^eq (516l) snasrq?Cpu? seureg rn sluopouoc ^fl?uonderxe F uodaY ppour uorJoS Saslonrol aqJ ,{?ur Z f l atEq 1?q1 ttDuuout)lo l8opJaoaladuDnaop.to I f l rI? suorlezrlBre E \Salaque^eN '61.61lnun poqsrtqndlou 'sdrqsuoq"leJ I SIUJIUUOJT,\Ua to seueql lnq €/61 ul u011u^{se,{ lEro sluopouoJuBrsr^ r auros 3J3 eJeql uouuros fue 1se33nsuoql ur poqceeJsuorsnls -opro uor8eu u"uuDurC uo uodoj ? ur pe/(ol I qJoJ u?rcr^op -um oql J! euruJelepol serpnlsluecal lela^os 1oJ I leporu uorlecgrle4s-q1depoql Jo uors he sl uorl€ruJoJ ezueuruns I luopouoc lnoqE suoll -Jo B ur pel"rofuocur sua eJnlBaJJ?lrIII$ ? pu" "(EoloJe Fp JlqErePrsuos -ezrpreuot el?ur ot 8u4drlIau? oroJaq 'snql 'suoneFdod psgrlz:1s-q1dappre^es Jo qcEa 'seldrcuud 4ursrp srqdef qcns ll\e+ ol elqrssod oq fllEnl ur eJoqsgopes?eJcep e^"q lqtur sonrsuopl?ql FE 'ilPrrurouo -ue^e 1rqorq^{ ruo{ serpntstuE8eleJo Jeq pooqIoIII eql pazru8ocor(€16I) ecnlq 'sued ^?ul ES:Jdar Serceds -urnu sopnlcureJuelalll oql.'Jo^e,{oH 'dnol8 eJoqsiuoerou slr ur Jeqlou? aloqsJ?su " 'uorUod E sE Sluopouos ol poldde eq ,{leJes l?ql slr ur ouo 'Je^EJrol",{r orueseql perdntco e^eq suorlezrlsJouet c€oloca la^ s" elB^eul oJoqJ sebeds elqrssodsr ^reJ lqtru lueJe:Urpleql lI 'uoq prdEPV uo6oU -IpP?q 'ulunloc rel?Arpag4erls sql ur sle el ! ,tSolorgluopouoJ Jo salpnts papales t't tEiis 8?s uI s^{o!€ lue3"fpe peldncco{eql qEnoqt ue^e ,uo oq a pue S ,0c "0t Jo eq1uo :aqletol poleFurnccEe^er{ + 3es deoP tou lqtur a4r'a!q.$) g:rnporlul s?^a 'slc?Jl?uoqnqulsp sesdlTlepu? sessoJc'lueruuor^uo 'pur8Jeur E .{F ur l5ell eleN eql qll4i sproJJEl$q lpqr uonelaJdJelureJrt ro 'eroqsJeeu? ol palculsoJs?^\ seroeds ler{l Eunlrs 'z'l 3!J JI -lo-eporx aql uolqord qree Jo uoqnlos oql ur ro 'oJoqsJoreqpeJ ueql e:oqsaq1 reau releerS esnot pue crqtueqoDlauJo 'rqlueq'crt?led s?,r{I', '8rCur sercadsssoJ3 eql ,Orsuepuorl " Jo erea\stuopouoc l"ql uoBou cDslldlurs,(lqEqord -Blndodeql Jr 'eldluExaroC 'sedolorqtuecefp? aql uopu€qEot sr szuruelrp aseqlol uounlos uo^e ur pelqnrunccst?q1 serc-?Jorq aql AulleduJoc uV'aJrl lpulruEorrllueq ueerqgq^lesolo pes"aJcur eq lq8ru slsEJluoo'pouguoc ol eJr$oq ueeq^FurseeJcur a^?q plno^{ l?ql suorlrpuos eJea qcr-q,'ir01 JoAEIrale,'(' eqt lnoqEnor{l uolloq clxou?repun pelDlnluncc? petnqulsrp^eql lou eJea tnq ecuelsHe qcrqr\ 'sepqs lc?lq cB?qdsoqdur sreqlo^lq"urn$Jd pogq?Jls-qldap^IuoJrun pel sluopouooJr 're^o,,tloH ^u"rrI " JO eououncco uolxruos orD pue sercgds leporrJ uorl Jo uo4.nqulsP u"lqodorusor flpuuesse^ueru aql -ecurlE4s-qtdapeqt Jo srolcDJlep JEteJ ^\?U uEldxe ol llnclglp Ilrls sr lr 'le^e,tloH 'soqlueq E se pegnuepr u00q seq suuoJ lete.r-Jodeep^q lueJte^ eql Jo slueuoduoo oJg^r Jo crqlueq ,(q peleururop seldu?s ur 'eJ?l ,Go eJ? Jo -oDlou eJe/t\ slErurue oql 3r pegldrurs ;(1tse,r 'pelueseJdoJlou AllErcuatoJe sluopouoc Jel?.r JJeUOUnqulslp luopouoc Jo suouEleJfuJlul -^\oll?qstpqt tc J eql pu? 'eseceqt tou .{[ple 'aJrlJo epou -ue8sr slql lsrll s,roqsecueuedxg ,na3 e ,{po ur cqluoqolleu Jo rrqluaq e Jo JooJdse uel4 aq pepedxeeq pFo^i sle^ollsedoep oql 01pelculs i(€.r ou ur ueo stuopouocJo pJocejpol?Seltos -er eJe^\ 1?q1 asoql s?3Joq,'(\'eldures fue^e eretElaql'u^\oqs e,\Eq(8t61) rlcl"eg pue uI pelueseJdaleq plnoqs aceJlnsaql lsaJEau ^ JeddEI)I s? 'q8noqtl? padd" 1"ert sEq tr 'qcns Je^eI erll pellqequl leql stuopouo3 'sr leql sV slrsodepfuEtueurpos ur sluopouocJououn 'sells pJ?.r\?eseJour ,(Ie^rsseJtoJduo{ ue)pl -qrrlsrpeqtJo uolaeJdJelul u? ot aldrcuud selduJesozuel'J?lEqo plnoqs,{lrsJe rp ur es?ejc -crldrurseqlJo uoqecrldd?u? ,{Ierarusr 'pauuol^lr -ur pnpzrS e'1 4 Ergul paqdul sr se urloJrun ueeqseg srseqlodi(q srql se lepour uorleter8es s" f ?u6uo se^{ urunloc Jel",r eql ur sIo eI -lpJJl?leql 'slueurJlJruloJruoJ Jo posodtuoJ snoue^ le sluopouoJJo uorlnqrrrslpeqt JI sesnl"$ddE I?lolols pue 'ecuepuedepursarc 'tu?JB?Ip -?Joqll pquesse'uounqulsp cu{dEJSoeBopr^\ eql,tq pelueserdarEaJe eql lnoqAnolql pelnqul fie^ e ,{q pezueD?rEqcII" 'crtpled s? peleld -uoc eJeA{sueujrcods ssolc Jo sJequnu pnba -relur eJea{sarJeds ? fluo 'tlq?q ur cqtueq qanoqt ue^e 'lusulluop aq tqtur sorcodsosdl[o ^loJ VJNOCONO] EHJ a9I PALEOECOLOCYAND PALEOBIOGEOCRAPHY 153

Fcies wereinter- rrized by a very csseDtiallithofa- dal apparatuses Its. The lateral- nhesis has been n of the simplic- J-f -:- 7--!------: =- m of the distrib- ra4 deposits.As r- f---t---t--,1_ i - \ rgh- as Klapper rn- the laterally t car in no way : or nektobenthic t disfibution are lals were nekto- Ldno I of the vagrant -;'"'t lhculr to explain ?-- ocs::: distribution of -';:,--:-*=!! t:::::::: ::;: m occurrenceof .-_-i-_---i__ - ____10cs rt shales,which r{ 4--... rr anoxicbottom beeD hostile to tinglJ compelling ; to abandonthe t conodontswere cnthicand to use m the mode-of- Fig. 7,2, Situation ofthe Cincinnati Region in the Middle and I-ate Ordovician. The Cincinnati RegioDis th€ tri- Ecords with the statetract in the centerofthe map. In general,it was part ofa broad carbonateshelfto which terngenousmaterial was introduced from the southeast and that was bordered on the norlhwest by the distal extremity of a narow, deep sag(white) that permitted connectionwilh cold, phosphate-richwaters to the south. Approximale positions of l0'and 20'S paleolatitudesindicated by heavy lines; Iight arrows suggestprevailing-wind direction; hea\rier arrows in sag suggestwind-driven circulation pattem permitting upwelling of phosphate-rich water in Cincinnati rt Ecology Region.Adapted from Crcssman(1973). c generalizations I conodonts as a :ilcludes a num- speciesrepresented are quite well known tax- tonic platform that was situated a few to as rich it tnay even- onomically, and their stratigraphic and geo- many as 20 degreessouth of the Ordovician srch principles. graphic distribution has been worked out in equator. Lithofacies are various mixtures of nake generaliza- considerabledetail. Somewhat less detailed in- shalederived from orogenicsources far to the X-- I sumrnarize formation is availableon the petrologyof Or- east and highly fossiliferouscarbonate rocks nine if the con- dovician rocks in the Cincinnati Region,and generatedon the spot, primarily from skeletal Est any common thereare some unanswered questions about the matter furnished by echinoderms, brachio- environments in which they accumulated. pods, and bryozoans and reworked and frag- Nevertheless,enough is known to supportgen- mented in some environmentsby wave- or eralizationsabout at least some of the factors storm-generatedcurrents. Fossils in mostofthe of Cincinnati that may have controlled distribution of the carbonaterocks haye been transported,but conodontsin the warm, low-latitudeseas that probably not too far frorn their living sites. abundant in the covered this area in the Middle and Late The conceptually straightforward deposi tEr OrdoYician Ordovician. tional frameworkofthe CincinnatiRegion was lncinnati Region The Middle and Upper Ordovicianrocks of complicatedby differential uplift and subsi- ia (Fig. 7.2). The the Cincinnati Region accumulatedon a cra- denceof segmentsof the platform along pre- orIJ F:do) sluopouosaql Jo sruJelut J?lrutrs3J? qcrq,Yrueql aroIAIq8q sr pu"'sluopouocJo ers^r TOrSOdap 'sercq Jo sdnoJ8 JofEul o1A1eJE uorl?uroC slol suGluooEuESol ^lrsra^rpoql 'qldop uoq?suedruoc irag s^?IJ .trd IEE se{?r(I prl? reqruer^l eql ,{q € , ur aql 'tueuuolr^ue clqorc?s,(p gaIE "u?Eo-J JaL\OII?qS pelreru seluojlxe cuFlu,{qlpq eqt uae^Ueg 'FInb^roleq ,{IIeJeueA ^lqeqoJd ur pelrsodop sB^r salEl srcR?uuoJ lue 's3ldru?spol?losr ur -nrsod(€/6I) uErrssarJ" gcrq,,tl'opqs elrssU qsr tue^ eql ! -ilEqs 0Jeq1pu" oJeqdn ulnl ,(er[ uolEou nsuurcurJ -u^\oJqPUE ellllrsrJleJ snoJeJllollJd'qslu^rolq Ssrlrl u?rcr^ E eql Jo u"rcr^opro reddn eql uro{J rr.rou)l sel, 'pappeqJelu sr eu?eo.Jeql 'uou?uuoC soIeJC r lquel Jeuc I -eds,(ue $orxl? Jo suerurcadseFurs qtnoqtle (u?Ipuouqcru) u?rcr^opJo ole-I oql sr puo ,'Aol alpprn aql ur o 'seIeJOeql ur,t\ol tue^ Alrst'^re snpofiO 1?qs eql lV 'euolserr.Irl uoltulxs-I ueror^opJo l suLL (Z '3!C I pue snqpuSopqdv Jo sercedslueseJdeJ JI?q eIpprI^I ,{UsoIII eql Jo requJel I Eup8o-I eqt sr r4nos 'etsEuole Jeqlo eqt seereq1ld'snir.ttauu{s snqwuSopl €'l'ErC ur tossu?JleqlJo pue deapoqtr JeoN IoI .iflprrqdeJa -d?ryUol elqEutrss?,(luEruolsnc eJ" suaturceds '€'l 'ErCur eruord ,fuurrnns aql roJ or sqerq rulerrI egl JI?q ls?ol 1?lnq 'sluopouorJo a^4cnpoJd s$eq eql $ '(6161)Elafod,(q pozu?rrruns elep o pJss?d,{q sqt olrnb eJe seI?Jq eql uI souolseurJ crlrurolo(I pu" (€16I ) uerusseo ,(q lro,,|1uo ,{[^eeq s,aderp . [od5l{ D?uurJ (896I 'pleglEH)l(truqss pet?Aele l?q/reuros Jo qcq \ 'tueuroEu?JJ?leql ]cosuell IE rlaql .slEU IF Jo sellllu?nb rel"r'{\ ur peruJoJselfiuolop q3rq^1uFllr \ -od^q Auop rlleqt eSueu? ol sarcEJoqlJuo6 x Jrp ur olel sel?rq aql uo eJaqlpuE oJeqsuooEq pesolt -ed rl?uulcurC" paluoseJdeJsourrEoJ ,{fuoue 'qldeP -ua o^?q sl"roc Jo spueg 'st?U po8Jeut pu? qldep eql Jo^q ssleluqse 8u{I" eJd pu" lot rou sdEqred ^1?l -qns ^Eur'peoJq uo pal"Fruncc" ,{lq"qold s.JoIltlEA\pasn e^?q I'srs,{leue cl8olocepJe r!-r$ Jauc eql ^l^{o[?qs l?ql lrsodap rel"n^-tamb ,{p:euud e sr se{Ero -ue8Jo sosofund JoJ 'oS 'eu]Il cgrcadsi(ue -ro.y eql euos F JO eql slerocpruoJoc ur qcu 0J?leql speqlElo^os Jo oql Jo lueutos apl^i dJe^ JoJ prte^ pe s$I slu?ld "eJ? 'U"d raddn eqt ur 'pu? slc"lc pnul '$lrpr.u eld eq pFo.r\ l"ql uorEodrt?uur3urJ ^ueegl ur Jooll qdsoqd eJoru du qlr,{ 'alrurolop peurcr8-eugpu? auolspnur -eesuErcI^opJO eqtJo elgord ? 1(Erpol tFcgrp Ei SJIrS puo4 rnruocnelS,{lesrzds sr '€, EICul Lcosu"4oql snql sr 1I sla^el olqdHArl?4s IeJeAeslD serceJo slsaS8ns 'sje + Jo puo eql le 'uonsuuod se{sJq aql -qlq ur suoll"ue^ IeJalq crleJle puE ilEnur ^{ou?r{s [BrJeds Jo 'pezlmtoJeJ prdH reqleJ JoJ snql pu" eroql pu?^l8uruees eJoqJarler qErq +"qdsoqd sarcedsuozop Jeqlo eql Jo qcEo ol elq? Is4uslsqnsJo aJueuJlureuoql JoJelqrsuodser nP DurpoJJald -uErssEaJ? nd.eJ ,{lluo',re^e^orl'swDpun snpout a^l slueurs^oureseqJ '(g16I 'euJoq o pnbe " -3Dn1dlueserdar sueuncedseqt Jo tuactod 96 -sOpue ^lluopha eos)sourl leJntrnjls u?lcl opJO :Ilnop € ^lreaus^{oqs "JIaJog { -lJle/.r Pelsll ! pJruoJ q3rq,rl paueu rrE.rg eql olur _ aloloq sercJ eql ur sut€tuerrreqlJo uonnqulsrp lErolelpuE ocuEpunq€ e^lelel eqr uro{ pereJur 'sluopouoccnsuolcBpqcJo suo[nqulsrp peleJtuolureJE e^oqv .$lcor uerJr,roprgriuan puri epplfrSo slJrnb .uor8ea slijruuoir,r '-Jedeep -ueleuorlrcodop Jo suorlqeJtuelurtuo{ p.pnrlsuoceJ rleuurcur3eqrF lcesu;4 pcilJ{joarg .g.1.l!g t qroq sapaS {l JJIRa-d qcnur taep ur 9l u?ql D:qr ieql seleur bp sE$ lequon holPqs '{lqere Fn ?3teue3,{xo uq uol3urxs-I ftse sauolsaull I smuap snoueA qJ aql ur I?Au Irt Jr€[ aql uI Alr?lnrq -suoJDarodoJd lueJoJ D psodtuo3 erB TIEEUOJ peurEU q uEluo3 ,(ar{l

VJNOCONOJ 3HJ b9l PALEOECOLOGY AND PALEOBIOGEOGRAPHY 155

they contain but are mapped as differently dominated.by Phragmodusundatu4 have only named formations or membersbecause they minor nurnbersof elementsassignable to Oul- are composedof carbonatesand shalesin dif- odus or Aphelognathus,and, never yield speci- ferentproportions or becausethey developpar- mens of Rhipidognathus- ln Clays Ferry and ticularly conspicuousinternal structures. Fairview strata, on the other hand.,Phragmo- In the late Middle Ordovician, before the ar- dus, Plectodina, Oulodus, and,Aphelognathus rival in the Cincinnati Region of much terri- are almost equally represenled,specimens are genousdetritus from the southeast,phosphatic characteristically larger, and total collections limestonesassigned to the Grier Memberofthe are smaller. Furthermore,Rhipidognathus is kxington Limestonewere the chief depositin represenledby an occasionalspecimen in sam- oxygenated,well-lit watersomewhat, to consid- ples from the Clays Ferry (but not from the erably,shallower than that in whichthe Logana Fairview). Member was deposited.Cressman (1973) esti The CallowayCreek facies, entirely of Late matesthal the Grier accumulatedin water less Ordovician age, accumulated in probably than l5 m deep, but the range may have been somewhatdeeper-water settings than the mud- much greaterthan this for at the basethe Grier flat environmentsin which the Drakes For- grades both laterally and vertically into the mation was deposited,and in quieter-water t ddepositional en- deeper-, quieter-water l-ogana and, at the top environmentsthan thosein which the conspic- Eeristic conodonts, d below. into the Brannon or Tanglewoodmembers, uously cross-beddedTanglewood Member of which formed in very shallow, more highly ag- the Lexington Limestone was deposited. In itated water. Furthermore, the lower Grier both the Calloway Creek and Tanglewood, shows a dominance by Phragmodusundatus Oulodus and.Aphelognathus are the dominant ryesent Phrag- nearly equal to that of the I-ogana, whereas conodonts; Plectodina is common, and Phrag- 'r few are assign- Plectodina dominates in the upper Grier. The modus is reducedto about 25 percentof the ' dozen species high phosphatic content of the Grier, a matter fauna.Specimens of Rhipidognathusmay con- of specialinterest to Bourbon whiskeydirtill- stitute as much as 5 percent of the collection E shallow end of ers, suggeststhat water above Grier deposi- from someunits. The Grant Lakeand Ashtock glauconitic Eel,! tional sites was supplied by upwelling with formations were deposited,in Late Ordovician with hite, rip- more phosphatethan could be abstractedby time, at various sites slightly seaward of the part, r the upper plants.This addsto the suspicionthal at least Drakes flats; the Grant Lake representswave- bial corals. The some of the carbonaterocks now included in agitatedshell-heap shoals, between and among rr deposit that the Grier were depositedbelow 15 m depth, which various faciesof the Ashlock (or rnem- tl shallowly sub- perhapsnot too far aboye the compensation bersofthe Grant Lake)were deposited in shel- r ma-v have en- depth. tered lagoons. Grant Lake conodonts are ! on the Drakes Late in the Middle Ordovician considerable mostly referable to Plectodina, Oulodus, and. fumed in water quantitiesof silt and clay spreadinto the Cin- Aphelognathus,but specimensof Rhipidogna- fflatfleld, 1968). cinnati Region from the southeast.Much of thus arc also common and, locally, may make quite lla-kes are this bypassed or was washed through bathy- up as much as 10percent ofa collection.Rl,rp- a least half the metric highs to settle in thick beds in topo- idognathus may be as important in samples erable to Rhip- graphically lower portions of the seafloor (the from the Ashlockas in samplesfrom the very Eeas the other elongate,southwestward-opening sag shown in shallow-waterDrakes, but the proportion of Hognathus and. Fig. 7.2). Thus the broad regioncharacterized Plectodinais comrnonly greater.Otherwise, the r rn rhe Drakes, in the Middle Ordovicianby carbonatesofthe two formationsresemble one anotherlitholog- &ost any spe- Grier Member was partitioned in later Ordo- ically and faunally. Horician of the vician times into deeper-waterareas in which It shouldalso be noted that the Loganaand p here and there the very shalyKope and lessshaly Point Pleas- Grier membersof the Lexington Limestone, ant formations accumulated, and somewhat and the Late Ordovician Kope Formation, rllemes marked shallowerareas in which the much less shaly grade laterally into dark, fissile shales com- ler and Drakes Clays Ferry and (later on) Faiwiew formations monly loggedby drillers as the "Utica," but is nops of facies, weredeposited. nowhere exposedat the surface in the Cincin- f the conodonts The Kope and Point Pleasantfacies are both nati Region. We have retrieved only a few con- E p€orq eql Jo ur elBJlsur uoruruoasr snqpuSopldryv 'sluopo -o'J eql leqt tuDnlcuoc ur lqau sr (tL6I) uEuI dep ara^i uon -uor eprluoporepueduoupdrcuud oql oJesnpo -ssoJcJr'ra^o^\oH sluotuuoJr^ueJel"^{-lelr\ol td luopouoJ Jo lno pue snqpuSolarydupue '?lells usrcr^opro -lerls olul slaqunu lalleurs ur selBrcosseslr anJe,\ lBuortdec raddll cnrurolop ,{DuEururop ar0 ur tuBlod PIdEsnqQuSoqdtolu t/ Jo sercedslg8noJq e^?q + spu^aN luac -rlr ojour 4?leJ avroaeqsnpoapuDd Jo sera osl" tqfiur pu? ..t"s,, eql ol IpurEJ?rusorc J ^Io q?uurcurJ I EErddrssrssql -ods'uolteu sqlJo (uacr^oplo eqt Jel?Ar-/olJeqs aql Jo snou?^ ur pel"4uocuoc rqlJo slunoJte uI qUou) lse r er0 oJ 'stuopoumtur^llJo uoll ol?qdsoqd oql pecnpoJd a^eq o^{ lq8rur ^\ou .(qlnos ) pue tueqpues -nqulsrp pe o4uoc e^?q lEql pue rets^\ ruo oq ploc l?rll Jo tu{le&dn qldep lale,r(rueqt reqlo sJolcq^euI ol se^tlauo suorsnJo eql ol lse{r eql ol selrs Jel?a\-Jedoep ^lou) 6 Pallun -uoc punoJoJd $eaEns uorSeu 4"uurcurc rrro{ rrrouoq q?uurcurJ a4flsstW 7'r'l lueJJns se uoFeu eql ^ral " Jo $lJor uercr^opJo loJ pazu"ununs lsnr eql olur rJ.{rerp'lalE&\ JaploJJo ,(poq 3 Jo leql uos equo el?p l?uollnqulsrppue {cuanboJc peugep ueeq e Eq ,{?Iu uolnqul 'llElE srr{lJoJ $uJpr^a turl -slp^q ^IrJeurFd Jreqll?ql slsetEnslaqunJ (oJeq^laslopue) 'sloJluoc {edruooou sr ereqtlnq'€'/ 'arg ur JrtEed s?lr uor8eu q?uurcurJ eql uI selrs lal"r'(-Jedeep sn Jlll.rt JoJo AroqsI uol8eu 4BuurcurcaJqlJo slusrrruoJr^ue eql 1? peleJnruncc?e^eq 01 peloJfuolur $I3oJ lruJJ eqt uro{ leu-FPII uI luopouoc tuBururop oql uI sorcedseseql Jo sueurJeds ecu"punqe .uo.t1 Jo Irlopouoc esoql -JecsE^\ 'pelou reruze se 'snqftuSoptdtqv^Fr?l rel?oJ8aqJ tuosordoJ sercedsaql JoJ eJII t srtr '(616I -cexp oJoqsuoue ur Dutpopald Sldloelder,(le^rs Jo eporu cr8elad? slsatilns^or{l sopqs Ioelq pue r PoEroJ seluod -sor8otd,snpoflO snqnuSolalldy rnrlr''nq -uou pue {c?Iq ur selEnoss?^leuojlsslr pue s'twDuSoqd r sJtrs lE pelel 'rel" r Jo ecqins-Eou ou?s oql Jo sluel -.toutvJo suourl3edsJo ecuerncco uoruuroc Di.\I ueqUou -rqequrs? ^poq '(Janq eqt Jo uoru"duoc luetsuoc eql '€', '3lg ur uaoqs sr uo4nqutsrp osoq^\ tsorJqlrue) snpoflO pue'snvDuSolaqdy'ouryot sluopouoc eql II? JoJ ecuopl\e eql ,(q pellnb -rald r^oqsI €'l tld ur's(r\L srultouSolaqdy -0J lou sr uo4eleJfuolurcrS"led ? qanoqllv .crEBIed .EIC a@s pue u,^a"Jped petEler,(lesolc Jo sueulrcedsJo eru"punqEe B s? t t ul qEco-I 't 'ttI .slueuruon^ue r -?leJ ur eseeJcurue qlr^r uecuoJ ur selrs eJoqs uaql PeleJdJeluo^?q I pcrdoJl -reeu le pelrsodap slcoJ ruo+ seldruBs -qns ro lucrdoJl ur p?ordseph\ ,tlecrqder8oat ^\olTeqs ur ecueuodurre^rleleJ ur qsrurl'ulp lnq oJeMuorte1 rleuurcurJ eql Jo s{JoJ u"ror^ ^eql 'serc4oqll uol8eu q?uurcurclsoul uro{ suoll -opJO ele'I pu? epp{ I ur polueseJdel,(lluDp -cefioc Jo sluauodruoc eJe (,,Dutpopald,, epru -unq?serJods eqt ? .{llErur^ esnmeg.€'l .8rC -rpolr?zo aql pue) Durpopald Jo suourrsads ur peleJrpurosp uounqulsrp Suhrl uo suors ' mqPu8 opt dulY puz'snpo -nlcuoooql a^uep ol uoqeu€"rur Jo lunoue 1nO 'snqQuSolaqdyJo seDeds,{q u?rcr^opJo upuec ? poppe a^?q I sqd?rE?JedSuroEa-ro1 al?.l puB elpprl l eqr lnoqtnorrll psl"unuop uI ,{Ueuqpozu?urruns sluopouoc rer0 pue serc seoJe l?u{?prl Jo '^treuo-qEq 'Jsl?a{1?oqs -."JOqllIu"rrhopJo uo uorlsrrJJoJuroql oJ olu eql Jo t.eJoqsgo,,pue ss?ul Jel?,ll-urol 'rlo,\ (palEueE -loq raplor eql a^oq?Je13^\ tllle^\ xo ndeNJo uErcr^oplo Joddn eql ur serceJrBIr Jo luelrq?qur pdrcuud eql se snlDpun d ao\s -rxrsJo $lcoJ ur paluosetdalsr,snppun snpoul I 'e , 8lJ ur 'snqJ 'sarcBJuorEou U?uurcurC -8D.qd iq uounqutuoc lerlu4sqns E Eurpnlc lle Jo saDpun d Jo ecu?punq?e^IleleJ lseqErq -ur 'saroodsluopouoc Jo uousrcoss?esJe^rp .sepnlnpJ aql sllqqxe 'qldepunururur-ue8^xo eql,{roleq erou e l?qt pouodet (996I) Jdoqos pelqnurnccE a^?g 01 (€/61) u"ussaJJ ureqlnos qftq 1? palrsodep $lcoJ u?rJr^opro ^q ,sru|| lqEnoqt'uolEulxsl eqtJo roqruoll ?u?Eo.Jeql Jo crlsFalceJ?qc s 'uopouad Pue 'uor8eUq?uurcurC eql ur selrs Jale^\-Jedoep-DuSosapoqv'D apouil sopnlcurqorq^\,luea eql sP peleJtuelul oJE l?rli$ lp peurloJ $lcoJ -urluoJ srql 'sercq ta13/d-Ja,rlolpqsuI u^\ou)l uI urnurxPur $ snlDpun snpou,tSDlqdttdli.u:es -un ,(lefueJsr lnq uolSurxe-Ier{l Jo laquew ,edo) -eJdeJsuauncods Jo eJu"punqe e^U?leJeql JeuC eqtJo serc€Jrole^l-radoop pu? eqt Jleslrurolloq oql uo lou 'o^oqElsnf 'eu?8oT eql uI polueseJdeJ,(ltuEpunq? flJreJ Je13^1IOOC et0 Ur pe^rTselelJosse sI pue snry| sr leql ssrcedsorloxe Jo lue8uDuoJ lueuod -DuSoqdJoLuVl3ql,{lelrT sr tl 'qtdep ulnIIIIuIlu -uror uoruuroce 'snqpuSoqdnruy"Jo 01elqeleJer -ue8 xo eql suroBoquo psrrrJoJ ? el" essql 'uol8eu D?uuriurJ uJelse^{qilou ^\oleq,{lleteuaB (euolseurr.Iuofurxe-I orIl Jo) Jequew ?u?3 eql Jo ecEJrnsqns0q1 ur mqn oql uJo{ sluopo

YJNOCONOJ AHT 9SI PALEOECOLOGYAND PALEOBIOGEOGRAPHY t57

Eton Limestone) dow the oxygen- bt .lmorphogna- i ttre cool water I irself. qFclmens repre- ., 'k maximumin Epreted as the rimati Region. ;y .4s rine1on, thought /-s','tl'; rr accumulated qnh. exiibits the 'P. undatus of all E in Fig. 7.3, I Fl inhabitantof r the colderbot- E- of the more tidal-flat areas fddle and Late fugnathus, Oul- d the ozarkodi- rens of collec- 4ion lithofacies, r importance in rl shallownear- increase in rela- Fig, 7.4. Location ofthe DeseretBasin and adjacentfeatures ofthe Mississippianof the westemUnited States. f closelyrelated Redrawnand simplified from Sandbergand Gutschick (1984). 73 | show Plec- ladLJ (an almost ter). as inhabi- northern Wyoming thought to have accumu- nental interior, and in the Deseret Starved t My of water, lated at sites marginal to those in which eva- Basin, which was separatedfrom the Antler Modus proges- porites formed in the Williston Basin (Sweet, Flysch Trough on the west by a narrow sub- a onshoredirec- t979). These featuresin the distribution of marine rise, or sill. The generalarrangement in r norcd, was cer- thoseconodonts square with the onesdeduced the Deseret Basin and adjacent platform areas rt in tidal-flat from the record in the Cincinnati Region but of Mississippianrocks of the Anchoralis-Iatus ti Regrbn.I show ofer little more as to the actual ecologic Zone is shown in Fig. 7.4. From the distribu- re is no compel- controls. tion of conodonts in the several lithofacies shown in Fig. 7.5, Sandbergand Gutschick I dataofthe sort (1984) have also inferred the habitat of con- irn rocks of the odont species that represent the genera indi- paleoecology,western r profound con- 7.4.2 Mississippian cated in that figure. UnitedStates En water depth Dark brown to black mudstones, phosphor- rolled distribu- Sandbergand Gutschick(1979, 1984)provide ites, and phosphaticshales are the deepest- E west(north in accountsofthe distributionofconodonts in the water depositsrecognized in the Mississippian Eti Region, spe- Mississippianrocks of westemUtah and adja- transect summarized diagrammatically in Fig. nively moreim- cent Neyada that are rich in detail and of ex- 7.5. Sandbergand Gutschick(1984) conclude blomitic Upper ceptionalvalue in building up a generalpicture that thesedark-colored rocks formed in cold, Whus a d Oul- of conodont paleoecology.The rocks in ques- oxygendeficientmarine water at teast300 m brodontide con- tion weredeposited on and alongthe westedge deep along the axis of the DeseretStarved mon in stratain of the broad carbonate platform of the conti- Basin. 85t q petueseldoJ lsuSo4JDg 'seuoz FqoJ /$gnr[ I PeESap ueeq 4l r€elodos FqF ! o (t qr serJads ?'J o Jo , f Fe slsuaqoy { fea€ t? pe^rT IE oil ai qr Jo slsnpr^ iF!; iii rlrnslp qsns " a F JJIB,I{-JS,IAOI -{ rE reresed erll !9 o ii -| FtuaseJder eJ" ! r:pErporuoud .o 0i !- pozrlercods FB o .InuSoUnS D .od a -Juoz Jloqd lll \! 2 limJ eql pelr d? :9 26 JJ Foq lBql slsea ae^ I srqf sarseJ g6 a F$e_\oJeJ u03q E ,rnuwoJ mql _o Fe tuaqpues So FueseJdo)I H. g, 1i t urqlt,$ flurel 6{ a :$ tal [t-'ru]oJlqd gF93 c I lles-/doll?qs 8 EJdeJ sercq ^E il fues ueaq 1e,{ :g a.nqlo Jo olup zi g= |ues qtru lsee R? rF slJol rell?l 1)lJ iE€s 'setrrxoJ .' :=JqI 'seuols iz o :i|su a requq D ;g I Forq 'peJoloJ I snlE.I-srTeJoq3 9a^o s it I rqrJo ls?g iT D Jaq8rqse1$ s T rbF aql urt(rop t 'esJnoJ aJe Jo !:'' ,! I lJo lJle^\ p01e I EdJp area ,{lq 5 D rsnt ruJoJl?ld ri ri E t aql uo pel?l it r Jsaql 's^rou AAI FoJd saJnlxel z; io Iredsorq pezrl :a Tn qll{r PI^\ tt *drep eql

LAI{D PALEOECOLOGYAND PALEOBIOGEOGRAPHY t59

The deep-waterdeposits intertongue east- the reconstructedforeslope, including its pre- ward with thicker accumulationsof dolomi- sumably dysaerobic,deep-water toe. The ab- tized biosparitethat include encriniteswhose senceof BaclrognarrrJsspecimens in axial de- textures proclaim their formation as debris posits of the DeseretBasin, coupledwith its flows. Theserocks, thought to have accumu- occurrencein samplesfrom both poorly and lated on the foreslopeof the broad cratonic well-oxygenatedslope environments, suggested platformjust eastofthe DeseretBasin, proba- to Sandberg and Gutschick (1984) r}|lat Bac- bly weredeposited in the murky but well-aer- trognathuswas a swimmer,but that it confined atedwater of the aphoticzonel the encrinites,its swimming to the aeratedwater just basin- of course, are built of material that moved ward of the slope floor. In other words, Bac- down the slope from the shelf edgeor from trognathus, like its close relatives, Scaliogna- siteshigher on the slopeitself. thus and.Doliognalhus, was mesopelagic,but East of the platform margin, rocks of the An- its habitat may have huggedthe bottom aboye choralis-LatusZone arc thick-bedded,light- the oxygen-minimumzone. colored, bioclastic limestones that are replaced Gnathodus and Pseudopolygnathusare also farther eastward by more thinly bedded lime- representedby specimensfrom upperand mid- stones.These, in turn, gmdelaterally into do- dle slope deposits, but by very few from rocks lomites. Sandbergand Gutschick infer that the that representslope environments interpreted latter rocks should merge even farther to the to havebeen below the oxygen-minimurnlevel. eastwith sandydolomites, perhaps with anhy- Becauseof the latter fact,it seemsunlikely that drite or other evaporites. Those facieshave not individuals of either genusever strayedmuch = yet beensampled, however. In general,all these abovethe bottom or out into water abovethe € facies representdeposition in the relatively deepestparts of the basin.In short, speciesof shallow-waterenvironments of the carbonate Gnathodus and. Pseudopolygnathusmay well platform. 3 All those environments were cer- have been nektobenthic,with habitats that E tainly within the euphoticzone. "bottomed out" basinwardagainst the oxygen- Representatives of Bispathodus utahmsis minimum layer. E Sandbergand Gutschick, 1984, and Polygna- Eotaphrus is confined to rocks that formed e Ihus communisBranson and Mebl, 1934,have high on the slopeand in adjacentparts ofthe beenrecovered from all but the mostnearshore shelf edge; Hindeodus is commonly repre- E e facies.This near-ubiquityof occurrencesug- sentedin strata depositedon the outer shelf; .E geststhat both specieswere pelagic and inhab- Pandorinellina appears to have characterized !, ited the euryhalineenvironments of the eu- the inner shelf, in environmentsaboye wave photic zone. basefand. Mestognathus, a closerelative ofboth Scaliognathus and Doliognathus, curiously Pandorinellina ' and the cavusgnathids, may specializedand biostratigraphically very useful well have been adaptedto hlT,ersalinelagoonal E prioniodinidesof the family Bactrognathidae,environmentsalong the innermost margin of are representedin the deepest-waterdeposits of the platform. Thereis little in the reporteddis- € the Deseret Basin as well as in the much shal- tribution of conodontsassignable to any of lower-waterstrata of the foreslope(Fig. 7.5). these genera that proyides a definitive answer Such a distribution logically suggeststhat indi to their mode oflife. Their absencein slopeor viduals of these genera were also pelagic, but deep-basindeposits suggests they may not have : liyed at greater depths than did Bispathodus been petagic, in the manner of Bispathodus utahmsis and Polygnathuscommunis. In shor1 and Polygnathus. Possibly they were also : speciesof these two generawere probably me- nektobenthic. s sopelagic.Their depth zone may well have It is always risky to generalizefiom obser- been definedby the well-oxygenatedbut still vations made in limited areas,no matter how rnurky conditions of the dys- and aphotic sophisticatedthe studiesor convincingthe con- zones. cfusions. However, it may be noled, that Pan- Bactrognathus,a distinctive prioniodinide, is dorinellina is the acknowledgedancestor of the representedin sarnplestaken from all parts of Cavusgnathidae and. that Cavusgnathus(and, dir aqr uI srqJ Jol?nbeeqlJo quou lsnfEel? el?Euolau" -Je^ pue IIUJaW sJod?dlueuodrur ul peu?u 4mpoqpuS ur pel"nlrs ers^\ leql (9 , 'ErC)sursEq pueloJoJ ueeq eAEqpuE ^q'pezuelcsJ?qJ 'pogquopr eJ? lropouoc qlr^r\ JO ur?qc 3 ur PelalnrrrnJce ?cuourv quoN qorqla'sel'?Jorqo^rlcuqsrpJo raqunu Dsougop p ioleq $lcor l"luJurluoJp x Jo $lJor uEruB^lfsuuJd uo4nqqslp Jroql pu? 'u^\ou)I lla,r\ rroJ 'slu?puecsoppuE sJolsecrre Jreql Arousr ,truouoxel Ie afcueueEJroql :slcoJ^lqeuosBeJ uelu EIII IUAUItlloJd^usra^rp Jo osp ,(lqeqord pu? stuopouoc ueue,r1,{suuo4 -e.1lJ,(suuedur slrssoJuoruuoc eJ? sluopouoJ FPF 'Peluosel Jo sletrqeqpuE slrq?q eql otur lq8rsw elq?np siuopouol uDtuDqtsuuadIo tSopraoapd E'r'l )eIoIIl seuoceq sepr^ord slodor Jo sles o^U aql IIlo{ uorl *l IsJrdft e ur -?ruJoJurJo uon?urquroc E pue 'Jo^e,{roq'lse8 olp -8ns pFo^l tuaruntff eqt Jo euol eql uI 's0l?1spolrun rue -:{rotseujrJ 4mpoqpu? -uls l"uorsecco se leeJEse eJBsocueJe.grp ^cueposoql -$e { eqtJo u?rddrssrssrl^leqt ur (t86I) {crgcs ae 'stxoloqlav J[" loN sJeueruur"uec uo uourdo Jo socuoJoJ -1nCpuE treqpu"s pagquaprselreJolq uuoJ I utq 'oluosrtlg Jrp crs?q,{ll?elcer? eraql eJurs 'sluopouoc u?ru -l"ld aglJo IeJo^osJoJ^q sorcqorq uerue^l,tsuued oJ seql ur J?ad -B^I,{suuedJo ,{tolooa eql tuu3edseJsJeu?rx pue u"rddrssrssrjl Jeqlo ur slell?J?deJ? eJeql EUOJhUo eUU qe uo luerueerEele:oueE sr oJeql leql lsa8Ens sn\I 'snqtDu8sn^n) paJo^eJ s"ol? eJoqs rlPr0 slrssoJ,r\eJ o1 Eurpeelsrureq plno^{ lI (986I) op?^{Spu" -ur oql u?ql 'Jolc?J?qc^q ouu?ru-puxou eJour .lnq I slueuruoJ '(516l) uueures*g pu? Ie{coH '(0861 'l.t6I) Jo flqeqord pu? 'eroqs,UoJequq erenat?ql IuoJer AII?qrur lDlcoH suodeJ pelueurncoplla,y\ 'o^rs slueuruoJr^usozrJalaeJeqc ol,suIoes snpoaput H lJo JsPqaql 1? -uerloJdruoc^q uI elluereJur Jo ,(llceJrp reqlre 'E'?'t uoqcas ur pelou eq Lr sp'${coj u"ru : ?rl uI eloN Peuqlno el? s?es^ u?rue^l,tsuued ur serc"Jorq -?^[,(suueduI'slueuuoJr^ue eJoqsJeou'J91",{r tEr IEJeueBoql eserll Jo uoqaluoJoJrp Ien?ds pu" uoqerrrJoJ -^{oll"qs luasardeJl?ql $looJur sluopouoc FiJ uEru?^I.{s aql peure oe leql sroto?d (t861 'renrg uo^ lu?ururop^le sql oJeq^{oslo eJe (sn DuB auoJ JrqlrTeql pu? IuleW uI pezueruuns) sroqlneoc snor -oppv 'e/-]ftlar u?rup^I^suued{llueurruop slr fxtnqulsrp eql rLci6I) uu"ures '(0861I$p0H u.ro4u^lerpor pue pogrpoI I luourl esu cn?ls .9.1 t IxrE -uotpry{ 'S n eql uI sl$odep fuelueulpos ueEe,{l^suuadcrlc,b Jo uogrsodepJo slueuuorr^uo poleJuJ ttd Auouuroc eJ? Jo Jequrnu |f|Illsrp-n Jo sles i Jo uorssoccns EsruE^l^suued 0.\;--_-_-* tssrsJad lsour rFJo su"d uI 'snonuq D sdnof Jeqlo : -ure-€ -rauggo E .{ltualsrsJ3d r PrI? lse^{ reql go .iq passere ttJo ,{Iuo oJa^1 Fo pu? suGld {du1o3 ? urroJ .01 Dqter?l^I-?lqc :l Errrerp su?eJls qqu?nb leoJE v a -l> ql Jo pue IIle I l|Iros 3qI sul"l t€ua a,r.r1ce,(q GXI are.r l?qa Ip-ruelar aqt ,tq EPrOq Se^\ eol"

09r PALEOECOLOGYAND PAIEOBIOGEOGRAPHY l6l

areawas borderedon the north and northeast middle limestoneis followed by a meter or so by the relativelystable cratonic interior and on of abundantly fossiliferousgray-brown shale, what were then the south and northwest sides which is typically (but not invariably) intro- by active rangesoffolded or fault-block moun- ducedby (or includes)a distinctivecomponent tains. The southernmargin and T the southeast- offissile black,phosphatic shale. In this "core- I em end of the foreland-basinchain received shale" interval, conodont diversity may drop A great quantities of terigenous detritus from off, but frequency of occurrencecommonly D streamsdraining the Appalachianand Oua- reachesa rnaximum preservation C and is gen- chita-Marathonfoldbelts. This spreadout to erallyoptimum. Representativesof Gondolella f- form a complex of laterally shifting alluvial are almostcompletely restricted in their occur- I plains and coalescingdeltaic systems,which rence in Kansas and Iowa to the core-shalein- a wereonly occasionally(and then briefly)trans- terval, and specimensof the prionidinide 1d,- o gressedby offshore marine environments. Far- oprioniodusare more numerousin this facies 5 ther westand north, the basinchain was more than in any of the othersin the Kansas-Iowa persistentlyoccupied by the sea,sediments are cyclothem. offiner grain,and the recordofconodonts and In the basatpart of the "upper limestone," other groups of fossils is more nearly con- which succeedsthe coreshale ofa Kansas-Iowa tinuous. cyclothem,maximum conodontdiversity is re- In parts ofthe foreland-basinchain that were established and specirnensof the Idiognatho- most persistently occupied by the sea, the dus-Streplognathodusplexus continue to dom- "0 Pennsylvanianrock record is made up of a inate in frequency.Adetog nathus, represented successionof cyclothems. These are repeated by few, if any, specimensin the lower part of setsof distinctive rock types,which record a upperJimestoneintervals, tlpically becomes number of transgressive-regressivecycles that more abundantlyrepresented upward in those are comrnonly regarded as the results of eu- intervals and may regain a dominance in the r the U.S. Midcotr- static rise and fall of sealevel. Heckel and Bae- uppermostpart that carriesover into the lower, semann(1975) and Swade(1985) have related marine part of the superjacentoutside-shale the distributionand frequencyofconodonts to unit. in Merrill and the lithic componentsofa numberofthe Penn- As indicatedin Fig. 7.7, the typical Kansas- n governed the sylvaniancyclothems in Iowa and Kansas,with Iowa Pennsylvaniancyclothem is viewed by rbdon of these the generalresults summarized in Fig. 7.7. mostgeologists as the recordofa transgressive- are outlined Note in Fig. 7.7 that sandy"outside shales" regressiveevent. Thus, from the relationship -r in comprehen- at the baseofa typical Kansas-Iowacyclothem betweenconodonts and the lithofacies that rep- r|s by Heckel initially recorddeposition in nonmarineenvi- resenl vanous stagesin thal transgressive-re- =mann (1975), ronmentsbut, in their upper parts, pick up a gressivehistory, it shouldbe possibleto recon- E misleadingto few fossilsthat indicateshallow, nearshore ma- struct a general ecologic model. Such a model lrtemEnt on all rine environments.The first conodontsto ap- hasbeen developed by Heckeland Baesemann y of Pennsylva- pear in theserocks representAdetognathus arLd, (1975)and Swade(1985) and is showndia- dearly basicdif- Ellisonia, but others referable to Hindeodus, gammatically in Fig. 7.8. matters.Not all Aethotaxis, and. the ldiognat hodus-Strepto- Heckel(1977) concludes that the phosphatic r occasionalstri- gnalhodusplexus follow shortly. In the "mid- black shalecomponent of the core-shaleinter- rent would sug- dle limestone,"just abovethe "outside shale" val accumulatedin anoxic bottom water be- lion of informa- in a typical cyclothem, the inyertebrate fauna neath a thermoclineand thus representsthe qrorts proYides becomesmore diverseand is much betterrep- deepest-waterenvironment recorded by any of r and habitats of rcsented..Adetognathus may continue to be a the lithofacies in a cyclothem of Kansas-Iowa Fobably also of prominent memberofthe conodontfauna, but type. From this conclusionit followsthat con- E diversity commonly is greaterthan in shaty odonts commonly representedin core black midcontinental rocksbelow and dominance begins to be shared shaleswere not only pelagicbut werealso seg- in a chain of with conodonts of lhe ldiopathodus-Strepto- regatedin depth zonesin life. That is, Goz- rere situated in gnathodus plexus. dolella, Idioprioniodus, Neognathodus, and b equator.This In the typical Kansas-Iowacyclothem, the various members of the ldiognathodus-Strep- 'plm erDJouonnqulsP equcsopt3q1 sr4euI?r i2uz luerudole,rsp paleerJ ere.{\ uropoq -ed IEre^aseql Jo elq"reqdrcep lsolu eql eql uo suourpuocJrxouz ^q 'g'1 '6rg ur palseSllns tuounqulsrp ,(lq?qoJds"^\ 1r lnq ^IpeoJs,n appuoC sr s? 3I 'sreqlo eql u?ql uurnloc JolB^reql Jo PelloJluoJl?ql lolJBJP ue3qe^eq lou ,s ued Jadeope ol eJrlur pauuuoouaeq e^?g lsnul .t?topuo9':tl ^?u.r -__:ii::::ii::::::i .radqldac 'aulrolllreqt er0Jo rote,'(\crqoJ*s^p 'le^Jolur el?qs-oJoc eql ol seJueuncco uesr 'ploc eql pauuepuaeq e^"q A?rrJeuoz qldep -JerlY quoN slrJo [ueur uI palculsersl qcq,{ s,Dlplopuo)^q lBql s,'aoIIoJ lr 'lE^relur el"qs 'D appuog lnq :uolloq eql o^oqE sass?u] -oJoc eql Jo slueuodruoc epqs:^eJEpu" -Ic?lq Jal?a pe1er035ql ur aJaq \euos po^q 0^3tl eql 01 pauguos sr D alopuo9 Jo uo4nquFlP lsnru 'BunEJelsqs-Icqq oroc oqt Jo slueuod paJ" 3ql Jr pu€ :eurlsouueql? 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YINOCONOJ AHJ z9l PALEOECOLOGYAND PALEOBIOGEOGRAPHY 163

dense,oxygen-poor water of the thermocline, rill recognized don tS ihe Adetognathus biofacies in to which i Gondolella was best adapted and in 1962and, in subsequentreports (Merill, 1968; which ldioprioniodus also thrived. As Heckel von Bitter, 1972),it hasbeen suggested that ra- *" (1977) noted, that water may also haye been tios between specimens of Adetognathus and, rich in settling organic matter, phosphate,and Idiognathodus (aQSi or Streptognathodas, which o heavymetals, and thesemay also haveplayed dominate environmentsmore offshore,might .9* a part in defining Gondolella's depth-zone provide a quantitative senseof distancefrom habitat. shoreand a measureof relativesalinity. ** o { Adetognathusand. Ellisonia were certairLlyat Environments intermediate between the the otherend ofthe ecologicspectrum in Penn- shallow, well-oxygenatednearshore waters sylvanian seas.The common occurrenceof with highly variable salinity and the much specimensof Adetognathus,for example, in deeper,colder, more dysaerobicwaters of the rocks that representobviously nearshoreor thermoclineseem to have supportedthe most ll marginal marine environments(like the out- diverseconodont biotas in the Pennsylvanian. side shale FiE lr I of 7.'l), in dolomitic stratathat Throughoulthe Pennsylvanian,dominant con- It I intertonguewith evaporitesequences, and also odonts in these intermediate environments (in greatlydiminished abundance)as compo- were members of the ldiognathodus-Strepto- nentsof higher-diversityconodont faunas that gnathodusplexus, and rocks that accumulated include forms associatedmore commonly with in them have been assignedto a ubiqui- normal marine conditions suggeststhat lde- toi]s I di ogn at h o d us - St r ept og nat h o dus biofacies tognathus$tas earyhalineand adaptedto life in (Merrill and von Bitter, 1984).But theseinter- well-oxygenated nearshore waters that were mediate environmentswere also the ones in susceptibleto wide variationsin salinity.Mer- which the closely related anchignathodontids

Fig. 7.8. Hypothetical c.oss sectionsofPennsylvanian seaat maximum extent in the U.S. Midcontinent. Upper diagram relates sedimentary facies to inferred quasi-estr.rarinecirculation pattem; lower diagram shows inferred living distribution of conodontsas reconstructedfrom tieir occurrencesand frequenciesin various sedimentarv facies.Redrawn and slightly modified from Swade(1985).

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YINOCONOJ :IHT v9l PALEOECOLOGYAND PALEOBIOGEOGRAPHY 165 nd commonly harsh environments controlled the distribu- Idioprioniodus and, Gond.olellain Pennsylva- conglomerates tions obserYed. nian cyclothemsin Kansasand Iowa suggests r maryinal en- that speciesof those generawere confinedin r black shales life to a relatively deep part of the water col- 7.5.1 Depthas a factor : rnterpretedas umn and also that their depth zone may haye rposits. Heckel Many of us who have written about conodont been defined by the cold, dense dysaerobic lansgression of paleoecologyhave discussed the distributionof water ofthe thermoclinethought to be respon- rigenousinflux variousspecies in termsofwater depth,not be- siblefor anoxicconditions on the bottom. Un- r['trt have pro- causedepth pel Je is a significant ecologic fac- fortunately,from studyofthe skeletalelements Nronment un- tor, but becausea senseof at least relative of cold-waterOrdovician and Pennsylvanian br- so that the depth may be derivedfrom the textures,struc- species,I havebeen unable to isolatemorpho- er-e foundered tures, and other fossils in the sedimentary logic featuresby which other cold-waterforms @uent deep- rocks from which our conodont collections might be identified. b offshore,an- havebeen made. Although depth itself may not ['fine-grained have exerteda primary influenceon conodont 7.5.3 Nearshoreand I|c matter set- distribution, factors such as temperature, light ofshorefaunas rded by super- penetration,lieht intensity, turbidity, energy, All threeof the modelssummarized in section ble directlyon salinity,and water densityfluctuate directly or '1.4relate the distribution of conodontsto on- rb situations inverselywith depth,and oneor a combination shore-offshoretransects reconstructed from the Ie explanation ofthesemay haveexerted the direct control on distribution and nature of the sedimentary- r insistingthat distribution. I suspect,for example,that tem- rock record.In all threemodels there is reason- r inrerpretedin perature,not depth, was the important factor ably clear distinction between an offshore governingdistribution of speciesof Amorphu group of speciesthat may be relatedto stable gnathus and, related balognathids.That is, temperatures,"normal" marine salinities,and those speciesare representedin highlatitude limited turbidity; and anothergroup that ap- Ordovician rocks that formed in cool, rela- parentlythrived in nearshoreenvironmenls ized in Section tively shallow water, whereas at lowlatitude characterized presumably by harsher, more rencesas to the sitestheir remainsare largelyrestricted to the varied environmentalconditions such as great t can be made depositsof deeperwaters in which tempera- fluctuationsin temperature,salinity, and tur- Jationship be- tures may have been comparableto those bidity. It is ofinterestthat conodontstypical of Etary rocks in nearerthe surfaceat high latitudes. the offshoreand nearshoreends ofthe environ- :- *'as irnplied mental spectrumin all three models have a r and lateral- numberof featuresin common. 7.5.2 Temperatureas a factor rd by Seddon In all threeofthe situationsdescribed in Sec- and Fihraeus Diferences in temperature were probably re- tion 7.4,species characteristic of nearshoreen- re also learn sponsiblefor development,in the Ordovician, vironmentsbuilt apparatusesof relativelylarge Ering distribu- ofdistinctive conodontfaunas in the high- and elements, with a reduced nurnber of discrete ;dures of both low-latitudemarine realms.This conclusionis denticlesof circular crosssection and little, if hion that the suggestedby the fact that rare invasions into any.white matter.I alsohave the impression t have yaried higher latitudes of speciescharacteristic of low thal elemenlsof nearshorespecies are more nhic. On the latitudes were accompanied by accumulation variable in morphologicdetail than those of i is rarely pos- of vaughnitic carbonate rocks that indicate offshore species,and their apparatusesare rnical, or bio- concurrent invasions of warmer than usual more variable in composition. Furthermore, tsolled the dis- water.Also, as noted in Section7.5.1, the few note that Ordovicianand Triassicrocks repre- r example,that typically highlatitude speciesthat migrated senting nearshore environments have pro- lhids were, for from time to time in the Ordovician into the duced all of the "fibrous" elementson which lftalrs of shal- low-latituderealm becameestablished there in Bransonand Mehl (1944)based their concept Hts that were deeper-waterenvironments that were probably of the suborderNeurodontiformes. Finally, it zted tempera- similar thermally to the high-latitudeones in is clear that at any time speciesdiversity was linit_v, but it is whichthe specieswere most widely distributed. considerablylower in nearshorethan in of- icron of those As notedin Section7.4.3, the distribution of shoreenvironments and, becauseit is my ex- tros e puz a)ul -eq seIJJrsI?srtoloet ur lserelur13eJ3 Jo psrlJoJ 'seuneJeJoqsJ?eu Jo sJeqtlleuj lnba u? Jo uorl -rno sr ,{qd?JEoeAorqool?dJo lcefqns eqJ^lluer era,r^eql 'J}^e/:l.otl 'snpou?DJ{d Jo selceds @Lrrs€reg pu? 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VJNOOONOJ :IHI 991 PALEOECOIOGYAND PALEOBIOGEOGRAPHY t67 ied denticles causeofthe light it may shedon the positionof ley Province in the late Ordovician of the ner. Their de- major crustalplates in the past.For this reason, wann-water realm. tateral differencesin con- hdovician, ap- a number of defailedstudies of conodontpa- temporaneousconodont faunas also permitted t apparatuses leobiogeography have been published in the recognition of British, Baltoscandic, and Med- res" Develop- lastfew years.Most ofthesehaye been brought iterranean provinces in the cold-water marine inilar history. up to datefairly recently(€.9., Clark, ed., 1984), realm, in which conodonts may have lived in i:s are repre- so I provide only a brief summaryhere. subpolarseas well above 60 degreessouth of I and the ele- the equator. ershore fea- I-ate in the Ordovician, as noted in Section tte primitive 7.6.1 Late Cambrianand Ordoyicqn paleobiogeography 6.3.2,conodont species diversity declineddra- ,dina," clearly matically, and this seemsto have led, by the mr-rronments. Miller (1984) notes that both classesof con- end ofthat period,to virtual eliminationofthe F ous to use odonts appear to have originated in the Late fauna characteristic of the cold-water realm. r elsewherein Cambrian in warm, low- to midlatitude seas. Stocksthat survivedinto the Silurian (i.e..the iks to the en- By earliestOrdovician time, however,repre- Icriodellidae, Prioniodinidae, Spathognatho- E OrdoYician sentativesof both groups had spread into dontidae, and Panderodontidae)are either higherJatitude seas, and Cordylodus (a cavi- onesthat werewell establishedin low- to mid- rlusion from dont) had becomeessentially cosmopolitan. A latitudeseas ofthe Ordovicianor aresurviving Etioned that, pair of major eustaticevents in this Late Cam- relatives(e.g., Distomodontidae) of onesthat I paleoecology brian-earliest Ordovician interval are thought were. rI To be sure, to hal/e been influential in directing the devel- --<)r eYen the opment of the Conodontaso that, by late in I a generalaf- the Tremadocian, very different faunas had 7.6.2 LaterPaleozoic and Triassic paleobiogeography fie. shallow- evolvedin low- and higherlatitudeseas. ei'en at this The faunaldifferentiation outlined by Miller Reported Silurian conodont faunasare surpris- teep in mind continued through the Ordovician, when the inglycosmopolitan. However.46 new species hioniodinida manne realm was clearly divided into two are described from the Lower and Middle Si- ue explorers major biogeogaphic units (Sweetand Berg- lurian of New South Walesin a recentreport mid-Pennsyl- strijm, 1974,1984). I now preferto regardthese by Bischof(1986),which may suggestthat Sil- d nearshore major units as warn- and cold-water realrns, urian cosmopolitanismmay be partly a result Ere frrmly es- althoughthey were originally describedas the of faulty knowledge of Silurian conodont ed Ellisoni- North Atlantic and North American Midcon- faunas.It is alsoofinterest to notethat Silurian tinent provinces.Descendants of the pioneer conodonts have been collected largely from lineageof the Conodonti,the Teridontusstock, rocks thought to have been deposited equator- figured prominently in faunas of both the ward ofthe 40th parallels(Charpentier, 1984). warm- and cold-water realms and, as Berg- Klapperand Johnson(1980), whose compre- r I notedthat strdm and I pointed out in 1974,there was a hensive review is authoritative, confirm that rs of Triassic not-surprising parallelism in development. conodontsappear to have been restricted in the rctively, had Only a few cosmopolitan species existed, Early and Middle Devonian to more or less hde that dur- mostly representativesof Drepanoistodus and, tropical areas.Early in the Devonian, ende- :n history the Panderodus,but also including the cavidonts mism was relatiyely high, but later in the pe- rts may have Dapsilodus, Walliserodus,ar:.d Ansella. riod, with increased rnarine transgression of ) s.rggestions, By the Late Ordovician,and possiblybefore, cratonic areas, endernism decreasedand the ilerable skep- distributionofconodonts had cometo defrnea nurnberof cosmopolitanspecies increased. Al- E Eell-estab- number of biogeographicprovinces in the though Klapper and Johnsonnoted that most frough it has warm- and cold-water realms. For example, a conodont genera were uniformly distributed, = h their his- combinationofR- and Q-modecluster analysis they loggeda number of differences,at the spe- mmopolitan of data from 26 sites in North Arnerica (Sweet ciesleyel, between the conodontfaunas ofvar- and Bergstrdm, 1984) permitted discrimina- ious epeiric seasof the Early and Middle De- 4rh) is cur- tion of an equator-straddlingRed River Prov- vonian.It wastheir choicenot to formalizethe al circlesbe- ince and a soinewhat higherJaiirde Ohio Val- endemicunits asproyinces because such a pro- (u"rtEuurJurJ) uoq?uJoC Epnles er{lJo ,{8oloc &lllqrssodeql ezruSocer01 lsrg eqt s?^{sluopo -eoapd pu" .S .J ,pleglpH (896t) -uoc crsseul uo lodoJ s,epelqcnH 'g9l^qd"$rlerts DdDd.to]d ta^rns 896I . 69-t loaC S n 'Je^a,Ytoq'pezuolc?Jeqc Jo peqsrJq?lseuoeq 'DlJnlue) J?rluecJo (u?rcr^opro) ouolsour.I IIJ or epmc uolSurxq eql slueuruoJrlue e,\eq saour^oJdIBruroJ oN Ee"tu?d Jo slsEoc -J Jo J"uorlrsodep \- €rsqpuss puE,{qde$rtBrlsoq-I'GL6l) g'us{usserC 1SO/(pue lsee eql uo s"uneJugo^rloq socuoJoJrp '92 U T6-988 '0bt l?rcur^oJd s1so63ns'sl?p ,{eJ uo pes?q q8noql rlJ rJ"tu?^l,ts -l'961 tlowaw wv Jos ursq?Dur^otd -H 'sepoqu loag !'.I I 'srs{pue (y961)s.requedreqC 'u"ru]Jod pu? 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'treqpu?S'retlrg uo^ -tpoLtD) Jossv qlnos {\eN uJeNe?r{tpllulIIo{ Sluopouoc Ueu xssrl{ 'uelu '^Fu4soJetul 'pedsns suorsnlcuocfue eleur -ng5 e1ppq41pue,{1r?A (986I) O J D Joqcstg Fre Puog 5q1 01 s? AreJos eJo^\?lep lEql pelou eq 're^el.roH 6t?I-ttl 'g vrDuD-l 'ee"3u"d lD [auauuor 'spuoqootuopouocuercr^opro lrqsq rrqlueq Jo seprsalrsoddo uo podola^op e^?q -:t 'c Jo tuDeco l IIFrehl -oDleu pesodoJdeql puE 'senrunururoc'seJur seuneJluaro.Up crequ aqlJo eJns g -_irun e14s -^ord (946I) g .I'sne?rq"c pu"'.){ ^slu -nuopouoc J'seqrsq -olc snoreJruoqJ?cel?.I qlv( 'lEql uorsnlsuoc lll aql peqcEeJserJeds ruJoJ u?ru?,r1,{suue4 ;t) t{ '9 '[gro]^l seJuaraJau lEJ€oJ 'nzt pu" u"rddrssrssq^lJo uo4nql4slp eql Jo srs sf loag'Iuto -,ipu? 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Fo6oaSoalDd leql 'oJoqsJour polrsodep$pol ueruo^eo leddfl FiJ uEruE^I,(s (t86I) s,JerluedreqC eeEtuEd Jo aprs lse^r ul (296I) re@eg fq peshep aueqos l?uoz Dursodap roJ eql uo ecur^oJd uEcuau.Iv quoN 3 pue 'edoJng -orq eql Jo ,tlr[q?crTdd?IesJo^run lsourp eql n 1086r)- pJluec ur ecuhold ({lDlleqcsntr^{ lo) rluelu 'slolleredqlot eql ,{qqlnos pu? quou pepunoq ,n8 loa' loti -JeC e '"e?8upd eprs aql uo aour^ojd uI:quuoJ-Pltu Jo lsEe lleq epnlq?l-,!{ol 3 ol uEruo^a(I el".l aql q sarJ€Jol€qs ue,{q1e1 z pozruEoJeJe^eq sJoqlnE luenbes q8norqlpeuvuoc aq ot penunuocsluopouo] il|'H d 1e{ceH -qns e3?,(ueJo stuopouoc Jo uorlnqutsrp sql ..'?0s dS nlawv uI eJnleoJ ? sE rusrprcur,lord lsa8ilns o1 lsrg eq1 curede uEruo^oo olaedes qrEs Sutru"u ueql ?uPIPul ur D Jo auo pue uo4nqulsrp Jreql ur eJoIII Ou ' ' ',, Ol pelunorrrs e,\Eqplnor\ ampas ^lqercurloJdJo VJNOOONOJ IIHJ 89r PALEOECOLOGYAND PALEOBIOGEOGRAPHY 169 lion and one of in Indiana, Ohio, and Kentucky. Geol. Soc. Devonian and Mississippian rocks along the r as a feature in America Spec.Paper 95, l-34. Wasatch Front and Cordilleran hingeline. f an1-'age. Sub- Heckel, P. H. (19'1'7).Origin of phosphaticblack Brigham Young Univ. Geol. Studies 26: tO7_ lrd a Tethyan shale facies in Pennsylvanian cyclothems of 133. mid-continent North pe- tDgaea, a Ger- America. Am. Assoc. - (1984). Distribution, microfauna, and trol. Geol.Bull. 6l(7), 1045-1068. source-rock potential ilce in central of Mississippian De[e - (1980). Paleogeographyof eustatic model Phosphatic Member of Woodman Formation Pro\-ince on the for deposition of mid-continent Upper penn- :aner's (1984) sylvaniancyclothem s. Pp.l97-215 in Paleozoic I endemism di- paleogeography of the west-central united States(ed. d that Middle T. D. Fouch and E. R. Magathan). Rocky Mountain Sec.. Soc. Econ. Paleont. Ecupied by in- Mineral. mt faunas. Be- Heckel, P. H., and Baesemann,J. F. (1975). En- ton Group (Ordovician) in New york, southern vironmental ! Triassic have interpretation of conodont distri- Ontario and Quebea.N. Y. State Mus. Sci. Seru. E specieslevel, bution in Upper Pennsylyanian (Missourian) Bull. 405, l-1O5. megacyclothems ilentifications) in easternKarlsas. Am. Assoc. Petrol. Geol. Bull. 59, 486-509. t role in sup- Huckriede, R. (1958).Die Conodontender Med- princialism or irerranenTrias und ihr stratigraphischerWert. bm. Until there PaLiont.Z. 32, l4l-175. B roday on the Klapper, G., and Johnson, J. G. (1980). Ende- mism and dispersal E I doubt that ofDevonian conodonts.I Paleont. 54, 400-455. Geol.Survey, Tech. Information Ser. 14, l-:-l. Eraphic distri- Kozur, H. (1976). Paleoecologyof Triassic con- Sweet, W. C. (1979.).Conodonts and conodonr odonts and its b€aring on multielement taxon- biostratigraphy of post-Tyrone Ordovician omy. Geol.Assoc. Canada Spec. Paper 15,313- rocks of the Cincinnati Region. U. S Geol. 324. Sum.Prof,. Paper t066-G, ct--G26. Merrill, G. K. (1968).Allegheny (Pennsylvanian) - (1979). Late Ordovician conodonts and conodonts. Unpubl. Ph.D. thesis, Louisiana biostrati$aphy E (1975).Prov- of the western Midcontinent StateUniv., Baton Rouge, 184 pp. Proince. poposed nekto- Brigham YounR t-lniv. Geol. Studies Merrill, G. K., and Martin, M. D. (1976). Envi 26,45-85. Ddontophorids. ronmental control of conodont distribution in Sweet,W. C., and Bergstriim, S. M. (1974). pro- the Bond and Matoon formations (Pennsylva- vinciatism d Middle Silu- exhibited by Ordovician conodont nian, Missourian), northern lllinois. Geol faulnas.Soc. Econ. Paleont. Mineral. Spec.publ. lm New South Assoc.Canada Spec.Paper 15,243-27L t Senckenberg 2r, 189-202. Merrill, G. K., and von Bitter, P. H. (1984).Facies - (1984).Conodont provinces and biofacies and frequencies among Pennsylvanian con- of the I-ate E (1978).Late Ordovician. Geol. Soc. Am. Spec. odonts; Apparatuses and abundances. Geo,/. Paper I 96 aian history of , 69-87 . Soc.Am. Spec.Paper 196,251-261. Sweet,W. c, central Ken- C., Turco, C. A., Warner, E., Jr., and Miller, J. F. (1984).Cambrian and earliestOrdo- Wilkie, (1959). I Soc.Am. Bull. L. C. The American Upper Or- vrcran conodont evolution, biofacies,and pro- dovician Standard.I. Eden conodontsftom the vincialism. Geol.Soc. Am. Spec.Paper 196,43- Cincinnati i. (1934).Con- Region of Ohio and Kentucky. "/. 68. Paleont. euti Studies 8, 33, 1029-1068. Nicoll, R. S. (1976).The effect of Late Carbonif- yon Bitter, P. H. (1972). Environmental control erous-Early Permian glaciation on the distri- ofconodont E-246 h Index distributon in the ShawneeGroup bution of conodonts in Australia. Geol. Assoc. (Upper W. Pennsylvanian) of eastern Kansai. . Shimerand Canada Spec.Paper 15,273-278. L Pojeta, J., Ir. (1979). The Ordovician paleontol- odo[ts through ogy of Kentucky and nearby states-Introduc- nodoot provin- tion. U. ^S.Geol. Surv. Prof. Paper 1066, Al- r 196,lL-32. A.48. rt biofacies and Rhodes,F. H. T. (1952).A classificationofpenn- Aemoir 196, L- sylvanian conodont assemblages.J. Paleont. 26,886-901. trarigraphy and Sandberg,C. A., and Gutschick,R. c. (1979). graphische ' the Lexington Bedeutung.Abh. Hess.Landesamtes Guide to conodont biostratigraphyof Upper Bod.enforsch. rtral Kentucky. 3t, 1-l 66. t68. r-59. [-v and paleoe- | (Cincinnatian) 0/I

pue'DutotsolqJun-tg eql 'sluopouo3 ,{uol"uE ,(poq-Uos pu? 'ezls II IN SUETIJIJEdS ra e8pFply'qsg letusl I Jo slcolq alosnurJo seulolo^ul padeqs-uoJ^ol{3 'ed?qs eql ol sp e^?rl e,!r a3uepr^o peJlp {Iuo F punoJ ueoq Jo Ipuar?dd? pue eql qll,!\ semt"eJ rell?l eseql tuueduoc ur eql epl^ord (/86I '13 le qFurs :q9861 'ES86I : qJrq,{ 'sureP snounec.i(let€udordd" sraa (€86I) 'p le s8ltug "p la llF{Ir{) utsuoJsl^\ tuo{ uJturJads 'Ie stErrru? qtnoqqv 'suaurrJedsJnoJ IIEJo su?d rouelsod snpoDpu'd rr"unlrs eFuls e pw (986I) ls Jo 'p rrr sFssoJsnoue orll ls?ot le Jo sJpts eql Jq ol psleldJelut or? re eSpFptv pu? (€86t) le €aug ,{q pequcs gzuelc?J?qc pad"qs-A '8uI sueurroads ueunlu"N qsrllocs JnoJ eql I EIL)EJ fu"lUaUJ l?q^{ suorsserdurr -ep 'fu .IIJIBJ s{cor uI -uedo ,{lJouelsodJo souos pu" 'se^olueseJdel e^ocslp luecal Ierdar " qodoursor eql ,{"ru uerurcodsqsnlocs auoJo eqol clpqdec 0q1 Jo ,{[soru pue Joqurnu uI .aroJele seDruse tlSol roueFod oqt ur slods ll?d -orq rroql (seseqlod[q Jo) suo4?Inseds IEB JrqdEJtoeS Jo u€d {Jep Jo Y lnoq? 'Iel eql ,teqduod Surl?nl? s ur 0J? lEql sluopouoc lnoq? rrpouoJ Jo sen! Jo InJesn * m pJJeprsuot eql Surpunouns sug Jo s^?J eql eq 01 poloJfuet speJJo suos eql 'Iooq srqlJo suDd snonaJd ur 'sls?q p Jrp Suoluv -uI suo$seJdur a{IeBuuJ 'peperlp i(llouelsod ,(IpelEadeJpezrseqdue ueeq s"q sz 'puY pepunol dea{ 01 s,("/r\ |rirs paguuepl 'uoqsJo sles Fur8Jerrrsreoq pu? lurod I"np?J sll Jo {c34 lueuodur fnunlq e ol sradet 'sueurceds o^{t ur -Je sr 1r tnq '^EoloPotnour JUIluotJs luouod Ffs{sol I '^ols Jo ssel Jo Jroru u^\oqs pu? oql se ^lJeolc u" sI tI pu? 'unJ sI uo$slnJeds llJuoq Jo Enld JIel PJlaJd -ruoo lueuodurr elrsoddo eql 'eloqr\ ? s€ ueulr3eds turgul e qcns uo+ llnseJ I'su3l[rJads ?'rroJ -relur 'pue alc"J Jo lueullselur eql 01 asre^su?Jt sox? Buol Jleql qllf\ uowFceds urnteJ elesgloq,lt e qons lq8rur IEdJO JO {rO,{\ Jo leql Jo \ fFuJp ssel aJP polueuo ele qcrqA\'sluauale luopouocJo e8?lq eJuercsur lnq eslo ersqrt\ :pgJapuoli\ 0q ueq elolduroJ ue sgpnlcul sluopouooJo seRIuSB c€olorq oql uo suorurdo q lJ[[BJ?d seceJ -uress?I?Jnleu puz fpq8qs^Jl?rluosse st 3II"qd tuqu,{r ueaq e^?q lqelu urErAJ I erE su$oJc Jo 'peqo[q 'popu?dxe '3qol lnoq? {JeI I -af, E sE palaJdrelur 'ugrurceds euo Jo pug ouo +no-6Jo seulrl sralJarBqJ luopouoJ Jo drBuurns Z'8 r (m pePPequre 'opud rurrr 8'I 01 Z'l pue Suol luul et ol 0t 'sursl E aq a^Eq lsnru -u?fuo perpoq-Uos,(llu?uruop'e4quro,t''e1e6 sul"uer eql eJ" suourr$ds peJolle pus I o-$r Jo pesod -uoleJo 'eulIII luo{ loJlp seBru$" c€olorq uo pesseJdurocesoql enlq el?dJo seqq"d EF luopouoc Jo lBreulur suorsnlcuocesoq.& 'sJor{lo ,{q pezrsBqduraesoqt Sur,tlJe^o qlrA{ eJu?lsqns eurllElsdrc qslu^ioJq g' m palou sv olur oslE tnq 'uml,(qd puDxe-8uol puE lueP 'II"l e sE pe^Jeserd sr cru?8ro ,{ eultuo en4 leuel?ru -uedopur ue sB uraql tuIpJeEsJ JoJ suos?el ,(ur qcII^\ ul suorssoJduoo eJe '?Jeue3 lualeJ Furu" eql lEql IJe olur ,(luo Lou lqArsul auos epl{oJd pu" rlr pue rouol -Jrp o^u tsEel l? tuoseJder ol lqanoql pu€ s^€,r ^qeJeqt Jo 'sluopouoc Jo seFrug" c6ololq oql ot s" suor tuaragrp ur pe^ressJd q8noqlF 'sueur Ht rJPJ eql 'ln8 -urdo snor^eJd elenl?Ag pue loJ ecuePr^e eql -Jedsqsr[ocs ^DqtrF JnoJ eql'g Jetd"qC ur pelou sV P seurl leulpnlre /{er,\er ol snqt sr Jaldeqc IEUUsrql Jo uorssru 'uorlEleJdJelu ' L'a no/( 'Jo uollElncods F +:qt 're^e,t\oq JI aqJ 'dnor8 3rSolorq Joqlo eruos ol peu8lss? ErnuJruls eseql .{ll?al sr lser eql [Iv suorlco oc luelxe uI sueu ro 3o UPd pereplsuoc 'qll^\ peIW ueoq ra^eu -roedselerosrp suol lu,{ll?J5lll uI elq?le^" r -ieqf .. rnt eql Jo e^"q sluopouos eql leql Jo s?Iq f,ru saJ€qs sr sercedsgggy se ,(u?tu sEluesoJdal ol lq?noql Iru eurueJ4s 3 euofue^e l?ql uorsseJdurr0q1 e^?a[ ol llzJun 'rilr^EJ slueurele pezrl?Jeurrrr eJnlcruls plrJslfi pu? I e i(POq Jo eq plno^l lr 're^e^roH 'uinl,{qd 'IuEr lseq8lq ed"qs oqt uo aouepl\e pue :sretsnlc pssru pue " dJs irolueseur oqtJo ,{lquo rruouox4 e se dnol8 eql l?eJl 01 sI seEelqulesse ueql oJour ,{q pepl^

al. (1986)describe these features as "somites" nonmarine. The first true conodonts are from without further justification and this evidently Upper Cambrian rocks, the last from strata of figured prominently in their ultimate determi- latest Triassic age.Conodonts have been re- nation that the affinitiesof the conodontsare covered from virtually all types ofsedimentary with the chordates. rocks. and records of conspecificspecimens Also indicated with varying degreesof fidel- frorn rocks representing many diferent depo- ity on all four Scottishspecimens is a pair of sitional envionmentsare common. Especially subparallellongitudinal lines, which extend significant(to me, at least)is the fact that most bt evidence in from a point (in one specimen)not far behind conodont generaare representedsomewhere in the cephaliclobe to a point near the posterior the world in black shale deposits, which com- Fosition ofthe end of the tail. Aldridge et al. (1986)point out monly lack remainsof benthic organismsbut ndonts is pro- that theselines might represent". . . a septum in many placesinclude well-preservedspeci- d assemblages dividing the body somites longitudinally, a mensof pelagicones. r on the shape mesentery separatingcompartments of the dized elements body cavity, a major longitudinalblood vessel, 8,3 Conodontsas Ilvertebrates r4000species is a stiffeningrod or notochord,a nerve chord, I discretespeci- the gut." They note that the gut is the one of In the 130years since their first formal recog- b€ rest is really these structuresmost likely to be preserved; nition, the conodontshave been referred at one tretation. however,they alsonote that ifthe pairs oflon- time or anotherand with variousdegrees ofse- rScottish spec- gitudinal lines do representthe outlinesof the nousnessto most ofthe major phyla of inver- Ightly different gut, the fact that they extendalmost to the pos- tebrateanimals. The hypothesesrepresented by t leasttwo dif- terior end ofthe tail in two specimenssuggests many ofthesereferrals are easily dismissed, but rions in which that the animal lackeda postanalsegment, or someothers are not so readily discountedand lreserved as a true tail. should at least be mentioned in this ooinion rith overlying As noted in Chapter 2, the intemal structure polt. csecompressed of conodont elementsindicates they are com- mains of elon- posed of two parts, crown and base, which 8.3.1 Arthropodand Annelid connections l-bodied organ- must have been completelyenveloped by (or o 1.8mm wide. embeddedin) secretorytissue at least during Evenbefore Pander's original diagnosis ofcon- qreted as a ce- timesof growh. Apatite crystallitesin lamellae odontswas published in 1856,Murchison, Bar- d- bilobed,and of crowns are oriented with their prism sur- rande, and Carpenter had registered the opin- iDaturalassem- facesparallel to the direction of growth. Bases ion that the tiny fossils were the tip-ends of lt are oriented are less densely mineralized, and the frame- some parts of tlre trilobite carapace,and thus r to that of the work of organic material may be thicker. In a were arthropod, not chordate, fragments.And, site end, inter- few specimens,the basalportion may includea not long after Pander'smonograph appeared, I more or less plug of bonelike material v/ithin which Bar- Owen (1860) suggestedthat conodontsmight rs to i blunfly skov, Moskalenko,and Starostina(1982) have be analogouswith the ". . . spines,hooklets, or d setsofshort, identified structures interpreted as osteoblasts. denticles,of nakedrnolluscs or Annelids." inpressionsin- Among the other charactersthat havo been Although no one seemsto have followedup urrounding the consideredin speculationson the biologicaffin- on the interpretationof conodontelements as ities ofconodonts,I shouldalso mention their parts ofa trilobite carapace,two authors (Har- Gterior part of geographic and stratigraphic distribution and ley, 186l; Simpson,in Newberry, 1875) sug- l secrmen may the cosmopolitanoccurrence of many species gestedthat conodontelements might b€ crus- ttenorly open- in rocks representing a wide variety of sedi- tacean remains. These suggestionshave not racterize what mentary facies. Conodonts are common indig- proved particularly appealing, largely, I sus- of ar least the enousfossils in rocksthat containthe remains pect, becausethe variety of elementtypes of nens. Although of animals such as brachiopodsand echino- most natural assemblagesis not duplicatedin riately cautious derms,which areexclusively rnarine at present the array of spines that rim crustacean hrcs with the and apparently always have been. They have carapaces. ruscleblocks of been found only as reworked or redeposited Owen'ssuggestion that conodontsmight be kh. Aldridgeet specimensin rocks that might be interpreted as a group of the Annelida received seriousatten- +Ppe q sluopo -uoJ^eqceql lpql tse8ilnsosle 'suorurcads 'elnlcruls I"uJeluruI sluopouos Drul sB 'Jer{1ou? luopouocqsnlocs aql Jo sauq^eqlprxe eqlJo luec luo+ {lptueuepunJ reJrp 'splleuu?ele"qc^lod lEDprsuos ueeq -srurureJsuorlsod e^?q seleo^oJopn?curEuao Jo s,["f I$soJ oqt 'sluopmelocsleqt pe/{oqs Fonrppe Jo req Jo ernlnsl?Iuo^pru eql pue serls"Souelostur oq/( '(186I '1" 10 )lrelJ uD rellnl I ,{q pelues I.Etl ur) rollnw -,tq;o e,too:t pped eql terll pu" :s!"d [Eculetu -grd s?,r\ uoncefqo 8u{lot eJou V ,{ euJolur -ru^so,rt otur popr^rpsr plerqs oql 'eJorld eteqdsoqd urnrJpJ eleJres ot elqeun ,{ltueJed elDauuo) t t 8 I?Jo -oc?ldv eurosJo sllnp? ro ae e[ eqt reqlre -dEeJ" sp{euu€BuIAI l"ql sr uorlcafqoroferu ur lBql :stuopouoc snoJeJruoqJEJqsruocs 3 lew (euop o^?q sroqlo s?) lno palurod osP ?Joqdoc?TdY aql se gzrseurBs eql lnoq? eJ?sueJoqdoceld? eq 'stuopouoJloJ pleuus upJo JO^BJur b€ rqlJo roqlo 8ur^rTl?ql lceJ eql elr3JrnJ puz JorlII 'uos eruephe tuoJ$ raJo^trul$" ,(eql ,{la^rpeJloct?ql ^{er^ lsou TJsnllol I -ueduloc e qrns tuDsettns uI 'sueJoqdoo?ldEaql qll^\ pelsl lsnf sluournEJ?oq1 Jo uoBsns TouoJ eql PJ?E olea^oJopnEJsnoue^Jo esoql qlrrY\ uosuPduroJ -srp sq pepnlcuoc(t96I) sepoqu qtnoqlyy ItPouoJ s? elqe elr^u suorurcodssnoJoJruoqJeJ qsrllocs oql 'unlqcJo peolsur u rqiru salmrds Jo soJnleoJ,{ueut?qt Auuse8itns,(q $Isn our eq elpqdsoqd urnrol?cJo ep?u s,,\{efql!t\ + ua^e pezl$ tq8ru sluopouo3l?ql srsaqlod^qeql peArAoJ pqeuu? ue oleFlsod ol^le8Jel ,(lJorujoJ upql lF g Erq JrlEqdsoqd e^Eq (986T)Jrnf, pu? relllrJ ',(nuocertueA -Jrpssel surees snql 1I 'eqnl ro 'elc4ncl?uJelxs Ilou usJoqdoc 'peleleJ lsorrJoJe sluopouoJ eqt Jo sSolouroqortolors^qd aJe s,!\zf prleuue EXUEOJ Ol JrnC qcq^{ ot dnoJS rofeuI^lesolc aql lueseJdeJol l"ql elqrssodsurees lr 'urauo ur le"polllols snql {sant€al eql -un elE eJueqpuE al"qdsoqd qcnur IJa./\elaJcas ^lellr ere pue uJepotce cluo,fuqulaeql Jo uoq?u6p^ ('JrlruoBeJE ol peddmbelou er? $lsn our -ur ,{q uroJ surro^\eseqlJo xuA?qd pue G purotxe oql Buhrl^Ilm6olors,{qd tsolu 1?q1'(516l) uosleqcol pelsea Imonq eql JI 'soqnlJo urroJaqt uI el"qdsoqd^tr^ec 4 mw pelpnls -8ns 'qcund tnoloou)l eql uar0 s".{ l?q^r^q peppE rrJnrcpc oleJcesspqeuu? eleeqc,{lod oluos . .lou E 5 Urzue3 ls?al (186I ''p te {J?lJ ur) rollnw op sluoul 'J"e^r sua$ ,{leJeJ'Jo^o,{rog 'sulJo^\ Jo ^ioqs E :qr osl? ,(lq? -eI3luopouor seoreq.r'l?ei Jo ecuopr^eelq? Jo ..stueuodruoJ,r?f 8urdsel3,,eqJ 'qteet orul ,Jio nunotue I?U -Japrsuocaoqs i(poururoc lEql pue s,{loJ se uonrunJ lou plp l?qt slseSensstueur r qlael qloq leql pculeullu,ft ur pgBu"JJe ^eql lsorxle eJ? -ale luopouos lsoru uo^eql JD3,1d Jo {cEI aqJ ' JqordoJJruj pu? qleel relnp?r 1?q1pu? '(..snourlrqc,,)^lqEr.rE^ur 3ru?Ero 'salPJqsue^ISOUr ozuep"JeqC leql srrrJoJJe1(ol I I JreJAOJOpn"t ,{Isrnuo ere $lsn orrr Jeqlo pu" slwus Jo qleel pu? Joddneql tou pu? sJred[ErelDI luesoJder ot 4 mutapot^aq) Jelnp?J eql s?areq^{'c!.eqdsoqd oJ? slueur tueessaS"lquass? esaqlJo slueuele par?d . Fr lElnpeJ eql -ele luopouoJ teql sJlou oste JH sllJqs pod 'spqeuueeloeqc^lod Jo sesnlerpdde "E-\J.YroH'su?d -o-4setluzpunqz ur?tuoc l?qt slrsodep,(uzru A{eflueseJdeJ 01 unaoDl se8Eqtuess? luoceJ pu? t flqPoEJur al? ur punoJ lou ele sluopouor leql pue spod IrssoJur esoqlolquras seS"lquess?I€rnleu ur FopouoJ roJ /qr -oJts?t tur^rl Jo rlleol relnp?r aql Suoru?su?d slueuelo luouodurocoril Jo urJoJur uorleu? rxsal l"drcuud -retunot cl8oloqfuollllcel slueuroleluopouoc pu? 'Jequnu 'luoluoEu?lJ? IeJeueE oqJ ' I J-\erl J sE'olou Jo sod,qLsoru leqt selou 'spodoJls?EJo qteet 'qleel el?Jqaue^Jo PJrdiq .{lr^?c Fstrr leJJnq aql JelnpEleql eq lq8rur sluouela tuopoum leql dFd eql {cEI slueuelo luopouoJpue 'slueuod n eqr .ot. ,{Eol?Je tuerun8r?eql Euuetunocur'(tS6I) sepoqU -rxoo .\\?f prTouueJo osoql ol J?IrurrseJ? sluaur 's1u0urole !|II moSoFu? eq -ele luoPouoc Jo eJnFruls pu? rrrJoJerlJ . srEJedde srlEqd luopouoc ulJoJruoourEuec pu? spodols"S 'sturod tul,nolJoJ eql sepnlc lc puP rsIJIrJ 8ur^rl Jo sluellIelerelnp?r eql Jo uosu?duoc -ur fu?uiurnssrH 'splouue oJesluopouoc leql FOd Jqr Ur SOFC crSoloqfuou ssoJ8uo suorsnlcuocreqt pos?q srognc pu?'tloJs'uoqou pue I0 rzJo s,!lel^ l-qJord ur?uac urog,r,\Jo IIe'(9€61)sruoo.I pu? '(t88I) sellI?t oql uo stueururocpu? srsll (tS6I) sopoqU IrrllJds qsrlloJs '(Sr8I ',ftiaq/AeNur) es:o141,(q peuoddnssE1'{ 'selep T se p5lorfuolur 1l lnq 'stsl8olotuoepd ot PeFedd" lou -roqJ oql Euuo^?J esoqt Jo le^u ,fueruud sql 's1sn1 's1sn11oru3o^u?ru forp:orcy sequoqse8ens srqJ dnort euos go uaJq s?q ,.serlru$? luopouoJ Jo srsaqlod,{q E IESJOpeql SAZI qloel r?lnp€r eql eq lq8ru 1?gl,{lrTqrssod pqouu?,,eql 'slEe,{aqt q3norqt'peepul 'peuop ^eql Uo tuetueEueJJ? eqt pesrcroqe (9991)uo,r\O 'dno$ pqeuu" uB -u?q?ueaq e^?q ol ur00sse4rulu? pqeuu? Jo rqos 3ql Jo seu lueserdarlq8ruj sluouleleluopouoo lsql flflrq sesaqlod,tquoq,,.r's0S6I elpprur oql lllun (tS6I ! l:gtr3 puodsaJ -rssodeqt petse8ilnsaq t?ql eceldoul"s oql uI 'sepoqU:€t6I 'srognc :t€61 'ltocs '3 e) s1s6 s Jqr Jo seJnleaJ -ololuoel?dJeqto Jo tuDlurql eql peoue Fsardurr ped?qs suouJauuoJ uD)sn oI4[ 7 t 8 -nuur pu? (988I) uoqou^u?ur pw pll.rz uro{ uou

VINO(ONOJ IIHI zLl THE PHYLUM CONODONTA t7f

shapedimpressions, which are such strikine and mollusks, which have alreadybeen dis- featuresof the Scortishspecimens. mighr corl cussed,these include the lophophorata (or csed the possi- respond either to the dorso-ventralmuscle se- tentacutala) and such disparate groups of night represent ries of the Solenogastresor to the chewonlike wormlike animals as various aschelminthes, lalso raisedthe arrangementof dermal spiculesthal character- gnathostomulids,and chaetognaths.In fact, E Edular teeth izes the dorsalside ofother aplacophoranmol- about the only major invertebrate phyla that I srggestionhas lusks. Accordingto Tiltier and Cuif, features have not beensuggested as the parentalgroup blogists, but it interpreted as fin rays in the tail region of two for the conodonts are the Archaeocyathida rberry, 1875), Scottish specimensmight alsobe duplicatedin (which were largely or entirely extinct before 5). all of whom prochaetodermatids certarn by very long sp! conodontsappeared), and the porifera, Bry- rs morphologic culesin the posteriorregion. ozoa,Echinodermata, and Hemichordata. rents of living Tillier and Cuif further suggestthat the ce- Lindstriim (1973) and Conway-Morris irm conodont phalic apparatusofthe Scottishconodonts may (1976) have either directly or indirectly sug- be analogousin arrangementand errenrn mrn- gested that conodonts might be an extinct the argument 3 eralogyto the radular teeth and, particularly, group of the invertebrate superphylum termed be the radular the buccalmandibles ofthe Aplacophora.They Irphophorata or Tenkculata by various au- : most types of note,as I havein a previousparagraph, that the thors and composedat presentof the phyla Dlogic counter- principal reasonfor rejecting a rnolluscan affin- Brachiopoda,Bryozoa, and phoronida. Con- f living gastro- ity for conodontsis the argumentthat mollusks way-Morris's suggestionis based on his inter- not found in are incapable of secretingphosphatic hard pretation of a curious little fossil from the fa- mdanl gastro- parts. However,Tillier and Cuifhave subjected mous Middle Cambrian Burgess Shale of : conodont ele- the radular teeth and buccal mandibles of British Columbia as a vagrant tophophorate, E the radular Chevrodermaturnerae (a prochaetodermatid and on his interpretationofimpressions in the rts are entirely caudofoveate) to both X-ray microdiffraction supposedlophophore of that oryamsmas con- t radular teeth and microprobeanalysis and have discovered odont elements.Unfortunately, the conicalele- in sl mmetrical that both teethand mandiblesinclude substan- mentssupposed to havesupported lobes ofthe $ow consider- tial amountsofcalcium phosphate,as is prob- lophophore of the creature Conway-Morris r conodont ele- ably also the casewith the radular teeth of at named. Odontogiphus omalius have all been ft et at., l98l) least certain scaphopods.(Gastropod radulae dissolvedaway, and the fossilis from rocksfar lrt punch,sug- studied thus far seemto lack phosphate,and older than thoseyielding the oldestspecimens Et most living the external spiculesof the Aplacophoraare I would regardas conodonts.Thus, in addition to Fologically aragonitic.) to questioningthe realsignificance ofa vagrant, d henceare un- just The features summarizedled Tillier and or swrmming,lophophorate, I disqualifyOdon- toup to which Cuif to commentthat if conodontswere apla- togriphusas a seious contributor to our under- Ed- cophoranmollusks, it would be normal for the standingof conodontaffi nities. if (1986)haye phosphatic buccalmandibles, at least,to be fos- Lindstrijm (1973), on the other hand, rodonts might silized even though the aragonitic dermal pointedout featuresthat suggestconodont ele- lrn-t featuresof spiculesmight recrystallizeand be unrecogniz- ments were internal (not external)structures; rcimens invite able as conodontelements. They thereforere- noted a generaltendency in the evolution of f caudofoYeate gard the Conodontaas a potentialclass of the conodonB toward an increasein surfacearea of rh a compari- Mollusca, most closelyrelated to one or an- elements;and suggestedthat pits in the upper hm that living otherofthe groupsincluded in the paraphyletic surfacesof certain conodont elementsmight oe size as the Aplacophora. have been the sites of muscle attachment. hts: that in Theseobservations led him to suggestthat con- some Aplaco- odont elementsmight have servedas intemal I inro two syrn- E.3-3 Connectionswith otherinvertebrates supportsfor a muscle-operatedtentacular ap- I grooveofliv- (in Miiller Clark et al., l98l) lists a largenum- paratus, or lophophore, and this led to the fur- :nral suture of ber ofadditional invertebrategroups that have ther suggestionthat itions reminis- beenconsidered appropriate, for one r€asonor ttish conodont another,as taxonomicreceptacles for the con- anceslors of the co[odont stock and those I ttrechevron- odonts. of the bra- In addition to the arthropods,annelids, chiopod stock were closely related at some relatively late IJPJ pue 'epuEJ ernpruls ul rqrluopr J?eupu" uo4nq -uoc laql petsetilns oslBe^eq sJoqln" Jo I"IUelul lera^es. i rnq '4"proqc -lrlslp ur se4uelrulrs a,{rlcflll? elrdsop 'er{l?ua 'p01csl0J ^Ir lopouoJ eql 8ul -oF?qJ eql ol sluoPouos ar$ turuSrsss qlr,y' -J"ruurns ool 0q louu?c uoucrulsuorer s.rug4s lfp Japu?d urrq 'Je^e,{roq 'surolqoJd snoJournu eJp eloql -purl os ,,'4Jr,, Jeql?Josl? q suaurcadsqsn El JSnPJeq ouj 'slooJ.sluopouoc -locs er0JoseJnleal oruosJo uoqqsJtuolur leql trlNe Jo dnoJa 091peJe^ocsp p"q a^r leql Pepnlcuoc Jeld?rIJsrql ur JaIEIpalou eq ,rr lr'Je e,'{'oH Ed 'susd pffq ',(pn$ lu?Eolo^[l"ug s,rjlsla?ru?zs Jo aiu?Jeod 'el?Joqaloqdol u^{oDI ,{uB rj"r{l uouezruea :d'qduEououl -d"^ueur ogl qll.{ 'puy 'sluopouoJueruo^oq pu? -Jo ur luoJeiglp,fia^ sleurrueJo dnorE e elecrp l{f IssoJ qlr^{ uerchopJoJo uollnqulslp aqt ur pJ^raJrado^\ -m plno,t\ (flo^rlosdsor 'suu lepnsJ pue seurol I B trr suoudu3s selleruoueureuec urcIdxe ol loporu E turplrnq -o/(ru s" ''A e) peloJfuolur Jr 'qcq^\ |IIrr 'sluopouoc ur dnoJE teql Jo uounqulsrp puD slrqeq eql '(sug peuoddns-^eJ :seJnlcn4s^lloaloc psd?qs-uor r rsJg aql Popr^ pesnpeq I pue uoppes afuoeo IL6l ur esnsJ -Aeqc'palEeder ' t'e) sreqloepnlcur pue oJoqd r 1998I ) rePued -oq ?ql?u8oleEqJ erD Jo se^qEIaJ crozosal^l -oqdol E se loJfuelur plno,r I lEql em1"eJ{ue pu" orozoeledoq ol lno urnl lgftur sluopo {cel suoruoodsesoql '€86I Irlun pequcsaplou 3do a\J I r'8 -uo3^lJee orll lsql eql 01 petce4le oJel\ rlJJqr'['suorsseJduJru"unur€N qsrllocs -cru?d sEA\I'ql?utole"qo ^llrqrssod tur^ll E'(JI'8 ^lJeln'trC) 3ql Jo senleoJ qlw\ psrBnbs eq ()1 speeu seJnl $se reql qcq,t ,llr3rs Jo sourdsEurds?rA eqt pue (npotbtotld -?eJosoql uro{J PecnPepaq tepou, p:r1aq1od El ol lsaJelurJo ol peuErsse,rou) slueurelarrsoJruoc uelsr^ -^r{ eqr r"ql luaruluoc ot lsJg eql oq 'pedsns I uPau ro ur luou] -opro ,{ll?e puE uElrqureJ alel ulzuec uee.t\t 'plno^rlnq'€t6I ur u^lou){sluopouocJo soJnl r p{rB 'sl.uopuoc -eq eJnlorulsuI,qu?[Iu]rs EuDtuls E paleJls -?oJIIe lunocce olur {ool ,{llnJor"J urolspurT €eJ pusls lllru -uoursp (286 rlls.{rau?zs ueqa oroqc I ) Jo 'gJI qSnoJql cluoD{ueld peurEruel sluopo .neJ e ,(IuO fuoEeleceq1 arueceq dno€ pet"losr i(lpc Fs -uoc lsoul seeleqa'ol$sos eueceq'e8qs pArel truol -rSoloozsql pue 'eqleuEoFeqJ^Ueuq unl,(qd oqtJo -ryqd e .roge 'spodorqcBrq eql esn"Joq ps^lo,{e socuoJoJ rropouoJ t'8 suuol{ ,adoJJeSurlr ol pelqar eq lqtur sluopo -JIp IsluetuBpury aql lEql pu? 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VJNOOONOJ IIHI tLl THE PHYLUM CONODONTA lls Phakelodusand, Sagia4 elements. ,,. I am not c€r_ rmens and concluded that they were . . frag_ tain that any oftheseproblems is fatal, but thev ments of the hard, crustaceousends of the all diclate caurion. For example. graspin! the segmentsof some trilobite.,, In apparentdef_ spinesofall living chaetognaths areentirely or_ erence to that opilrion, which he did not at_ ganic in composition, whereas all specirnens tempt to refute, Pander remarked somewhat that I regardas skeletalelements ... ofconodonts wistfully that (my translation) . . Complete are thoroughly phosphatized.Furthermore, al_ conviclion that theseremains are really teeih of thoughBengtson (1976) has outlined the steDs extinct fishescould be reachedonly if similar by which the transition from organismswiih structures could be demonstrated in living elements phakelodus an_ like those of to those with imals of the sarneclass." elements with the internal structure of all known conodontsmight havebeen made, that transition has not yet been objectivelydocu_ E.4.2 Newberry,Hinde, Huxley and Myxine mented.Thus it is my perhapsultraconserya_ Newberry (1875), on his own account. and trye conclusion that phakelodus and other or_ Hinde (18?9).on the adviceof Huxlev.con- gamsms with skeletal elements of similar cludedapparently from shapeand lusteralone lntemal structure(the paraconodontida of the that the conodont elements they examined Treatise classjfic.ation)are not conodonts. If were so closely similar to the teeth of the hae_ that is the case,then identity in structureof frsh,Myxine (Fig.8.2).as to be indistinsuisha- Phakelodus and Sagi a elements has no bear_ ble. In fact. Huxley is reported ro have in_ lng on the question of conodont affinities. frata- (A) Bran- althoughit may suggesrthal rootsoflhe Chae_ Erioe (Rhyncho- tognathaare to be found in the paraconodon_ E {B) atrd(C) re- Fig. 8.2.. Myxine glutinosa, a hagish (o, slime eel), tida, a goup formerly assignedto the Cono_ reprcsents the chordate division to which many believ; donta on the basis of gross conodonts to be mosl closely related. Redrawn from morphology of Miiller (1836). skeletalelements.

3 aITOWWOrInS d this zoologi- 8.4 Conodontsas Chordates E the category Only a few studentsofconodonts haye taken a 1982) demon- firm stand regarding the biologic affinities of r structure be- condonls.and most of them favor an assign_ d early Ordo- ment rn or nearthe phylum Chordata.It is thus r assigned to ofinterest to look criticaltyat the evidenceon tEs of Sagitta which that assignmenthas been based. L I s'as partic- t tbat the con- pander EDic and early 8.4.1 Theopinions of Eognalha be- Pander(1856), who coinedthe nameand pro_ d I had used vided the first diagnosesand descriptioni of thar group in conodonts,included those diagnosesand de_ lin anomalies scnptrons rn a monogaph that dealt Drimarilv dOrdovician with fossil 0shes. Throughout rhai pioneei srrh the , ap- monograph,Pander treated conodontsas the t study, many hard parts, possiblythe teeth and jaws, of a lscovered the group of extinct fisbes, prirnarily, it seemsto me becausethat is what they looked like to rs. however, him. Panderdid not seriouslyconsider assign_ t rle Chaeto- rng the conodonts to any group other lhan the irbs in distri- Chordata, but he noted that Murchison, Bar_ d structure of rande,and Carpenterhad examinedsome sDec_ JEDrr€^p? osoql i(ueur prp I s? pue) Jorlreo sJee,{,r\eJ e euop eJ? suorsnlsuocasoql 'snoeuoueJo elq?uoq rruc p3Isepnts p?q Ir.D{ se 'ro^e.{oq 'elou prp poluos -sonbJeqlro sr l(llu$e luopouoJ uo suorsnlJ I)Jl Sr 1I Eql"u -eJd Je^au seA\ qolr{.r 'ecuepl^e^oql o^rsnpuoc -uoc s.ou?lJqc?trAlJoJ srseq 1enpe3 aW q?noqr :FPutrsse sel?p r^?rl ol pJrur"lc pue sJqsSJ^nruud Jo qleel ue^e leq1 're^eMoq'eloN sl"rurue eseql JoJ Sluopouoc Jql se sluJurJle luopouoJ Jo uorlqaJfuJlul pesodoJddnor€ Jueuot"Jdnslslg eql 'sluopo E-I{ SSOrC'enssq eql ur perjncuoc (€€6I) Iqew puE uosu"Jg -uoo roJ ,fuo8olecdnoJE-JepJo uE Jo luauqsq t rnoqe uorlBsg 'suleurar el?Jqeue^ eJa^\sueurcods oql l"ql -q?tse prrrJoJ eql eq uo4nquluoc elq?Jo !f,!q-{ 'uololels pu? euoq oJe,rsal?Id IBs?q oql t?ql sJoqln€oJ -rueuJlsour S.au?IJEJO?IAI^"ur '!oqs uJ 'euueuuou fuoJ ,{oq1 ela,r sq pu? 01 pelse88ns'sls?lsoelso pue ers,t\oqo Pu?{JoA ur pepouocuoeq p?q ro qleel ^olsJ?g ^\eN ry 3r{1 'se!{coelso'slsElqoelso ol pue ozrs sluopouocq3rq,r uro{ salsqslc"lq u?ruo^eo lql f,Juepguoc ur puodsauoc ol reodd? ^SoloqdJorrrleql semtcruts qt!.{r eql l"ql poless?oslE eq 1"q1tupou ,{q peseeJc ssoJc es?c raqletol 'sess?uroseqJ 'euolspues Surpr"H -ur lou s sorlrulu?luopouoc Jo lueussess? EprrPd-.i se ',lueut aql ur peluesoJdsJosl" sr l?ql s.ausIrsJsEIAIuI ecuopguoc 'snourlrgs er" r4lel :rrq /neuJo st|.ue?e'snpoapJ ^nu?punq? 01 peu8lss?sluellIola IeJe es oql seeJeq,,\a'snoeJ?cl?J eJ? JerrrroJ oql leql se,ra .Eqt- 01 Ieuolelu Jo selEldles?q eql uI sessEur peq os qleeleuolsolc,{c pu? sluopouocuee^\leq pelou lIsnrtr sluetxela -ep (286I) eullsor?ls pue 'o]uoplsol^I^8uods '^ols oJusrsgrp,{Iuo eqt pue 'qy{\oJaJooporrr ro 5rn1 rfuBIJE eql ulo{ -J"g 'Jelel sJ?e^,{uEur 'reAeA{oH sluopouoc -Jruls IEuJJlurlnoqE peuollueu se,r AurqloN rytnu Dutpo4 IJPJpntJur ol uolsnlsuoJs[{l pualxe01 Surltr/$ 'qFet ,{ardruq pue qsgteq ;o s8ul,{r?JppezrTe Tr)s urql paJEd -un selyreq 1nq 'srrrJopocsJlsoJo su?d qlnoul -:auat f1-relrurs qlr^\ dJeq,'aeN pu? apurH ,4q IrsqJ euuuop uesq e^eq 1q3[u sluetuele luopouoJ eu]os sJsdeduro{ pecz.rtstueluele tuopouoc Jo s8ur q plnor ! teql leql uorurdoeql ol urx pel suou"^resqoeseql -^\sJp eurt epruc SuueduroJ ,tq pel?leJ .{lesolc FduloJ tou eJe 'euoq urJopoceJlso pol?rcoss? eql 01 relsnl eJe^\(s^erdurel pu? seqsg8?q''a'r) sorfiolsolo^t rraJp luzuod pue rolot ur J"lrur$ peJseddet?ql atuqsqns B pu? sluopouocl€ql uorsnlcuocsq pouoddns Ep{trs 3'(ts6l) ol es?qeql le peq3El13erc,{\ sluetuele luoPouot euelJ?JcEt\l'(seluoz,{urorladrepro) s^erdruel IXI lueJeJ Pu? eqlJo euos leql p01ouoslB aH opeloloJ [Erl puE (seprouu^II ropro) soqsgt?qaqt pet€8e r Pegruepr -uecJoeuolspu?s EurpJsH uerchopJo atpprl l -IeJosle eq qcrq/rrot (?t?urepocq?I eqt) fro8 F Perurod^oql pue aro uI srrrJepocs4sou^{ou)lllea erll qlr.!\ Jncco -el?c e^rsueqeJdurocaJour E ol peu8rssss?A\ fuor pcnueqc slueureletuopouoc tEql paUoder(6261) Irr,) q3rq,{r'seluopouoJ ropJo ue ur raqleSolsluopo lol dn peleelt eql podnoJ8'slueuruoJr^uo Jel?aq${ uI p!D|t2tu -uoc r lt-f6l ) uosrtlE (SI '3lC) (?lemoqcu^qu) srrrror u?euruoru tuoq psoqIo uouoratdtautpuD tua^oJste g r'g 8 [xo+ pe^lo^a sel"rqeue^ aql /(oqs ol pltu?) 9 r'g -eu l"ql pepuoturIooq snounc? uI '(€Z6I) euelJ-eJ3sl,il 'repu?d[q poJopuodpup pequcs EBJUn aq s^err Felepur Je^o uolpauuoJ -0P eJnpruls uJ secuoJeJrp uDautuawauaqt puD auoUDlJpW F'r'8 E puE 'oluele{ lEruelur lsrlu?ls eqt ,{u? ocuopr leql -qns Jo lunocc" {ool legl t P€qursep 'osounry8 ^eql r ,(lqrssod -^a ou pug u?cI auut7r[ 'qsutur{eqr -ieqr ilnJer?cos uooqp?q l?ql plnold ruorlducs Jo qleJreql pup 'sueqsJo soletdpulep pup lnJF 'rErlrureJse^\ eq qJrq^\qll/( ^eFnH qsgJeqlo ro qleel eqt 'sluelueleluopouoc SuorrJ? ed?qs pu ItEJo JJuepI^a (auqtl I) seqsgg9\Jo esoql ellun /(lr?elc^uP ero^\ -relxe ur ,bu?Irurs ssoJt 3 Jo esnsceq(,{lejrlua I ssr?ololuoel 13ql slueuela luopouoc ur sernlcruls puJel lou Jr) ,(F?urud uorsnlcuocslql peqrEer 3JO UOISnICUOC -ur poqucsapJepu"d 'oslv 'cru"fuo oJ? l?rll 'Jo^o.!\oq'J?op sr 1I dnoJEeul"s eqlJo^eql II? r Jlqereprsuoc qsgaeqJoesoql seeJoq l'r4?qdsoqd ^lejuue ar?sluopo ,(lu?sseceulou 'seqsga^rlrrrrrJd Jo sat"ld pru furqtiue ruo:g -uorJo sluelueleeql 'esmocJo'pue :(gt'8 puP D -rep pu" ql.eeleql eJ?sluopouos leql .Jerteq,, PrqJ4l? 3r? 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YINOCONO] EHJ 911 THE PHYLUM CONODONTA t't7 ber ditrerent yearslater), that many ofthe elementsthey col- Ulrich and Bassleron little evidence on con- other than lErs lected from the Middle Ordovician Hardins comparativegross morphology. 1986). SandsloneoIcentral Colorado were attached ai the baseto a substancethat ".. . appearsbony but does not have the structureof ordinary 8.4.7 Interpretationsof the Scottish kr bone." Bransonand Mehl's (1933) comment Carb onife rous s pec i mens ". rpressed the that . . the materialsto which the conodonts The most recentdiscussions ofconodont amn- are ah and der- attachedcould not be from annelids or ities (Briggser al., t983; Aldridge er al., 1986) from I necessarily anlthing but vertebrates..." takes on are concemedprimarily with appropriate inter- osever, that considerableimportance becauseit was the pretation of the four Scottish Carboniferous conclusion pair nrily (if not of a of trained vertebratepa- specimens,to which I have alreadymade re- leontologists; riS' in exter- but it can hardly be acceptedas peatedreference. Briggs et al. comparedthe evidence s the teeth ofaffinity in the absenceoffurther de- first-discoveredand best-preservedScottish the teeth of scription, illustration, or histologic analysis. specimen with the cephalochord.ateBranchio- Possibly n frnd no ev- they werereferring to materialsuch as stoma(FiE.8.lA),the ammocoetelarva of lam- I of the sub- that describedfrom Siberiaby Barskov,Mos- preys, and arTowworms of the invertebrate kalenko, (1982), lructure de- and Starostina but this will al- phylum Chaetognarha(Fig. 8.lC). Their con- waysbe il by Pander. uncertain. clusionwas that neithera chordatenor a chae- tognath model ". . . provides a satisfactory an- question 8.4.6 Compositionand growth of etements swerto the ofconodont amnity." basalbony Following description of three additional d Ellison (1944), and Hassand Lindberg(1948) specimensin 1986,however, Aldridge and his cleared up long-standingconfusion about the colleaguesconcluded that conodontsrepresent rt elements chemical composition of conodont elements a group ofjawless,craniate chordates seDarate rbrns in the pointed and out that the phosphaticminerals from previouslydescribed groups but perhaps lone of cen- they identified were the same as those in fossil rnost closelyrelated to the hagfishes(Myxino- some of the and recent bones and teeth. However, Gross idea). A similar conclusionis expressed,but |t tbe baseto (1954), a studentoffossil fishes,made the im- just in passing,by Jeferies(1986), who notes in color and portant determination ..s" that conodontelements that the hypotheticalanimal he proposesas derm bone. are not composed of dentineand lack features the first "crown vertebrate,,resembles the Scot- @inion that that could be interpretedas either a purpa or tish Carboniferousconodont animal described have been dentine channels. Furthermore, Gross pre- by Briggset al. (1983).However, in the nearly : he was un- paredthin sectionsofthe Pa elemenlsof Ozar- three pagesJetreries devotes to listing the char- Dinclude all kodina (Pander) murchisonl and determined actersof this hypotheticalcreature, I find onlv r later, Bar- frorn the arrangementoftheir lamellaethat the six that might be more or lessobjectively 1 (1982)de- rep- elementsmust havegrown by accretionofnew resentedin (or by) the Scottishspecimens (ma- el ptatesof material to their outer surfaces,not by addition rine habitat, eel-shapedbody, head-trunk-tail, drs- a genus ofnew lamellaeon the inner surfaceofthe ele- rasprngtee1h, ?lensless paired dy in the eyes,?somites). I ment, as Pander(1856) had concludedwas the suggestthat, as Jefferiesintimates, rs together the resem- case.Gross vr'asthus able to assert with some blance betweenhypothetical animal ..s,'and rrespond in confidence that conodont elementswere not the Scottishconodonts may be so striking be- I Osreocyres, the teeth or derrnal scalesof vertebrates.nor cause the latter were used as a general tov and his model werethey componentsof the vertebrateendo- for the former. rE bone and skeleton, which should show evidenceof ossi- In reachingtheir conclusionson conodontaf- I remalns. fication about a core of spongy, cartilagenous finities, Aldridge er al. (1986) and Jefferies rred in the tissue. Grossconcluded from his studiesthat (1986) clearly identiry with Pander, Huxley, tqts as the conodonts primarily were soft-bodied chor_ Newberry,Macfarlane, and Ulrich and Bassler, r€d to have datesassignable to a distinct branchofthe Ae- althoughtheir reasoningis somewhatdifferent. never pre- natha. lt is ironic. I suppose,that his detail; Becausethe Scottishspecirnens lack any evi- 6 Kirk had studiesled Grossto conclusionsvery similar to denceofjaws or a bony skeleton,it is the opin- I did many those advancedby Huxley, Macfarlane,and ion of Aldridgeand his coauthon that 8Ll lrF Jo arnlelnasnrrr !O rrq8F) perrerler ttla.if '['8 '3lf,

I pe,\oo-6 eql ur +sjapun pslaa{ ilJo au?Jqr[eu lp uorlJgsssoJc bll e sr qcrq,{ luEs e 01poqrel r Isntull eqJ E'|sod puE plerr uersls sdo^tau tettuaz o JEql Jo sacrd" Wu raddn '€'8 &q eqr ueql[ {i rEpeurofpu" E ,iuJoq 'u^\oJq nI Isqpnlfuol lDqlre uo eu?Jq tlvld lvsv8 g '-ilLrRJ IElo aql :t-tvld -rvlillo ;tr Jrpqdoc oqr lrlEalu snotnur I qDrls 'pesserd lEEd Jo eleld tFB uorl$od ur lFrrertp f1p:e,t' ls a.roqY sluau dtf Jo arnpn4s l furpromy selc lDddns Jo tueur Fraq3s opr^oJd : JSrJ^SU"I PUe :!, puE (e^oqE FBool aql ^\oqs nnry3 aufftl,tt prm g g e:n8rg

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! g sepEirBqc slr IlD $rg eql ..'s,, farJ-grf Jo ernl ,!:edrssP Jalsseg E+iaN'.talxnH qP sr sTql ocurs 'lecrue^ I qr i8,., e qrns t |trq tsar le uoq^{ llr El " seqsgS€q aEcrea-d eql saoqs IEaJ 4epjoqc eql THE PHYLUM CONODONTA 179

the chordate feature to which the conodont appamtus basal plate, which supports the floor of the shows the greatest similarity is the lingual structure of mouth and is the rigid, immovable site of at_ hagfishes. . . in which the rows ofteeth are not opposed tachmentofthe jaw muscles. when at resl, but are evefted by protractor muscles in such a way thal the action is bilateral rather than Contraction of prolractor muscles attached, vertical. to its anterior end causesthe dental plate to slide forward in the grooved upper surface of Sincethis is alsothe chordatefeature to which the basalplate. As it doesso, its sidesflatten Huxley, Newberry, Macfarlane, and Ulrich and and the rows of lingual teeth above it are Basslerassigned conodont elements, and a fea- raised, spread laterally, and eyerted from the ture of Jeferies' (1986) hypothetical animal mouth (Fig. 8.3, upper left). Dawson (1963) "s," the first cro\ln vertebrate, a briefreyiew of likensthis sequenceofevents to the openingof its charactersis in order. a book. Contractionofmuscles attached to the posteriorend of the dental plate efects retrac- tion plate, 8.4.8 The lingual apparatusofVyxine of the closingof the book, and ap- proximation of the teeth in a graspingmove_ Figure8.3 includes ventral viewsofthe headof ment. Repeatedprotraction and retraction of Myxine glutinosa, a typical hagfish, drawn to the lingual apparatus altemately spreads and show the toothed lingual structure everted (left, approximatesthe rows of teethand is effective above) (right, and retracted above).The sagittal in tearing food and conducting it into the and transverse sections below these two views mouth. During theseripping motions,the lone provide schematicinformation on the anange- palatal tooth may serve as a gaff by impaling ment of plates supporting and principal rnus- chunksof foodstuffand therebykeeping them cles.According to Dawson(1963), the lingual from slippingout ofthe mouth during prorrac- slructule of Myxine has four primary compo- tive moyementsofthe dentalplate. nents. Above the mouth there is a single, back- Individual lingual teeth of Myxine glutinosa wardly palatal directed tooth,which is median (Fig. 8.4A) are complexstructures made up of in position and firmly attachedto an overlying an outer horn cap separatedby an epithelial plate palatal of cartilage. The laterally com- layer from an inner conethat includesdistinc- pressed, slitlike mouth is flanked by flaps of tive, goblet-shapedpokal cells.In the centerof mucous membrane,which arecontinuations of each tooth is a mesodermalpulp cavity. The the cephalic epidermisand fold into and line base of the outer horny cap is embeddedin a the oral cavity.Embedded in the mucousmem- groove in the mucous membraneof the oral brane on either side of the oral cavity are two cavlty, exceptlaterally, where it joins adjacent longitudinal rows of sevento nine yellowish- teeth. Dawson (1963) notes that severalau- brown, horny teeth,which areconical in shape thors believe that growth of the horn cap takes and joined at their basesto form a tooth comb- place by cell division and keratinization in this When the lingual apparatus is retracted (Fig. basalgroove. Cells in the epithelial layer be- 8.3, upper right), the tooth combslie flat, and tweenthe apexofthe horn cap and that ofthe apices of their componentdenticles point in- inner pokal-cell cone appear pl/.led.apart, as if ward and posteriorly. they had been stretchedbetween a horn cap The lingual teeth of Myxine are firmly at- that gIew more rapidly than the underlying tached to a cartilaginols dental plate (FiE. 8.3), pokal-cellcone. The latter,composed ofwhite, which is a troughlike structure of V-shaped opaque,resilient ectodermal cells, is peculiarto just crosssection that lies below the mucous the Myxinoidea and surroundsa small pulp, membrane of the oral cavity. Its longitudinally which contains blood vesselsand nerve fibers. keeled underside moves forward and backward Various authors have speculatedthat the in the grooved upper surfaceof a cartilaginous pokal-cellcone might be a replacementtooth,

Fig.8.3.. glutrroJa. .Myxine Top two views show venrral side of head,with lingual apparatusextended (left) and retracted (dght). central and bottom figures -of are tralsverse and sagittal sections' t}re rieao to strow erem'enti a.J musculatureofthe lingual apparatus.Rledrawn from oa*son fts65i_ lJO JUO PeJeprS -epul pedole^ep uaeq e^eq lqalllJ sed,{l eseql pue qs41o3saql'Je^e \oH'u^\oqs e^erl(186I) F[l JSUfunS OU Jo sosnlprEddeleql Euncedsnsul (€961) 'le 1e qlrus pue (t86I) sfflug pue'fqrolq ?!InEotsoql?ua uos/(ieq^ueJo urof l (elnpEr u?tsn oul 3ql pu€ s^aJd 'qtrrus 'eApupIV se 'stuopouoc Jo snleJ?d dorqu? 's{snl -urel D1p) SurdseJlno-pue-ul pu? :(arlrxtl4J el?) -d? ortEqdeceq1 Jo uoDzlejfuotur'pclueqceru punoJ Elsrp ur Surdsert l"ret€l :AuI^leqJ u^loppuE-dn-PooJ Jo'IBuorlounJJoJ Iepour SurnErIuI u? 'poap rn :l?pJoq3 ol lsoEur ,(ys1zrur11n pu? 'dser 'peJqs 'J?el ol -ul 'q aulxtw Jo sv ?Jedd?IEnSuI oql Jo uoD3" IuoqJ Jo sdnoJS peu?rsapsqeJ?ddE l?cJnq D ur uorlc? Jo sad,{l turdsErA eprs-ot-oprser{I socqlns Jotno JI3q1 FroJ esoql ol ,(le{I aelql ,{[uo oJ? areql'esJnmJo JerlunC ol JsltaLuE[ pezllEJSuluJ J^ISSJJJnSJO UOl',tlSOd r strf{ooq tuol?I 'st?Iluec s" Palelfuel -d? fq ,(uoEoluoSuunp peBJelue osl? pus pezrl Itr qll.r\ stuslu?E -ur eq lqAru leql uoISeJ peoq eql ur Buql^ue -uelcs fllnols eJe^rqcrqnd 'slueuele luopouoc I IEqt ssdEqsaql se^reserd sueurceds snoJeJruoqJ"J qs4locs elelduroc rII u?dJolunoJ ou sr oJeql 'aulxtJ;\[Jo 4 -ipoq FuruE oql Jo pelreseJd lsoq aql Jou uaurlreds ueu qleol Fntul eql uI euocllac-p{od eqlJo ocu?cr 4'r I ew pu? -nlrs u?3uetllY eql Jeqlou 1nq 'snouaSelq:zc -Jrufisoql re^elEq,t\'lueurdolo^eP Jo ePouruI dsE-€ 'qteet lerll ueeq o^eq pFoqs r{c[q/'\ 's^?l ug s? pelartual ',{IqeunseJd 'pu? arnpruls I?uJelur uI secueJeJ I Dadsaj qlr^\ -ur ueeqe^eq leq/(Jo puJ rouolsod 3ql t? suors -Jrp snolrqo pue punoJoJdor? aJeql lualrlelo 'Jnegdsoqd -seJdrrrr a^rasard sueulcods qslllocs aql Jo o.{! luopouoc uroJluoc e qTlt^Dsou\ry8 autxth[ '31{ a uEJoqdocBlde 'sr l?qJ Jeqlre 'uou?AresoJdJo sepnlrssrol^aql Jo qlool IEnEurt? er?dtuoo I t'8 uI 4l (986I) Jtr\) ol lsnf elq4nql4l? sr stt{l 1?q1oJns os lou Iue .,'oJIIJoepour cDrs"ftd e ot uo-rleld?pepn fI)ar eql 'pJ?EoJ I'aulxtw ur uoqcunJ sntEEdde oql e)pul ol -pr^rpurue ar?feqllpqlpu? qte peulcpc pue E,JOUOD?lntIlnC porrnbar er" tEql saleld I€s€q pue 'IEluep 'l?13 qleel osoql uee^feq uoqJeuuocapeueSol^qd ' ' ',, rr) u:aq lou s?q qed snourSelpec eqlJo ec"Jl ,(u? {c?l '1?Jsnql ou sl ereqtl?ql,{lql lsolu sI lI l"ql8upou I arotu tuql(u? pelJelloc sluopouoo pe^Jasard,(lelaldllIoclsotu Kq qlp,etauutw lo uorssncslpJsq sezueulums { pu? uropSupl eql aJ? qcq^{ 'suoruroeds u?unlrs uecueruY (€96I) uos^\Bc'ur€uecIIE l3 lou sl sql lnq ! |K) ngzrl"JSurru qou ueeq seq DJedsar qlr^\ 1I/6I) rurE€oNpu" rollntrl ruoJd uonceslEulpnl€uol uI osl"'luopouoo eJo (g) (uo{ uoqces austtll rllool (V) 't'8't!d lP Pue auutrl,,[ lueuela urroJruoclecrd^J 1€961)uos.rec l€ulpnrlFuolldl Jo FnBurI r sluopouoc Jo v I UOBJUNJJO &I Du.tots Art^s? dlnd iroJ'dtur'--) saruolo^ur If{ 'sueunads ; Jo JI?q rouel -oor\eq3 0gl (t) tg Jsoql s? qcns rr_ opro uEueq IIInL$ aJUSSaJd Fqnl .{eql leql esoJnut teJo- E Jo sadEqseql Pfurrll aql pu" dEoJ I?truroq3 rtpouoJ JoJ serl D#ns ol stoql I 'ijeurums uI e!rru4Io lmuutns 6 r'g rrqP qJnu fus^ nujs lPcrueqc b"u .(nuopuod

VJNOCONOJ IIHJ 08r THE PHYLUM CONODONTA l8l pendently many times. If so, similarity in me- the repositoryfor the Conodontaor its sister chanical action, even if real, may not imply group. very much about biologicafiniries. Without in any way minimizing the possible signilicance of the bonelike features reported by Barskov, Moskalenko, and Starostina 8.4.9 Summaryoffeaturcs indicating chordate qlfinities (1982)from the basalplate of severalMiddle Ordovicianelernents from Siberia,it shouldbe In summary. evidencetaken by previous au- notedthat no suchfeatures were noted in corn- thors to suggestchordate (or vertebrate) affiri- parableparts of any of the conodontelemeqts ties for conodontsconsists of (l) similarity in studiedby owig (195t), Gross(1954), Miiller chemical composition of conodont elements and Nogami(1971), or in the closelysimilar ele- yertebrates; and the mineralizedtissues of (2) ments of ArchaeognathusrccEntly analyzed in the shapesofconodont elements, which suggest detail by Klapper and Bergstrtim(1984). The that they functionedas teeth or jaws; (3) the affinities of Coleodus, to which the Siberian presence within the basalplates of severalSi- specimenshave been assigned,are unknown berian Ordovician specimens of structures amongconodonts; and the Siberianfossils are suchas those that characterizevertebrate bone; diferent enough from the tlpe of Coleodusto (4) tlte chevron-shapedimpressions in the pos- raiseat leastmodest doubt about their identi- terior half of seyeral Scottish Carboniferous lication.In short,the featuresnoted by Barskov specimens,which have beeninterpreted to be and his coauthorsmay indicatethat the basal myotomescomparable to those of Branchio- platesof the specimensin which they found (:Amphiorus); stoma and (5) imptied similar- them are bone.But it is not entirelyclear that ity of function betweenlhe cephalic apparatus the specimensare conodont elements!Nor of conodonts and the lingual apparatusof have those featuresbeen seen in the basal lconiform element Myxine and.other hagfishes. platesof elementsrepresenting other species. With respectto compositionalsimilarity, it Orvig (1951)noted that someofthe conodont has been noted repeatedly that phosphate elementsin his collectionfrom the Silurian of mineralizationis widespreadwithin the animal Estoniaand the middle Devonian rhich are the ofOhio have kingdom and henceis not, ofitsell evidenceof "a baseconsisting ofa substancewhich differs donts collected anything more than an enzymatic system that . . . frorn. . . materialof the rtilaginous pal- tooth-likecusps. . . hasnot beencompletely modified to permit ac- but in this substanceone is not a are required concernedwith cumulationofcarbonate minerals. Note, in this any kind of bone tissue."He pointed . in Myxine. I also out regard,the recent determination by Tillier and that the Middle OrdovicianHarding brtable just to Sandstone Cuif(1986) that the buccalelements of certain of Colorado, which yields elements eiltrer. That is, of Coleodus aplacophoranand scaphopodanmollusks are and a greatvariety ofother types tEerve rmpres- ofconodonts, phosphatic. also yieldsspecimens assigned I havebeen in- to the ostmcod- With respectto shape,I needonly point out erms Astraspis and. Eriptychius nld have been that exhibit that teeth,grasping spines, copulatory hooklets, practicallyall the typesofhard American Silu- tissueknown in and the like, have similar shapesin whatever vertebrates.To my mind, this :served of the statementis sig- animal body they are formed becausethose are nificant becauseit suggeststhat conodontele- Ens preserves the shapes job, that do the not becauseall or- ments with superficiallybonelike materials a1 n might be in- ganisms with teeth,grasping spines, and copu- the baseand specimenscomposed of real bone latory hooklets are closely related. In addition occur in collectionsfrom al;' three likely the samebeds and to those formed in various ways by diferent that tbey may be readily distinguished natus designed by one groupsofchordates, structurcs that are similar with a trained eye. imately ingest to chordate teeth in form and function are Finally, anyone familiar with herd grasping the elegant il- found in distantly relatedgroups such as mol- lustration of Myxine glutinosa in Miiller's F,ir€(d lalam- lusks, arthropods,trematodes, nemertineans, (1836) famous monograph .I join Dawson on the hagfishes gnathostomulids,and chaetognaths.It is thus (Fig. 8.2)is boundto be struck trses of any of by the many fea- no surpnsethat someone,sometime, has con- tures that seemto be shared cuetoped inde- with the best Dre- sideredone or anotherofthose groups as either servedof lhe ScottishCarboniferous soecimens E_<91 'L Dlol.l' -ur prErl sllll 1"q^{ puE 'paJ?druoc uaeq ,tFour 'qlee1 lpouoJ Jo uo4 -(uoc e ?q qslq r qlu{\ sdnoJE olepJoqc Jo 'seurolo^ur'proqcolou Jo ?J"Jl .{ue qc?[ D EsuqqreJ alp 0q1Jo senl"eJ^erll lBrluosse {rq sluauele plel3{s ter{l qanogl uo^e '(986I) rahu"I I 'uosfueg IrssoJ 16l S Jreql 'sseuenbun Jreql azs?qdue u"ql eJorrr pu" pun'I ,q pequcsop f,IluecoJ PtSoloruoal ^eJdu?l #-I' affir 'tnqz elll{ auop seq esle Suqleuos sluopouoc olelu IIssoJaql ur u^roqssernl?eJ lueuruoJd lsoru Fpouo{ rlsou ol Eurfu Jo .funluac e ueqt aJorll Jouq uI aql oJeseqcnod U€ eql Jo slueursle'Jo s^\oH rN 1286r) d "I (EJaocoqcu^qU oql 'Ielluelod uo4e^JosoJd1(ol,fue^ 3 o^eq seJnl"eJ "S Dfi I '^olsreg ue^e Jo '?Trtrld uEpodorgue oqlJo euo '?lelulep qcns ? 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formation we have on soft-part anatomy Branson,E. B., and Mehl, M. G. (1933).Con- speaksto us in severaltongues. Thus, I am odont StudiesNo. l. Univ. Missouri Studiest, .rc be€n trying comfortablein consideringthe Conodontaan 5-72. Briggs,D. E. G., Clarkson,E. N. h Chordata extinctphylum of small.solitary marine K., and Aldridge, or ani- R. J. (1983). The conodont aqimaL Lethaia crtebratephyla, mals,with compressedor depressedvermifom 16,t-14. rsrated convic- bodies that were soft except for a variously dif- Ctark, D. L., Sweet, W. C., Bergstriim, S. M., 'organizational ferentiated assemblageof phosphatizedepithe- Klapper, G., Austin, R. L., Rhodes, F. H. T., a aroselate in lial elementsin the cephaliclobe. The elements Mtiller, K. J., Zieg)er, W., Lindstriim, M., E Miller, J. F., and Harris, A. (1981). c Paleozoic by which conodonts represented G. Con- and are in the fos- odonta. Pt. W, Suppl. 2 il Trcatiseon Inverte- since sil record may have functioned as grasping brate Paleontology(ed. R. A. Robison), Geol. -tracted)Han. However, spinesand buccal or pharyngealteeth. And the Soc.America and Univ. Kansas,202 pp. lin the late Pre- cosmopolitanand broadly facies-independentConway-Morris, S. (1976). A new Cambrian lo- phophorate ly of metazoan distributionofmany speciessuggests they were from the BurgessShale of British Columbia. Palaeontology 19, 199-222. le such pelagicanimals, probably organi- nektonic, although Dawson, J. A. (1963).The oral cavity, the'jaws' hve survived, others,of more limited distribution and facies and the horny teeth of Myxine glutinosa. Pp. hce" between dependence,may have been nektobenthicor 231-255 il The Biology of Myxlze (ed. A. Bro- ruch less than even benthic. Conodonts were probably a dal and R. Fange).Universitetsforlaget, Oslo. (1943). rvrvors. minor phylum.never parlicularly conspicuous Dubois, E. P. Evidence on th€ nature of conodonts. Pal. 17. 155-159. rtte idea(albeit componentsof Paleozoic Triassic "L or marine Ellison, S. P., Jr. (1944).The composition ofcon- t-aflhropod" is faunas.Their ultimate extinctionat the end of odonts.J. Pal. lE, 133-140. I independently the Triassicwas probably the cumulativeresult Gross, W. (1954).Zur Conodonten-Frage.,Serrck- te gradesof or- of a long decline through the Carboniferous enbergianaLethaea 35, 73-85. d rhat at least and Permianand a gradualreduction in geno- Harley, J. (1861).On the Ludlow bone-bedand its crustaceanremains. Q. L Geol,Soc. London 11, confiisingcom- mic diversity. In spite of their probablerarity 542-5s2. thn characters, in Paleozoicand Triassic seas,conodonts are Hass, W. H., and Lindberg, M. L. (1946).Orien- fled to survive abundantand commonas fossils right up to the tation of crystal units ofconodonts. J. Pal.20, lested recently top ofthe Triassic,probably because they were 501-504. Hinde, (1879). ne members of blessedwith heala, chemicallyresistant skele- G. J. On conodonts from the Chazy and Cincinnati group of the Cambro-Si- lave been as- tal elementsthat providedthem a placein pos- lurian, and from the Hamilton and Genesee- lbn to several terity denied to other less suitably endowed shaledivisions ofthe Deyonian in Canadaand :nlatlves, may groups. the United States. 0. "/. Geol. Soc. London 35, organizational 351-369. Hubrecht, (1883). rtitrgdom!)that A. A. W. On the ancestralform References of the chordate. Q. J. Microsc. Soc. 23, 349- mmotiids and 368. rps. And it has Aldridge,R. J., Briggs,D. E. c., Clarkson,E. N. - (1887). The relation of the Nemertea to tt eventhe l/en- K. and Smith, M. P. (1986).The amnitiesof the Vertebrata.Q. J. Microsc. Sci.21,605-644. conodonts-new D mor€ than a evidencefrom the Carbonif- Hyman, L. H. (1951). The Invertebrqtes:Plqty- erousof Edinburgh,ScotLand. Lethaia 19, | -l 4. hates and helminthes and Rhynchocoela-The acoelo- ver- Aldridge,R. J., Srnith,M. P., Norby,R. D., and mate Bilateria.y.lL Mc Graw-Hill. New York. htives may re- Briggs,D. E. G. (1987).The architectureand 550pp. I of the "chor- functionof Carboniferouspolygnathacean con- - (1959). The Invertebrates: Smaller Coelo- tral sides into odontapparatuses. Pp. 63-75in Palaeobiology mate Groups. V. 5. Mc Graw-Hill, Ne\ry York, of Conodonts(ed. R. J. Aldridge). Ellis Hor- 783pp. €-, the Echino- wood,Chichester, 180 pp. James,U. P. (1884). r phyla, or even On conodontsand fossil an- Barskov,I. S.,Moskalenko, T. A., andStarostina, nelidjaws. Cincinnati Soc.NaL Hist. J.7. 143- L. P. (1982).NorTe dokazatel'stvaprinadlezh- 149. r-Yof trying to nosti konodontoforid k pozvonochnym.Pal Jefferies,R. P. S. (1986). The Ancestryofthe Ver- : bas done little Zhur. 19E2,80-86. [English translation in Pa- tebrates. Carnbidge Univ. Press, Cambridge, ipeness. Their leontologicallournal 1982,82-90.1 376 pp. Bengtson,S. (1976).The structureof someMid- Kirk, S. R. (1929). ftatures of the Conodontsassociated with rhe dle Carnbrianconodonts, and the earlyevolu- Ordovician fish fauna of Colorado-A prelim- le1- have com- tion of conodont structure and function. Ie- rnary roe. Am. J. Sci.Ser. 5, 18(108),493-496. r linle hard in- thaia7, 185-206. Klapper, G., and Bergstriim, S. M. (1984). The b4 .DJ ErO nt{

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*:l afrnities t9-452. APPENDIX A. A SUMMARY CLASSIFICATIONOF THE rclationships u- CONODONTA I An €cologic 69-880. EEZ Oan ex- Els with Pro- Phylum ConodontaPander, 1856 2Pseudooneotodus Drygant, 1974 rHridge, R. J. ClassCar.idonti, new ScabbardeI Ia Orchard, I 980 6e lower Si- Order Proconodontida. new Semiaconti odus Miller, I 969 le apparatus Family Proconodontidae Lindstr6m, Stauferella Sweet,Thompson, and rcdonts. Pp. &n* (ed. R. t970 Satterfield,1975 rst€r, 180pp. E oc o n o d o nt us Miller, 19 80 2Strachanognat hus Rhodes,1955 l rhe Harding ProconodontusMiller, 1969 Teridontus Miller, 1980 lcolorado. "/. Family Cordylodontidae Lindstriim, TropodusKennedy, 1980 r970 UtahconusMiller. 1980 It grasping m protocon- CambrooistodusMiller, I 980 VaiabiloconusLanding, Bames, and CordylodusPzndet 1856 Stevens.1986 ,'aaimal+on- I apetognathus Ianding, | 982 FamilyClavohamulidae Lindstrdm, qtrore? C -R. Family FryxellodontidaeMiller, l98l t970 tz Fryxel lodontus Miller, I 969 Clav ohamulus Fumish, | 938 16). A classi- EdoDts, with Family PygodontidaeBergstriim, 198 I H i rs ut o d o nt us Mjlle\ | 969 m and Mis- N eri co dus Li'j.ds1'Jom,| 95 5 Seftat ognathus I-fJe,| 970 E0c. 58, Art. PolonodusDzik, 1976 ?Paraserratognat hzs Yang, 1986 PygodusI-amont and Lindstriim, Family AcanthodontidaeLindstrtim, md possible 1957 t970 aeL 19, 321- Order Belodellida, new Acanthodus Fu;mish, | 938 f€arly Cam- Family Belodellidae Khodaleyich and Co r nuodus F ahrircrs, | 96 6 tondon l3l, Tschernich,1973 D repanodusP ander, 1856 B eI o d e I Ia Ethi'lgtoll, 19 59 Parapal todus Stov$e, 1984 ) Uber Con- Coeloc erodo ntus Ethington, 1959 ScalpellodusDzik, 1976 Sizungsber. Dvorakia Klapper and Barrick, 1983 Ulric hodina Furnish, | 938 Stoladus Lindstrdrn, 1955 Family Drepanoistodontidae Fihraeus Il aI I i se r odus Serpagh,| 967 and Nowlan, 1978 Family Ansellidae Fihraeus and D repanoistodus Lindstrdm, I 97 I Hunter, 1985 Paltodus Pande\ 1856 AnsellaFirhtaeu;s and Hunter, 1985 Paroistodus Lindstrttm, I 97 I 2Hamarodus Yiira, 1975 Order Panderodontida, new Family Dapsilodontidae,n€w Family PanderodontidaeLindslriim, B esselodus AJdridge,1982 r9'10 Dapsi lodus Cooper, | 9-l6 B eI o di na EthilJigton,| 9 59 ClassConodonti Branson, 1938 CulumbodinaMoskalenko, 1973 Order Protopanderodontida,new N eo p and er o dus Ziegler and Family Protopanderodontidae Lindstrtim, 1971 Lindsrrtim, 1970 PanderodusEthinglon, 1959 Gly pt oc o nus KenJc,dy, 19 80 Parabelodina Sweet, | 9'l 9 M onocostodus M.rller, 1980 Parapanderodus Stouge, I 984 Oneot odus Lindstriim, I 955 Plegagnathus Ethington and Fumish, ParutahconusLanding, 1982 1959 Pr otopanderodus Llndstriim, I 97 I Ps eudobe lodina Sweet, 1979 '4r"I pu? PO rJpro Z86I I DlltI 6t6I 's?uroql snrywuSstlapd ^qdrnw lqx,r' vE6l z96| 'relllt.l^l snpou)uan J puE JI 'IqoI I uosu?rgsnqpuSolDdy 8t6I \qaw pu? uosuergsnpourl 926J'relss?g e?prugporuoud,{yrueg g/61,^otaudr-I snqpu8otuv F"V .{rzq .JEIINW rs gL6l uoporttoltg I.56I puE F-u,ad €€61lqot{ uosuergsnpowst.tg puErollnN e?pnuopouclAIIlu"C fr-,a-g EE6I 6961 pu? uosu?rg ll '1tIoII snqpuSoqn)i 'lpu?c pu? slJEc, utpoJDpunpv Ea_i E€6I Lr6l qrr/f 'lqew pup uosu"rg snqpu&o.tlq) 'uosueJgpue uosuergsnpoluolsl(J tl,Drtl tt6l 'tqetl zL6l pue

VJNOCONOJ AHI 98r A SUMMARY CLASSIFICATION OF THE CONODONTA t87 llae Bergstrilm, Hibbardella Bassler,1925 Family SpathognathodontidaeHass, I dioprioniodusGlnnell, 1933 l9s9 r6m, 1983 Kl adognathus Rexroad, I 958 Amydrotaxis Klapper and Murphy, r. 1966 Oulodus Brarson and Mehl, 1933 1980 ftr. 1935 Prio ni odina Bassler, 1925 AncyrodellaUlich and Bassler,1926 he Harris, PristognathusStone and Furnish, A ncyrodeI loides Bishoff and 1959 Sannemann,1958 mson and ?Ligo nodina Bassler, 1925 AphelognathusBranson, Mehl, and ?Lonc hodina Bassler, 1925 Branson,l95l L 1938 Family BaclrognalhidaeLindstriim, B ispat hodus M.ilrlle4 | 962 rb and Harris, t9'70 E ognathodus Phllip, | 965 BactrognathusBranson and Mehl, Lochriea Scott, 1942 ton and Clark, 194l Mehlina Y oungquist, 1945 DoliognathusBranson and Mehl, OzarkodinaBranson and Mehl, 1933 ad Harris, t94l Pandori nel I i na M;jller and Miiller, Dollymae Hass, 1959 t95'l Eotaphrus Pierce and Langenheim, ?"Plectodina" (new genusfor specres -,genusfor t97 4 without pastinateP elements) Ete P E mbays gnat hus Metcalfe,I 98I PolygnathoidesBranson and Mehl, ScaliognalhusBranson and Mehl, t933 t5 t94l Pseudopolygnat hus Branson and B5 Staurognathus Branson and Mehl, Mehl, 1934 33 194l Rhachistognathus Dunn, I 966 r llass, 1959 Family EllisoniidaeClark, 1972 ScaphignathusHelms, 1959 t935 EllisoniaMij.ller,1956 Torlodus Weddige, 1977 rd Mehl, Furnishius Clark, 1959 VogelgnathusNorby and Rexroad, Gladigondo I elIa Miiller, I 962 1985 : Lindstriim, Hadrodontina Staesche,I 964 Yaoxianognat hus An, | 985 Metillina Kozur and Mock, 1974 Family KockelellidaeKlapper, l98l a|IOmand Pac hycladina Staesche,I 964 A ncoradelI a W zlliser, 1964 SweelinaWardlaw and Collinson, KockeI ella W alliser, 195'1 rrp.elj, 1974 1986 Family PterospathodontidaeCooper, E- Mehl, and Family GondolellidaeLindstrdm, 1977 l9'10 ApsidognalhusW alliser,1964 dstrdm, 1970 CarinellaBt trov,1973 Astropentagnathus Mostler, 1967 rtu. l97l CypridodeIla Moshey 1968 Aulacognathus Mostler, 1967 I Epigondo I ella Mosher I 968 Carniodw Wallisel 1964 Gondolella Statffer and Plummer, Johno gnat hus Mashkova,I 977 Etrson and 1932 Pter ospat hodus W alliser, I 964 Misikella Kozur and Mock, 1974 Family PolygnathidaeBassler, 1925 nd Mehl, Mosherella Kozur, 1972 Ancyrognalhus Bransonand Mehl, NeogondolellaBender and Stoppel, 1934 ud Mehl, r965 ?A ncyroI epis Ziegle4 1959 Neospat hodus Mosher, I 968 Polygnathus Hindq | 879 I Mehl, 1933 Platyvillosus Clark, Sincavage,and Polylophodonta Branson and Mehl, Stone1964 t934 sler. 1925 Pseudolurnishiusvan den Boogaard, Family Palmatolepidae,new Dd Mehl, 1966 Klapperina l-ane, Miiller, and Xaniognathus Sweet,1970 Ziegler,1979 tL 1982 Order Ozarkodinida Dzik, 1976 MesotaxisKlaEEer and Philip, 1972 FruJE ,{UEJOJ E iaqt'osJnoc r uI sueqJ oql q aql Jo lsour qr Jo sJor{l'nD 'pz?A-ruIlttr"u l' uotlEuuoJul €€6I 916I 'lqol/{ pu? uosu?rg snuozoalalsl pu" 'nzoa snq|ouSouotl fftts e^Eq I xrp 'reFsolI hm uI 'su?eu] tt6l 9g6l' ralill sn[DuSouDttouroH rt€s pJspusls 'lqel l pu" uosuerg snpoap)oaN I L6l r Jqt ruo{ sal3 9S6l 'lsel;l.SsnuoronWi. 'llural I pu" rnzo) snpoqpuSoldte lql uo uollu (u €g6l 'lr{el\I pue uosuer[ s7tpozloJ 986I'roue{ oeplqlButolee,4rs,(Iru?C puSoaor.lJtv ts-rl\run ol?ls 8€6I 'uosrflnJ snq vt6I pueuosuerli snpouDtuqqns r43DI lrel,il tt6l 1qen lqa4 L pue uosu"rg eBPrluopooloJ v96l r pePnpur selc u.rrou)lun^lltu?d leplo 'qsrunc pu? psoJxedsnpoapulH ! h$ulueseJded 9L6l €16['uu"Iueseegs?mpqpv '^oe$lolv pu? snqlDuBrDtD'J u6r foloqtuour Jo ^olsuv q i[suoqdaJYo LS6l goqcsrgsnrytDuSotsary 5lrelJ e?prluopoql"u8rqcuv 'sopoqd 'roururnld^IIueC I pue 'IJor\ I86I z€6I q augepsaJueJ pue uDsnv oeplqleuEolsaw .[IIIuec pu? ra.Un?lssr,rporypuSotda4s \ sfrJJds pepnlc w6l OL6l 'uunq snpoqpuSoaN pB rqncryed 'lqatrAlpue uosuag snqpuSotr.ldDJ t[6I 'qloarstulloH pue sure[ sapoxpDuSorp t qr ur apnlcul 6961'ernlq J pue uusnv snqpuSotlod 'lleuun9 srporllDuSotpl I5 ilrseu aqt Jo 'sepo\[ I€6t Erq-luopouoc 696I'atnjc 9961'r]!nq snpoqpuSouq)ao a* araql qclqlt{ pu" unsnv'sapoqg m 4uu Eo pt1 2 €€6I 'qiloastullloH pu? suJ"H eepuuopoqt?u8orpl /(Fu?d lro reddn pu? sL6r qJPluopouoc 'fieqcuw pue u4snv snqpuSnqSotJ 696 l' r.Ieerz s-npotl tD uB o I o t d gsgt snpoqpu) *?-dE Ertsorq? €g6l 'qUo^\sAuIIoH 'rePldP-d ir rlqdel8rt?4s pue srrJeE flqpu8sn^D) ,neu'esprl.uopoqlBuo .IIAqCIII^I ^IIIu"C + uo su?q3 uI 9/6I vn6l pue urtsr Snqpu8 ouI oJrtdoC 'Iqol l pu" uosuBrgDllapouotldts L96l 'euy\ snqrDuSoppv r86l 186l 'sapoqu 'Sreqpuespue reltelz sflqtouSouDqv pue ur$nv e?pllleutsn^?J 186l'sopoqu ^lruEd pue uqsnv eeplql"uSopllA,(lrureC ,xICNUddv ZL6 l' ryzlJ snqpu8otaats gL 6 l, mzo>ls lltDu 3 ! a qD V 996 I' relaerzsnq p u3 o tp t w| rS Z L6l'. )4J€lJsnpoqtDu8 ofi at FoaN 9Z6r I L6l 'Jrrzo.)onaJD.tDSI 'relss?gpu" rIJuln sldappulDd

VINOCONOJ :IHl, 88r ; 19'72 APPENDIX B. STRATIGRAPHICRANGE CHARTS in and rnd In charts on the next 14 pagesI indicate the References slraligraphicranges of 562conodont species in Higgins, A. C., and Austin, R. L., editors (19E5). a biostratigaphicframework that includes156 A Strutigraphkal Index of Conodonts. Ellis I Mirchell, conodont-definedbiozones and, in the Lower Horwood, Chicheste\ 263 W. and Upper Carboniferous, severalintervals for Klapper, G., and Johnson, J. G. (1980). Ende- tin and which there are currently no widely accepted mism and dispenal of Devonian conodonts."[ conodont-biozonalschemes. In choosingwhich PaL 54(2), 400-455. Klapper, G., arld Ziede\ W. (1979). Devonian lin and of the nearly 5000named conodont species to conodont biostratig.raphy. Spec. Papers in Po- include in the following charts,I followed no Iqeont. 23, 199-224. d Mehl, particular guidelines. By and large I have in- Kovacs, S., and Kozur, H. (1980). Stmtiga- cluded specieswhose first and/or last occur- phische Reichweite der wichtigsten Conodon- (ohne rencesdefine boundariesin the biozonal frame- ten Zahnreihenconodonten)der Mittel- h and und Obertrias. Geol. Paliiont. Milt. Innsbruck work, and I haye omitted species with r0(2),4't-'18. exceptionallylong rangesand/or poorly known I-ane, H. R., Sandberg,C. A., and Ziegler, W. Alekseev, or morphologically nondescript apparatuses. (1980). Taxonomy and phylogeny of some Representativespecimens of many of the spe- Lower Carboniferous conodonts and prelimi- cies included are illustrated in Chapter 5. nary standard post-Siphonodella zonation. Geol. et Palaeont.14, ll'l-168. I and I-ane,H. R., and Struka,J. J., (1974).I-ate Missis- Mark Kleffner, a doctoral student at The Ohio sippian and early Pennsylvanian conodonts, 938 State University, generously abstracted infor- Arkansas and Oklahoma. Geol. Soc.America pp- t 1933 mation on the rangesof important Silurianspe- Spec. Paper 152, 144 from much more inclusivecomposite Ritter, S. M. (1986). Taxonomic revision and cies the phylogeny post-Early graphic of Permian crisis bisseli- f,ehl, slandard section he has assembledby whitei Zone conodontswith commentson Late means.In compilingother charts in this appen- Paleozoicdiversity. Geol et Palaeont. 20, 139 - Xehl, dix I have supplementedmy own records with 165. information from sourceslisted below. Thus Wardlaw, B. R., and Collinson, J. W. (1986).Pa- authors of those rcports must be credited for leontology and deposition of the Phosphoria Formation. Contr. Geol. Univ. Wyoming 24(2), went into most of the hard work that building to7 -142. the charts in which their data are used. Of course,they must alsoshare some ofthe blame for any errors!

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Chrfi 9. Ranges of selected Triassic conodont species. Index

Absarokasequ€nce, 132, Apparatuses,38 Acanthodontidae,54, lE5 €laborationof, 142 Acanthodus,54, l85, FiE. 5.7 reductionof, 143 Acodus,6l Apsidognathus,99, 187,Fig. 5.43 "Acodtu," 60 Archaeocyathida,173, I82 Acontiodus,53 Archeognathus,123, l8l, 188,Fig. 5.59 Adcarinal trough, 100 Aschelminthes,| 73 Adenticulate process, I 6 AshlockFormation, 155 Adetognathus,120, l2l, 122, 136, 137, 160, 16l, 163, Aslraspis,l8l 188,Fig. 5.s7 Astropentaghathus,99, 187,Fig. 5.43 Aethotaxis,ll5,ll7,137,161, 164,I87, Fig.5.54 Altachmentsurfac.e, 40 Agnatha, 177 Aulacognathus,99, 187 Alate g€niculateconiform el€ment,16 Au lobodui, 186 Alat€ nongeniculateconiform element, 16 Alale ramiform element,17 Bactrognathidae,83, 145,156, 187 Albid (crowns),13, 14,52 Bactrognathus,83, 84, 136,159, lE1, Fig. 5,32 Alternognathus,89,96, IO1, loE, 188,Fig. 5.49 anchorarius,84 pseudoslrigosus,107, 108,Fig. 5.49 excavatut,84 Ambalodusgalerus,99 hamatus,84 Ammocoetelawa, 177 Balognathidae,63, 64,1l,15, 144,186 Amoryhognathus,63, 64,7l, 134, 156, 165, 186,Fig. Balognalhus,63 2.11,5.15 Baltoniodus,63,64, 65, 186, Fig. 5.15 ordovicicus, 26 BaltoscandicEovince, 167 Afi p hioxus. S ee B ruhchtostoma Bars,15, 16 Amydrctaxis, 89, 93, 95, 99, 135, 187,Figs. 5.39,5.40 Basalcavily, 13, 15, 40 Anchiglathodontacea, I I 7 Basalfilling, 12 Anchignarhodontidae,90, 92, 1t 5, I17, 188 Basalpit, 13,22 Ahchignathodus,l17 Basalplate, 179 typicalis, ll7 Base,13, 15 Ancoradella,89,93, 98, 187 Belodella,45, 49, 185, Fig. 5.3 ploeckehsis, 98 B€lodellida,42, 45, 49, 133,185 Ancyrodella,89, 96, 106, 135, l4l, 187,Figs. 5.39,5.41 Belodellidae,42, 49, 185 Ancyrodelloides,89, 93, 95, 96, 98, 99, 106, 135, l4l, Belodia,18,55,57, 58, 141, 185, Fig.5.10 187,Fiss. 5.39, 5.40 calciprcminens,57 Ancyrognalhus,lO2, 187,FiE, 5.46 comprcsso,58 Ahcyrclepis,187 monilorcnsis,58 Angulatepectiniform element,2l Berys!rcemoghathus,75,76, 186, Fig.5.26 Annelids,l7l, t72 extensus,l6 Ansella,49,50,167, 185, Fig 5.3 Besselodus,50,51, 185,Fig. 5.3 Ansellidae,42, 49, 185 Bimembrateskeletal appalatus, 24 Anterior process,16 Bip€nnateiamiform element, 18, 24 Antler flysch trough, 157 Bnksleldia, 65 Antognathus,69, 10, 186 Bisegminiscaphat€pectiniform element, 22 Apatognathus,81, I16, 186,Fig. 5.30 Bispathodui,89, 90,94,96,97, 136, l4l, 159,187, Aphelognathus,73,91,93, 134, 154, 155, 156, 187,Fig. Figs.5.39,5.41 5.37 aculealus,96 "Aphelognathus,"9l, |86 biswthodus,96 gigas,9l spinulicostats,96 kimmsv/ickensis, 9l stabilis,96,97,109, I12, Fie. 5.50 Aplacophora, 172, 173 utahensis,96, 159 Appalachignathus,1 5, 16, 186,Fie. 5.26 Blades,15, 20

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Distacodidae,36 Fibrous struclure, 14 Distacodontacea,41, 42, 5l Flotant marsh, 164 Distacodontidae,36, 5l Form taxonomy, 5, 35 Distacodus,51,54 Freeblade, I13, ll7 Distomodontidae,67, 68,11, 134, l4l, 144, 167, 186 Fryxellodontidae,48, 185 Distomo&rs,66, 61, 68,1 l, 98, 186,Fie. 5.19 Fryxellodontus, 48, 185, Fig. 5.2 kentuckyensis,61, 68 Fumishinacea,42 Diversity cycles,130 Furnishiut,85,86, 138,187, Fig. 5.33 firsr-order, 130,132, 133 Fus€dcluster, 24, 3?, 41, l7l long-term, 130, 132, 133 second-order,13 l, 133,l 40, 146 GamachighalhrLt,64, 65, 67, 186,Fig. 5.15 Dolabrateconiform elemcnt, l8 Geniculateconiform element,15, 16, 25 Dolabrateramiform elemenl, 18, 24 Germanic Province, 168 Doliognathus,83, 84, 136, 159, 187,Fig. 5.32 Gladigondolella,87, 138, l8?, Fig. 5.34 Do ytnae, 83, 136, 187 meeki, 81 Drakes Formation, 154 tJtY?toconus,)J, l6)! frg. ).) Drcpanodus,54, 185,Fig. 5.? quadruplicatus,53 slrkttus,56 Gnathodontidae,89, 95,96, lO9, ll2,I13, 135,l8E Drepanoistodontidae,54, 185 Gnathodus,109, Ill,ll2, 136,14l, 159,t88, Fig.5.50 Drepanoistodus,54, 55, 59, 134, | 57, 185,Fig. 5.8 austi L lll sp. aff. suberectus,23 bilineatus,IIO, I I t, 112,Fig. 5.50 Dvorakia, 45, 149, 185,Fig. 5.3 anneifurmis,109, Fig. 5.50 delicarus,109, t1l, Fig.5.50 Echinodermata,173, 182 girtyi, l l l,137, Fig. 5.50 EinfacheZahne, 15, 35 praebilineatu,s,lll Element, I I p nctalus, lO9,I10, Fig. 5.50 Elictognathidae,89, 96, 106, 136, 188 semiglaber,111, Fig. 5.50 E lictoghathus, 106, 107 texaws,lll,Fit 5,50 Elltsonia,83,85, 86, 89, 137,138, 139, 161, 163, 187, typicus, 109, I10, Fig. 5.50 ]7-Fi& 5.35 Fig.5.33 Gnathostomulids,173 teichefti, Il7 Gondolella,81,88, 89, 137, 138, 142,16I, 162, 163, ttiassica,86,87 165,166, 187, Fig. 5.35 Ellisoniidae,83, 85, 142,166, 187 navicula,1'l Embaysgnathus,84, 18?,Fig. 5.32 Gondolellacea,41, 42, 78 Enanliognathus,18, 83 Gondolellidae,78, 83, 87, 88, 89, 138,142,146, 166, Eobelodina,5T 187 Eoconodontus,46, 47, 185,Fig. 5.2 Gondwanaglaciation, 134 Eognathodus,89, 93, 94,95, 96,91, 135, l4l,181, Grant Irke Formation, 155 Fies.2.11,5.39,5.41 Grier Member (of Lexington Limestone),155 sulcalus,26,96 Eoneop oniod s,72 Habit (ofconodon$), 148, 150 EopI acog nat hus, 1 l, 72, 102, | 43, 186,Fie. 5.21 benthic,152 Eotaphrus,83, 136, 159, 187 nektobenthic,l5O, 152,164 Epigondolella,87, l3'1,142,146, 187,Fig. 5.35 pelagic,150, 152, 164 ,g/rkd, 81, 186,Fig. 5.30 Hadrcdoatina,85,86, 138,187, Fig.5.33 divaricala, 8l Hadrcgnalhus,68, l4l Eriplychius, l8l sta rcgnathoides,68 Eismod s, 18,79,81,134, 186, Frg- 5.29 Hagfrsh. See Myxine quadridactylus, 79 Hamarcdus,49,50,185, Fig. 5.3 Erratrcodon,78, 79, 81, 85, 186,Fig.5.29 Harding Sandstone,l?7 palu, 79 Hemichordata, 173 Euconodontelement, 42 Heterochrony,145 Euconodonts,4l H ibbardella, 11, 8 | , 82, 84, 187, Frg. 5.29 Evolutionary index. ,SeeIndex ofevolutron angulata,8l Exoc hognot hus exwnsu-s, 68 Hibbardellacea,42, 7E Il. 137,139, Extensiformdigyrate element, 18, 24 Hindeodus,l15,l16, l17, l18, 120,137, 139, I40, 159, 160,16l, 164,188 Fairview Formation, 155 uassidenlatus,I 15, 116,Fig. 5.54 Falcodus, lO4, 106, loj crlstulus, | 16, I l'1, Fig. 5.54 anguhts,lO7 jufensis, I 17 Fibrous elements,?9, 81, 165 minulus, lI7 ZSg 3H '88t 't9t 'Ltt 'bt t 'tlt 'snpoqlouSoaN n9I'7Sl'09l lapour uo[eaofeslerele'l ai = a:,4:autloJ 6S S 3r{ '881 'EZt 'snpoaproaN gl 'sseDordlerele'I !L =r.:: !?lBlEd z8l 9/I Sr.uro^\ueouruoru0N z8 'sntllDuSopquDT ES:,r:-:: jiOpaEd IE'Sa aWaUOl)aN _=) -- :I|lJDd sgl'euneJ oqs&oN 9Sl 'uorlEturol odo) F:: :::isod- ed tLl Lql 'ttl 'L6'96 '€6 'oEplllelolro) _itnrsod F= ,: d '0SI 'ttl 'tt '0t '8t 'l,t 'tZ 'S '(s)eSElquesseIErnleN 86 'sIJlqDuD^ L6',slutloJllnuo) I 9/l 'saploulx,{w z| s'eIJ' L9t'ItT'86't 6'96'f 6'68'ollalal)ox -! ,//l ,Boprourx,{I 6al l LV S tuf 'tjl 'squodslP _a::--uol 081 '6ll Jo snlerBddeIenBuII bol 'DtDrDdslp ,08I ,61.t,9Ll ,osou|try8 I8I Ln S Ald'n}t 'Da^P)DdstP !: :': :: flrJ z8t 't8I '08I '6Lr'LLr'9Ll'SLl'lt'au! 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'atJ 't '0 '69 ' 'nplwIrsoi qtI'OZl 'Lll's!|nldtt l! -: i oz'9 L L L9 st9 oL 69',SuaXsar)tlalDl ts s 3!l '9t I ',stt 'sqaDs '_i .2loPuoSoaN 0z s 3u'98t ',|L'oL',69',Lg',snpouxaIJT (Panu1lu ox)'snqoaqu1H INDEX

Neogondolella,87, 88, 137,138, 142, 146, 187, Fig. Palmatolepis,102, 104, 105, 135, 136, 145, 188,Figs. 5.44,5.4',7 bisselli, 131, 138 pe obata,105 clorki, 137 rugosa, 105 mofiberye sis,138 rugosa ampla, 105 pfaeD6te t, tt I rugosa lrachyleru, 105 Neomuhioistodus,2L,72,73, 186,FiE 5.22 Itia gula s, lO5 Il, l0r clypeus,73 PaLodus,53,54, 185,Fig. 5.8 ! Fs 5.51 Neopanderodus,55, 57, 185 Pander,Christian Heinrich, 3 Neoptioniodus,82,83 PanderSociety, 7 Neospathodus,87, 137,138, 142, lE7, Fig. 5.35 Panderodontacea,4l ! 154,155 Neostteptognathodus,ll7, ll9, 131,138, 188,Fig. 5.55 Panderodonlida,42, 45, 55,56, l4l, 185 Neoteny, 146 Panderodontidae,56, 167, 185 Ne codl,ts,48,185 Panderodus,55, 57, 58,59, l4l, 156,167, 170, 185, Neurodontiformes,14, 36, 79, 81, 155 Fig.5.9 Noixodonlus,64, 186 berystrcerni,56,58, 141 Nongeniculateconiform elemenl, 15, 16 gr4cuts,zJ, rtE z.t Nonh American Midcontinent Province, 167 sulcatus,5l Nonh Atlanric Provinc€, 167 unicostatus,32, 57, Frg. 3.3 Nolhognathella, 104 Pahdetulepis, lO5 Pandotinellina, 92,93, 95, 96, 107, 123, 136, 142, | 59, Octimembrateapparatus, 64 l8?, Fis. 5.37 Odontog tiphus, 28, l'l 3 insita,93,96,l2l, 123 omolius,173 Parubelodiha,18,55, 58, l4l, 185,Fig.5.l0 j Oelandodus,61,185, Fig. 5.13 denticulata,56, l4I Oepikodut,63, 186,Fig. 5.14 Paruchtognathus, 79 Otrshorefauna, 165 Paraconodonta,4l I Fre.5.58 Ohio Valley Province, 167 Paraconodontida,41, 42, 45, 175 Oistodontidae,42, 50, l4l, 186 Paraconodonts,28, 41, 42 Oistodontinae,61, 186 Paragnalhodus,lll Oistodus,61, 186,Fig. 5-l3 Parupaltodus,54, 185 Oneotodontidae,52 Parupandetudus,55, 56, 185,Fig. 5.9 OneotodtLt,52, 53, 185,Fig.5.5 asymmetficus, 56, 51 Origination-extinctionratio. SeeIndex of evolution striatus,56 Ostracoderms,176 Parapet,109 Oulodw 18,81,154,155, 156, l81,Fie. 5.29 Paruprioniodus,73, 134, 186,Fie. 5.22 se atus,8l costalus,73, l4l Outsideshale, 161, 163 Paraserrutog nat hus, 185 Ozarkodina,91, 92,93, 95, 96, 98,99, l2O, 115, 142, Psroistodus,54,55, 185,Fig. 5.8 187,Figs. 5.38,5.39 horridus, 55 abrupta,97 Porutahconus, 53, 185 confluens,33 Pastinatep€ctiniform element,2l inclinata,92,94 Pastiniscaphate pectiniform element, 22 murchisoni, 177 Patrcgnathus,96,120,122, 136,I88, Fig. 5.57 n. sp. of Bergstritm,9l Pb position (or element),24, 30 renscheideksis, 95 Pectinat€t€eth, 19 sannemana,96 Pectiniform elem€nt, 15, 20, 24, 36 It2'ln@ se$,93,94,95,99 Peda s, 65, 66,67, 68,7L, 134,135,146,l86,Fi& semialtemens,93,106 5.18 tortilis, 37 lalialalus,7I Ozarkodinida,42, 45, 75,89,90,lJ4,135, 140,l4l, Pelelcysgnathus,60, 65, 65,69,70,71, 135, 136, l4l, 187 142, t46, t86,Fie. 5.20 csakyi,lO L 1,14,150, P position (or element),24 inclinatus,70 Pa position (or element),24, 30 index, 70, Il, l4l Pachycladina,85, 86, 138, 187,Fig. 5.33 "Pelekysgnathus," 7o Paedomorphosis,145, 146 Peiodon, 18, 35, 16, 77, 156, 186,FLl- 5.27 Palataltooth, 179 acuteal4, to, t t '17 Palmatodella, lO4 Jlabellum, t 5.52 Palmatolepidae,89, 102,106, 135, 187 gtanats, | | _€ selluros l-: tZ'snl€Jedde lElolols elelqueElnltumo 9OI'SOt'snrn^ els"Souelos , ,stp/qp| Zil 8l 'luauela uuoJluel oleuelupenb LB LE I !Eq5 Etala)ls tZ'snleredde leFIeIs el?Jqueuupeno 66'srltDads L-trdde plelols ool 'tnulloras -Er.,-1/Souoqdls a 9bI'o as 66'96'aqauald 'Dmqfis al'_01 66'ot/tl gEI 'ZOl'dnort snp6oxopou gbl 'sn uasuo ool'sq oaqo slw t ortn8ull 'ErDJ\dnp ,rol ,strollwll 'El':::tJJnsaoia.t Z S 8td'S8I 'E '6n'W'sllPo8td g0l 6r-! 8t s 98I 'Zt 'e€PnuoPo3,{d 66 sqotsotllol a-51 oqpu 8ot!d,towo ool '66 snsra^ul -,PPouoqdls 86'sap1 l+ rTerqtllaujlres 6€S 66'8raquor3 -t-':.DuSoutras E '3U'r8t'f '90t'66'86'96'€6'68'snpoqtDdsoraq L€ '9 '' 's lqnp rF resPrluopoqledsoreld {erqEarutdas ,8I 't€l '66 '86 '96 'S, 'Zt 66'suaJslqap stuttruDolLuas zL'slsoql^arq 9OI 't}l 'Srllolslt tE:Ad 4euIur8eS zz s'3!J',981 'rEI 'EL',ZL',st1polluox'rald lol 'snrDlsot boJd irepuoJos 16,.'sryt7u8tlodoPnasd,, lol'ool'todoor !FXr BOBTSOdpS lt 9 8lJ 't8 t '6St '9Et 'L6 'snqtouS/tlodopnasd 6SI'ltl'9€l'slunwraoJ 'mwrld tA.A't- 99 'snwapuodopnzsd 9n'9'r'.s'6E9 s8U'Z8r'691 ',9nl',Wr',g|l -i_ '.11potqdbs >L 981 'C9 '29 'sflpolqauoopnasd 's€t 'r0 t '90I 'rot '1ot '66'96 '96't6 'snq|ou3r(lod l{l'Dlnltus 901 '66 'leolopnosd 0t S tlJ 'Z8t 'ttt 'b6'E6'68 'sapolltou8tlod gS srllJol8 8lJ'f8l '9 '8€I '18 'sn14slu.u{opnasd tod 'snpodoloJs SCS 181,66, 96' 68'98'oepqr€ua at 0t 9 3H 's8I 'Itt '8S 't 9 'SS '8I ',DulpolaqoPnasd Zt 'lt 'EecEqlguSlod TSoJCSnIu 5'aaptrEopodolols 6ZI rOlC?JlOrd 6L'snpolntuqod tu:E1r30tprullps fI 9 3!C '981 '19 'snpotuol.tdolord z 9 3lJ 's8l ',Etl ',6t ',gt ',snpouolod -tnIrDuStqdns * tz'snp$nuo^ 081 6/l euoclleclDlod IFeue eleqdscs gs 'snJupwtlt[sD 6/I 'sI05lDlod f mpoPuoJs 9 S 8lJ'S8I 't;'s potap odolotd ssl 'uoqsuroc lueseoldlulod adlDJS I}j'.nPo s8 J'29'oepquoporepu"doloJd 0t s 3td ',s8l ',ls ',ss',9l 'snttouSoSav \nqouSo!loJS E 98t 't9 '29'lS '9t 'Zt 'eprluoporepuDdolord 8l 'snpol.llodsonaH vlPprrqqors a ls 0s s 319'60I 'stllDrqapaord 981'€a oeplulpolceld EF qon$Od CS -rc ) 09 9'8lJ'III ' auqxt@w ,tl '16's1nl1al EI'.D) uO[rSOd qS .4c'zt os.s I 'lll 's.11.utoJi1pto2 l6'sEuaaalplo ft :rJnbes {n€s 3u '88t 'Itt'9Et'Ltt'|lt '6Ot 'snpoqtollSototd l6'lssolt 'sl,DSUOSad 09'9 99 lt 'sluopouocolold 16'DPlto[ E9'DtuuDuauuDs gtl .srseuoSord 16'srsualwlnq t'LnrrruopotlSos z s au '98t 'ztt 'tet '8, 'Lt '9, '9b 'snluopouoxotd /t s au 't8I '99t '9st 'E6't6 'eI,,'Dutpolrau,, I i-I'lF'on8os S8l'9t'eepquopouocora 16 EL',slnual rPrc) uo[$od ?S 98t '[fl 'St 'Zt 'epiluopouocord l6 'orDlsozora$odL r+ lo) uo[$od S zt 'eecEluopouocord rc'e L 'oplolf 9I'ssscoJd t6',s1tuaIlqllnq -t_ , .shttouBotslrd ,saploloalrDo t 89'snlqnp LBI 18 f.L -tutporDpunlov 19 €t 9 31J '98I 't't ',9L',59',tg ',29'snPoluolrd lEl 'EL 'Dpalfi)o 'lllnjlsod iol 98t '29 '98 'oep0uopoluoud tz'g '4J '!8pu ZOt Iersod 98r'9rr '98I'99t'9SI'SSI' t 't€I' t6'SL'E L' rZ'oulpopal4 ,n9'€9 rrpossox, 'ttt'Ect'81' LL'9L'69'6t'Sb'Zn'?pnuoporuoud LgI 'L8'snsot^itold tarDlsoJl ,sI ,suroJleld s tsnqov sr'zt'It'"oscluoporuoud 0z 1t qroJoqcu,{qu r/9I

otz INDEX 2tl

Rabeignathus,117, I19, 188,Fig. 5.56 Spathodus,ll5 5-47 Radular teeth, 172 Spathognathodontidae,89, 90, 91, 94, 95, 96, 97, 106, Ramiform element, 15, 16,24 tt2, t34, 116,t4t, 144,167, t87 Rastrat€element, 15, 18, 55, 57 Spathognalhodtls,ll5 Recapitulation,145 Spatula,I I ? Recurrentgroup, 39, 40, 4l SlauflercL\a,53,185, Fig. 5.5 Red River Province, 167 Staurcghathla,83, 84, 136, 187,Fig. 5.32 Rhachistognathus,97, 136, 137, l4l, 187,Figs. 5.39, Stellatepectiniform element,21 5.41 Steptotaxis,65,66, 186,Fig. 5.18 ) Rhipidognathidae,62,7 5, 99, 186 fumishi grotrp, l4l Rhrpidog4athu:,15,16, 155,156, 157, l86,Figs.2.ll, Steteocohtls,123, 188,Fig. 5.59 5.26 \ Stolodus,49, 185,Fig. 5.3 lzl l, 145, slmmetricttl;,l54 Sttuchahoghath s, 185 Rhodesognathui564,134, 156, 186,Fig. 5.16 Strcptognathodl,ts,ll4, ll5,137,146, 150,l6l, 163, Rhynchocoela,3l! 176, 182 188,Fig. 5.52,5.53 Robtglicoslatusstiock (of Polygnalhus),99,100, l0l Subbryantodus,I 15, 116, 188 t33,l4l, Rossods,53,60,61,133, 186, Fig. 5.12 Survivorship curves, 139 Rostral ridge, 102 Sweetina,85, 137, | 38, 187,Fig. 5.33 Rostrum, 102 Sw€erognathidae,90, 92,96, ll2,ll7, 188 Lll Rotundacodina,67, 68, 186,Fig.5.19 Sweetognathinae,I l7 dubius,68,7l,146 Sweelognathus,89, 117, l19, 137, 138, 188,Fig. 5.55 S position (or element),24,25, 30 menilli, l19,131 Sa position (or element),25 whitei,IL9,l2O Sagiua,41,174, l'l5 Symmetry,classes of, 25 45. Fis.5.2 Sagittodohtina,64, 67, t86, Fig.5.l5 Symmetry-tran$ition series, 22 Sannemannia,65, 66, 186 Synpioniodina, lO4 pesanses, 66 188.Fig. 5.50 Sauk sequence,132,133, 134 TanglewoodMember (of Lexington Limestone), Sb position (or element),25 155 Sc position (or element),25 Tangshanodus, 186 Scabbardella,53, 185,Fig. 5.5 Taphrognalhus,l2O, 122, l88, Fle. 5.57 rt5 kaliognath s, 33,84, 159, 187 Tenraculata. See Lophophorata Scalpellodus,54, 185,Fig. 5.7 Teridonlidae, 52 Scandodus, 54 Teridontus,45, 52, 5!, 133,142, 157, 185,Fig. 5.5 Scaphaleattachment s!fiace, 15,22 Tertiopedateramiform element, l7 Scaphignathus,96, 107, 123, l4l, 187,Fig. 5.41 Tethyan Prcvince, 168 Schmidtognathus,102, 104, 106, 135, 188,Fig. 5.47 Tippecanoesequence, 132, 134 Scolopodontidae,52 Tooth comb, 179 Fr. 5.10 Scolopodri, 53 Tortodus,93,94, 187,Figs. 5.39,5.41 13i gracilis,56 Ttiangulodus, T2 Sclttula, lO4 Trichonodello, 11 Scyphiodtu,73,'14, 143, 186 2expansa,68 primrs,74,Fig. 5.25 T gonodur,12 Sd position (or element),25 Trimembrate skeletal apparatus, 24 Secondaryprocess, 21 Tipodellus, IO5 ! Segminate pectiniform element, 22 Tripodontinae, 62, 186 sefitacon oaus,)2, )J, )o, t6), l.lg. ).) Tripodus,60,61, 62, 63,72,13,75, 133,14l, 185,Fig. [3,1.187 Septimembrate skeletal appamtus, 24 5.t2 al- lE7,Fig. Serratognalhus,53, 185,Fig. 5.6 deltotus, '12 Seximembrate sk€letal apparatus, 24 Trisegminiscaphate pectiniform element, 22 Siphonodella,89,96, 99, 106, 107, 108, 136, 188,Figs. I ropodus,)5, lu), nrg. ).) 5.48,5.49 complus,53 duplicala, 109 Truchercgnalhus, 79 pruesulcata,107, 108, 109 True conodonts,4l sulcato, 107, IO9 Siphonognathui, 106 Skeletalappararus, 23, 37, 38 Ulrtchodina,54, 185,Fig. 5.? Skeletalelemenl, 11 Unimembrate skeletal apparatus, 24 Solenogastres,172, 173 Utahfonus,53, 185,Fig. 5.5 Somites,29, l7l "Utica" Shale,155 -

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