New Crinoids from the Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula

Home , Articulata (Crinoidea), Cyrtocrinida, Holopodidae, Isocrinida, Isocrinidae, Notocrinidae

NEW CRINOIDS FROM THE EOCENE LA MESETA FORMATION OF SEYMOUR ISLAND, ANTARCTIC PENINSULA

TOMASZ K. BAUMILLER and ANDRZEJ GAZDZICKI

Baumiller, T.K. and Gaidzic ki, A. 1996. New crinoids from the Eoce ne La Meseta Form a tion of Sey mour Island , Antarctic Peninsula. In: A. Gaidzicki (ed.) Palae ontological Re sults of the Polish Antarctic Expe ditions. Part Il. - Palaeontologia Polonica 55 , 101-11 6. The exce llent record of marin e invertebrates from the Eoce ne La Meseta Formation of Sey mour Island (Antarc tic Penin sula) includ es several well-prese rved crinoids. Two cri noid species have been previously reported from the upper part of the La Meseta Form a tion; here we describe three addit ional taxa from the lower units (Telm l-2) of this forma tion: an isocrini d, Eometacrin us australis gen . et sp. n., a comatulid, Notocrinus seym ourensis sp. n., and a cyrtocrinid, Cyathidium holopus Steenstrup , 1847. These data are important in prov iding new infor mation for the time-envi ronm ent distribution of crinoids and for constraining phylogenetic hypotheses and evo lutionary scenarios . The co-occurr ence of these three taxa is unusual because sedimentological, stratig raphic, and paleoeco logical evidence suggests that the lower part of the La Meseta Formation was deposited in a shallow-marine setting whereas today, isocrinids, cyrtocrinids, and coma tulids eo-occ ur only in deep wate r. Also , the morphology of E. australis indicates that the syzyg ial articulation between the first and seco nd primib rachials, thought to represent a character of primary phylogenetic importance among the Isocrin idae, may have evo lved more than once. K e y wo r d s : Crinoidea , taphonomy, taxonom y, paleoecology, Eoce ne, Antarctica.

Tomas: K. Baumiller, Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02 138, U.SA Andrzej Gazdzicki, Instyt ut Paleobiologii PAN, Aleja Zwirki i Wigu/}' 93,02-089 Warszmva, Poland.

Received 23 Febr uary 1995. accepted 13 Se ptember 1995 102 TOMASZ K. BAUMILLER and ANDRZEJ GAZDZICKI

CONTENTS

Introduction 102 Acknowledgements . . 102 Geology and stratigraphy 103 Taphonomy . 105 Taxonomic methodology and terminology 106 Taxonomic descriptions . 106 Class Crinoidea MILLER, 1821 . 106 Subclass Articulata ZITIEL, 1879 106 Order Isocrinida SIEVERTs-DoRECK, 1953 106 Family Isocrinidae GIS LEN, 1924 . 106 Genus Eometacrinus gen. n. . . 106 Order Comatulida A.H. CLARK, 1908 . 110 Family Notocrinidae MORTENSEN, 1920 110 Genus Notocrinus MORTENSEN, 1920 110 Order Cyrtocrinida SIEv ERTs-DoRECK, 1953 11 2 Family Holopodidae ZITIEt, 1879 ... . 11 2 Genus Cyathidium STEENSTR UP in MICHAEl.I S and SCHERK 1847 11 2 Concluding remarks 11 3 References . 11 4

INTRODUCTION

Th e fossil record of artic ulate crinoids, a g ro up which includes all post-P aleozoi c crin oids, ex te nds back to the Tri assic, an interval during whi ch , or sho rtly before which, they origina te d (S IMMS and SEVASTOPULO 1993). Tod ay articulates can be subdiv ide d into three functio nal groups: those bearing sta lks through out ontogeny, the isocrinids, bourgu et icrin ids, and mill ericrinids, those which lose the sta lk as j uveniles and live as sta lkless, relative ly motile adults, the comatulids , and those which ce me nt the cup directly to the substra te, the cy rtocrinids . In modern oceans representati ves of these three fun ct ional gro ups eo-occur only in de ep wa ter since the cy rtocrinids and the sta lke d crinoi ds are res tricted to depths g rea ter than 100 m. The three crino ids described in thi s study, the co matulid Notocr inus seymourensis sp. n., the isocrinid Eometa crinus austra lis ge n. et sp . n., and the cy rtocrinid Cyathidium holopu s, all occur in the lower part of the La Meseta Fo rm ati on whic h, based o n sedimento log ic and paleontol ogi c crit eri a, has been int erp reted as representing sha llow-ma rine or even es tuarine se tti ngs . Thus in addi tio n to providing new taxonomic data re levant to o ur understanding of the evolutio nary history of crino ids , thi s study also helps con strain the timing of the previou sly documented offs ho re shift of so me crinoid lineages since the late Mesozoi c/earl y Cen o zoi c (e.g. BOTTJER and JABLONSKI 1988). The investi gated crino id collecti on is kept in the Institute of Paleobi ology of the Poli sh Acade my of Sci ences, War szawa under the ca talogue number ZPAL C a.v. Acknowledgements. - We thank Dave M EYER and Tat su o OJl for helpful di scu ssion s, loan s of Telm6-7 materi al , and ca reful reviews of the manuscript ; G. OZIEWI NSKA, F. D'EsCRIVAN , E. HAR A, G. LLEWELLYN, and A. PEI provided technical assistance for whi ch we are grateful. This study was funded in part by the Sh aler Fund (Harvard Un iver sity) and the Na tio na l Scien ce Fo undation, US A(EAR 93 04 789), the Institute of Paleob iol ogy, Poli sh Academy of Sciences (Warszawa), and the Al exander von Humboldt Foundati on (Bonn) . One of us (AG) is indebted to Professor Carlos A. RINALDI and Or. Rodol fo DE L VALLE (In stituto Antartico Arge ntino) for the invit ati on to join the Argentine Exp edition to Antarctica in the austra l sum mer of 199 3-1994 and to all colleagues fro m the field part y for assista nce in the field. Lo gi stic suppor t was provided by IAA (Buenos Aires) and Fuerza Aerea Argentina. NEW CRINOIDS FROM THE LA MESETA FORMATION 103

GEOLOGY AND STRATIGRAPHY

The La Meseta Formation, which crops out in the northeastern portion of Seymour (Marambio) Island is a sequence of richly fossiliferous, sha llo w-marine-estuarine, poorly cons olidated sands tones and silt stones, approximately 800 m thi ck (Text-fig . 1). Th e sedimentolog ical and stratigraphic fram ework of the La Meseta Formation has been described by RINALDI et al. (1978), ELLlOT and TRAUTM AN (1982), SADLER ( 1988), STILW ELL and ZINSM EISTER 1992, and POR F, BSKI ( 1995).

Cape Wiman

Lopez de Bertodano Bay

Penguin Bay

lkm o~--~

Fig. I Crinoid localit y index map of the La Meseta Formation 0 11 Sey mour Island. ZPAL I - Eometac rinus australis and Cyathidium holopus site. ZPAL 3 - Metacrinusfossilis site. ZPAL 6 - Notocrinus seymourensis site.

ELLlOT and T RAUTMAN (1982 ) init iall y subdivide d the La Meset a Form at ion into three informal members (Units I, II, and 1lI). SAlJLER ( 1988, fig. 1) mapped the La Meset a Formation and identified seven numbered lith ological units (Telm 1 through Telm7), whi ch demonstrate the lateral variability of the formati on . SAlJLER'S units are correlatable with the ones recogni zed earl ier by ELL/OT and TRAUTMAN (19 82) [see SADL ER (19 88, fig. 3) ; STILWELL and ZINSMEISTER (1992 , fig. 4)] . The La Meset a Form ation has been dated as Eocene to possibly early Oligocen e on the basis of fossil penguins (SIMPSON 1971 ), molluscs (Z INSME IST ER and CAMACHO 1980 , 1982), pol yd olopid marsupials (WOODB URN E and ZINSMEI STER 1982, 1984 ), and cetaceans (FORDYCE 1989). MAR ENSSI et at. (1994) determined that the middle part of the La Meset a Formation (Telm4-5) is middle Eocene based on correlation of terrestri al mammals found in these units with tho se from South Ame rica (Patagonia). Recent studies of marine palynomorphs (mostly din ofl agellate cysts) by ASKI Net al. ( 199 1), COCOZZA and CLARKE ( 1992), and BARNES and RIDI NG ( 1994) support an Earl y Eocen e age for the lower part of the La Meset a Fo rm ati on (Te lm l-2); a result that is co nsiste nt with ages o btained pr eviously by HARWOOD (1986,1988 ) and W RENN and HART ( 1988). Cr inoids whi ch have been pre viou sly described fro m the upp er part of the La Meseta Fo rmation (Telm6-7) include the isocrinid Metacrinus [ossilis (RASMUSSEN 1979; M EYER and 011 1993) and the 104 TOMASZ K. BAUMILLER and ANDRZEJ GAZDZICK I

Metacrinus fossilis

~ she lls 0.. pebbles D sand § sil t+ sand

Eometacrinus australis Notocrinus seymourensis

. . " , I . '.

1 ..

Fig. 2 Co mposi te strati gra phic co lumn of the La Meseta Form ation on Se ymour Island (South Sec tio n) showi ng the distribution of main lithofacies and location of crinoid sites. Section ada pted fro m SAIlLEK (1988). co ma tulid Notocrinus rasmu sseni (MEYER and OJI 1993). We report here three additional taxa from the lower part of the La Meseta Formati on (Telm 1- 2) which crops out so uthwest of Cross Valley near the L6pez de Bertodano Bay (Tex t-figs 1- 2) [see also Ge ol ogic al Map of Seym our Island in FELDM ANN and WOODBUR NE (1988)). Th e isocrinid Eotnetac rinus australis ge n. et sp. n. and the cy rto crinid Cyathidium holopus were collected at Bill Hill . locality ZPAL I [Text-fi g. I see also GAZDZI CKI and T AT UR ( 1994. pI. 2: 2)). The comatulid Notoc rinus seymourensis sp. n. was found at the locality ZPAL 6 (Tex t-fig. I). The Telm I crinoids, Eometacrinus australis and Cyathidium holopu s, occ ur within an up to 2 m thick interval of basal, transgressive facies represented in thi s area by grey to red -brown lim onitic, sandy siltstones, sandstones, and pebble conglomerates with intercalations of shelly hash. Crinoids represent NEW CRINOIDS FROM TH E LA MESETA FORMATION 105 only a sma ll portion of the total biota recognized in Telm I lithofacies sensu STILWELL and ZINSM EISTER (1992). They are associated with abundant cyclostome and cheilostome bryozoans which form multila mellar sph eroidal colonies up to 12 cm in diameter (G AZDZI CKI and HARA 1994 ; HAR A 1995), numerous brachiopods (BITNER 1996 this volume), stylasterids (STOLAR SKI in preparation), solitary and colonial minitrabecular corals (STOLARSKI 1996 thi s volume), gastropods, polychaete worms, asteroids, cidaroid echinoids (RADWANS KA 1996 this volume), gadiform fish remains, shark teeth, and characteristically large Ostrea and Pecten shells and shell fragments. Microfossils are represented by benthic foraminifera and ostracods. The comatulid, Noto crinus seymourensis, occurs in unit Telm2 which in the Cross Valley are a is characterized by laminated fine -grained sands, silty sands, calcareous siltstones, and cla y beds up to 250 m thick (STILWELL and ZINSM EISTER 1992). The two spec imens of N. seymo urensis were collected at locality ZPAL 6 (Text-fig. I) in the lower part of unit Telm2 (Text-fig. 2) from a calcareous sandstone lithofacies which also contained molluscs, echinoids , and bryo zoans. In addition to the faunal ass emblage, the pre sence of sedimentary structures such as flaser and wa vy bedding and climbing-ripple laminations indicate that the Telm I and the lowermost Telm2 lithofacies represent a nearshore, sha llow-marine environment with normal salinity.

TAPHONOMY

One of the more unu sual aspec ts of the crinoids from the La Meseta Formation is their mode of pre servation . For example, the comatulids hav e well-preserved, articulated arms and pinnules but the centrodor sal and cirri are poorl y preserved or missing (MEYER and OJI 1993; this study). Thi s is unu sual because normally the ce ntrodorsal is the only element that is fossili zed and recovered. Experiments on extant comatulids have revealed that the crown normally disarticulates qui ckl y and that in the process of post-mortem disarti culation a ch aracteri stic sequence is followed: the pinnules disarticulate first, followed by the cirri, the distal arm s, and finally the proxim al arms (LIDDELL 1975 ; D.L. MEYER and K.B. MEYER 1986 ; BAUMILL ER 1994). Thi s suggests that when arms and pinnules are found intact , they ou ght to be attac hed to the cen trod orsal. Th e mode of com atulid preserv ation in the La Meseta Formation is not con sistent with this prediction. It is likely that the se co matulids were buri ed qu ickl y, pos sibly wh en still alive. Th ey re mained intact during the process of bu rial, co mpaction, and fossil izati on ; the loss of the centrodorsal and cirri occurred after the specime ns were exposed on the outcro p. The mode of preservation of isocrinids in the La Meseta Forma tion also differs from that of oth er fossil isocrinids and from what wo uld be expec ted based on res ults of taphonomic ex perime nts (BAUM ILLER 1994 , in preparation ). Isocrinids possess articulatio ns specialize d for autotomy in the stalk, the sy nos toses/cryptosympl exies, and in the ar ms, the syzygies. Th e anima l ca n act ive ly shed parts of the skeleton at these artic ulations; thi s happen s whe n it is physic ally stressed by temperature or sa linity cha nges (BAUM ILL ER 1994 , in preparation) and by mech anical stimulatio n (OJI and O KAMOTO 1994). Furthermore, these articulat ions represent planes of weakn ess du ring post-mort em transport or decay, i.e., carcasses disarticul ate first along autoto my planes, and only later along other articulations. As in comatulids, there is a charac ter istic disarticul ation sequence (BAUM ILLER 1994 , in preparati on); failure occ urs in the foll ow ing order fro m first to last: distal-most syzygies, pinnules, med ial syzygies, proxim al syzygies, sta lk synos toses, cirri, proxim al co lumna ls, radia ls, and basals. The reason that proximal columna ls remain attac hed to the basals and radi als lon ger than other ske letal eleme nts is that the proxim al sta lk lacks synos toses - these develop between nodals and infranod als several ce ntime ters below the base of the cup (LLEWELLY N and BAUMILL ER 199 3; BAUMILL ER 1994, in prep aration). The pre servat ion of Eometa crinus australis (this study) and Metacrinu s f ossilis (M EYER and OJI 1993; this study) with articulated crowns, articulated pinnules but lacking attac hed sta lks is highl y unu sual. MEYER and OJ! (1993 ) noted this peculiarity in M. fo ssilis from Telm6-7 and suggested that it ind icates shedding of the stalk by juvenil es, and a free- liv ing, co matulid-like adult existence. A similar inference could be made about E. australis since it is also preser ved without sta lks attached. However, the presence of adult-s ized pluricol umnals in proximit y of the cro wns, argues aga inst such an interpretation and suggests that E. australis retained its sta lk through adulthood but that its loss preceded buri al. 106 TOMASZ K. BAUMILL ER and ANDRZEJ GAZDZICKI

TAXONOMIC METHODOLOGY AND TERMINOLOGY

The taxonom y of crinoids is co mplicated by the fact that these animals possess multiplated skeletons which disarti culate readily after death ; what we recover as fossils are typ ically the animals' fragmentary remai ns. The definiti on of spec ies based on fragm ents can lead to a proliferation of taxa as different fragm ent s of a single anima l may be used for designating new species. Th is is especially probl em atic whe n sta lk element s (co lumnals) are used to define taxa because co lumnal morphologies vary greatly within indivi duals and between indi vidu als of the same spec ies. In our treatm ent , we have tried to avoid using frag ments for erecting new taxa. Anoth er problem posed by the low preser vation potenti al of co mplete crinoids is the incompatibility of spec ies and generic definiti on s of Recent and fossil organis ms . Th e monument al effort of A.H. CLARK (1908, 1923) during the first half of thi s ce ntury resulted in the publication of his multi-volume work on extant co matulids in which he described over 100 ge nera basing his definitions on minute differ ence s, such as in the morphology of pinnules and cirri. Sin ce neither pinnules nor cirri are co mmo nly foss ilized, the criteria used for distin gui shing Recent taxa are largely inapplicable to fo ssil s. In fact , mo st of the co matulid fossil record is represent ed by ce ntrodorsals only and differences in ce ntrodorsa l morphology are used to differenti ate amo ng fossil comatulids. Th e co ntrasting criteria have hindered a uniform taxonomi c treatment of co matulids. Th e comatulids of the La Meseta Formation represent unu sual fossil s: the arms and pinnules are in a better state of preser vation than the ce ntrodorsal. Thi s mode of preser vation allows so me co mpariso ns of co matulids fro m the La Meseta Formation to other fossil taxa based on the ce ntrodo rsal and also provides some means, based on the morphology of the arms, for co mparing them to Recent taxa. In the taxonomi c treatm ent of cri noids fro m the La Meseta For mation we use differences in discrete character states for discriminating cri noi d ge nera.We define a cri noid ge nus as co nsisting of individuals sharing a unique co mb inatio n of discrete, rather than co ntinuous, characters; differences in discrete characters reflec t large morph ological discontinuities and minimize the potential for error in identi fication . Using the above defin ition , the ge nus Eometacrinus, for example, includes those isocrinids possessin g a synarthry between the first and second primibrachia l and a muscular articulation between the first and second sec undibrachia l. Our treatm ent of spec ies allows for the use of objective definiti ons based on differences in continuous characters. In term inology, we follow the Treatise 0 11 Invertebrate Paleontology (BREIM ER 1978).

TAXONOMIC DESCRIPTIONS

Class Crinoidea MILLER , 1821 Subclass Articulata Z ITTEL, 1879 Order Isocrinida SIEVERTS-DoRECK , 1953 Family Isocrinidae GI S Ll~ N . 1924 Ge nus Eonietacrinus gen . n. Type species: Eometacrinus australis gen. et sp. n. Derivation of the name: From the Greek eo - dawn. earliest. oldest. Diagnosis . -Isocrin idae with a synarthrial IBr l_2' muscu lar 118r '_2' and typ ically 5 primibrachia ls. Remarks. - Th is ge nus possesses an un usual co mbination of prox ima l brach ial artic ulat ions: a sy nart hry at IBr l_2 and a muscular articulation at 118r l_2' These characters are thought to be of pri mary phyloge netic importance and have been used to subdivide the Isocrinidae (011 1985; SIM MS 1988). OJI (1985 ) included all isocrinids with a sy nart hry at IBr '_2 in his "old group" and all those wit h a syzygy at IBr l_2 in his " new gro up" . S I1\ IM S (1988) used the 118r l_2 articulation to furt her subdivide OJI 'S"new gro up": he placed taxa with syzygies at IBr ' _2 and synart hries at 118r l_2 in one group and those with syzygies at IBrl _2 and IIBr' _2 togeth er with the extant ge nera Metacrinus and Sara crinus in anothe r. In Metacri nus and Sara crinus, however, IBr' _2 is syzygial and IIBr' _2 mu scul ar. Eometacrinus resembles Metacri nus and Saracri nus in having more than two primibrachials and a mu scul ar articulation at IIBrl_2: NEW CRINOIDS FROM THE LA MESETA FORMATION 107

Eometacrinus is therefore assumed to have close affinity to these two extant taxa. In pos sessing a synarthry at IBrl_Z' however, Eometacrinus resembles members of OJI'S "old group". Given the above, it is likely that the Eometacrinus-Metacrinus-Saracrinus lineage and the "new group" represent independent off shoots from the "old group".

Eometacrinus australis sp. n. (PI. 27 : 3-8; Text-fig. 3-6)

1994. Metacrinus sp.; B AUMILLER and G AZDZI CKI , fig. 2A.

Holot ype : ZPAL Ca.V/ I. Type horizon: Telml , La Meseta Formation (Eoce ne). Type localit y: ZPAL I (Bill Hill), Seymour Island , Antarctic Penin sula. Deri vation of the name : From the Latin australis - southern. Diagnosis. -As for the genus. Material. - Three crowns: one with radials and brachials throu gh pentibrachs, the second with radials, basals, and brachials through tetribrachs, and the third with the most proximal columnal, basals, radials, and brachials through tetribrach s. Thirty four pluricolumnals, 2 to 22 columnals long . Description. - Dorsal cup bowl-shaped and low with a nearly flat base. Basals small, rhombic, 1 mm high and I mm wide , tumid, and with lower edges distinctly downward protruding over the uppermost columnals; separated from each other on dor sal surface by a gap exceeding their width. Radial s very low, approximately 2-3 time s wider than high; width 4-5 mm (Text-fig. 3). Five primibrachials. Suture between the radial and the first primibrachial strongly concave down. First primibrachiallow, 4-5 times wider than high . IBr,_z synarthrial. Synarthry with a well-developed central ridge (4 mm in length and 0.3 mm wide ) with a large central canal, 0.4 mm in diam eter; ligament fossae deep and symmetrical around the ridge. Second and third primibrachi als 2-3 time s wider than high . IBrZ_3 and IBr3-4 oblique muscular. Fourth primibrachial low, 4-5 time s wider than high . IBr4_5 cryptosyzyg ial or synosto sial, tightl y fused and showing nearl y straig ht suture on dorsal surface. The arm s are divided isotomously as many as 4 times; arms more slender towards distal ends, but almo st uniform within each brachitaxis. Axillarie s nearly triangular; their distal articular faces form an angle of ap proximately 60° with the axis of the arm; 1.5 time s wide r than high. Between 7 and 9 secundibrachials. Syzygial or cryptosyzygial articulations: IIBr3-4' IIIBr3-4' IYBr3-4' and YBr3-4' Brachi als smoo th, 2-3 times wider than high proximally but becoming higher than wide distally; quar E tibrachials 1.2-1 .5 times higher than wide. First pinnules E .,..., on IBrz. First pinnular as wide as high , slightly flared at both end s. Pinnular face t with a ce ntral, narrow fulcral ridge. Only single columnal found attached to one of the spe cimens; pentastellate; length from margin of radiu s to mar gin of opp osite interradiu s, 4.0 mm. Lumen circular, 0.4 mm in diameter. Pluri columnals numerous, from 2 to 22 columnals long. Nodals and internodals of subequal dim ensions. Interno dais pentagonal to rounded subpentago nal in outline; no dais more pentalobate. Internodals average 4.6 mm in diameter (range: 3.9- 5.4 mm) and 1.3 mm in height (range: Fig. 3 1.1-1.5 mm). Nodals slightly greater in height , but not Camera lucid a drawing of cup plates and proximal brach ials of Eometacrinus australis gen . et sp. n. significantly different in diameter. Two complete nodi taxe s b - basal ; R - radial; 1-5 - first through fifth with II columnals per noditaxi s; two pluricolumnals lack primibrachials; single arrow - syzygy; doubl e arrow ing nodais with 12 internodals. Cirrus scars always five in - sy narthry; all other artic ulations - muscul ar number, directed outward and slightly upward; of moderate (ZPAL Ca.V/3) . 108 TOMASZ K. BAUMILLER and ANDRZEJ GAZDZICKl

Fig . 4 The synarthrial articulation at IBr l - ~ in Eometacrinus australis gen. et sp. n. Arrows poi nt to synarthrial ridge . a - ZPAL Ca .V/2, X 10 ; b - ZPA L Ca .V/3 , x 10. size (34- 44 % of nodal diameter), occ upying the entire height of the nod al but not impingin g on infra- or supra-nodals; weakl y depressed and elliptical in outline. Articular ridge of cirrus soc ket straig ht with the long axis perpendicular to columnal axis; close r to the supra -nodal than the infra-nodal margin of the socket. Ends of ridge slightly raised; ca nal subci rcular. Proxim al cirra ls (only two present ) low and disc shaped; circular to slightly oval in outline with a raised outer rim. Articular ridge also raised and displaced upwards. Articulation betw een nodal and infranodal synostos ial or cryptosyrnplectial; nodal articulum slightly co ncave and faintly petaloid. All other articular facets symplectial. Elliptical areo la surrounded by moderate sized culmina reac hing their maximum length a th ird of the distance between the margin and the lumen and oriented at a slight angle to each other. No radial space but a radial groo ve may be developed. Number of culmina per petal fairly constant: 3-4 adradially and 4-6 margin ally, Lumen small (0.3 mm in diameter on a columnal of 4.3 mm diameter) and round. On cryptosy mplectial articulation s lumen genera lly occluded (on 8 of 8 nod als and 8 of 9 infranodals). Latera straight but may be slightly inflated into rounded, faint epifacets. Remarks. - The specimens of isocrinids found in Telml of the La Meseta Formation are exce llently preserved and, based on the characters of the crow n and stalk, belon g to a single species. The presence of 5 primibrachials in all specimens distingui shes them from the vast majorit y of known isocrinids which possess only 2 primibrachi als; onl y Metacrinus and Saracrinus have 4 or mor e primibrachials. According to CLARK (19 23) spec ime ns with 4 primibrach ials are ass ignable to Saracrinus while those with more than 4, typically 7, to Metacrinus. Although OJI (19 86) has shown that the number of primibrachi als in extant members of these two genera can be vari able , he retained CLARK'S sche me. Th e 5 primibrachials of the Telml isocrinids fall within the range encountered in Metacrinu s but because of the pre sence of synarthries rather than syzyg ies at IBr'_2' they are assigned to Eometacrinus. In 1979 RASMUSSEN describ ed a new isocrinid spec ies , Meta crinus fossilis, fro m the Telm6-7 of the La Meseta Formation and more recently MEYERand OJl (1993) reported numerous well-preserved cro wns of M. [ossilis from the same localit y, A re-examination of some specimens described by M EY ER and OJl and of additional crowns co llected by one of us (AG) from Telm6-7 revealed striking similarities between NEW CRINOIDS FROM THE LA MESETA FORMATION 109

35 ,...

30 -

25 - ,... I-< s:~ 20 - S ::l Z 15 - ,... ,...

10 - -

5 - r-

o n IIIIn I I • 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Number of secundibrach ials

Fig. 5 The number of secundibrachials in Eometacrinus austra /is gen. et sp. n. (Telm I ; solid bars) and Metacrinus foss ilis (Telm6-7; open bars).

8-.------,

7 - o o 0 o 0 o o 6 - o o 000 ~O DD o BOtt 5 - B [j1J 0 et]!1:I0 0 0 o o 0 ~ 0 -1:1I 0...... 0L..D"O 0 0 _ .0_ 4 - o - o~ 0 o 0

2-+------.-I - - - - - ,--I ------.---I ------i 1.5 2 2.5 3 3.5 Height (mm)

Fig. 6 Shape of axillaries in Eometacrinus australis gen. et sp. n. (Telm l; solid squares) and Metacrinus fossilis (Telm6-7; open squares).

Metacrinus fossilis and Eometacrinus aust ralis. In the shape of the crown, shape and size of basals and radials, and number of prim ibrachials the two species are very similar to each other, in fact the specimens of E. australis were referred to Metacrinus sp. ( BAUM IL LER and G AZDZ ICKI 1994) before additional preparation exposed the distal facet of IBr, (Text-fig. 4). Thi s facet in E. australi s is a synarthry whereas in M. fossilis it has been described by R ASMUSSEN (1979 ) and M EYER and OH (1993) as a synostosis. As 110 TO MASZ K. BAUMILLE R and AND RZ EJ GAZDZIC KI the latter two authors noted however, the lBrl_2 "suture has sma ll ridge-like projection s, similar to synarthrial artic ulations" (MEYER and 011 1993, p. 253 ). Indeed , a re-ex amination of lBr'_2 sutures in M. fossilis co nfirmed their enigmatic natur e: they are slightly co ncave distall y and a ridge-like proj ection is visible in some spec imens. In the one spec imen with the distal facet of lBrl ex posed, however, ther e is no sign of a dorso-vent ral ridge; this may be a preservational artifact, however, as the articulatio n is poorl y preser ved . Ano ther imp ort ant di fference between M.[ossilis and E. aust ralis relate s to the stalk. No pluricolumnals have been found assoc iated with M. fossilis and the stalk segments attached to the crowns are typicall y very short (the longest segment reported is 3 1 mm lon g) and distall y tapering while 34 pluricolumnals were co llected with the three crowns of E. australis. Althoug h the stalk materi al is isolated and all E. australis crowns ge nera lly lack co lumnals, our design ation of the pluricolumnals as E. australis is based on ( 1) the eo-occ urre nce of plurico lumnals and crowns and the fact that E. australis is the only isocrinid recovered fro m the Telm 1 loca lities, (2) the morphology of the cirrals: cirra ls found with the crowns match closely the two pluricolumnal cirrals in gene ral outline, size and shape of the fulcrum, and the po sition and size of the central can al. Althoug h the sing le co lumnal att ached to the crown of E. australis is smaller in diam eter, more pent aste llate than those in the isolated material, and has a slightly larger lumen , this is con sistent wit h the differences betwe en prox imal and distal co lumnals in oth er isocrinid species . There are oth er, min or, differences between the Telm 1 and Telm6-7 isocrinid s. For example, the number of sec undibrac hials is ge nerally lower in E. australis than in M. fossilis (Text-fig. 5) and its ax illaries have a grea ter height-to-width rati o (Tex t-fig. 6).However, both cha racte rs ca n vary within individuals and within spec ies and their taxonomic value is uncertain . Given the level of morphological similarity, and geo gra phic and temporal proxim ity between E. aust ralis and Mifossil is, there can be little doubt that they are closely related . In fact , it is only the appare nt difference in lBrl_2 that justifies assigning them to separate ge nera; until appro priate mater ial bec omes ava ilable to co nclus ively determ ine the nature of lB rl_2 in the Telm6-7 isocrinids, we favor retaining them within M. fossilis. Occurrence. - Seymour Island, La Meseta Formatio n: ZPAL I (Bill Hill), Telm 1 (Eocene) .

Order Comatulida A.H. CLARK, 1908 Family No tocrinidae MORTENSEN, 1920 Genu s No tocrinus MORTENSEN, 1920 Type species: Notocrinus virilis MORT ENSEN, 191 7. p. 206.

Notoc rinus .\·c Y II/O /l rensis sp. n. (PI. 27: 1; Text-figs 7- 8) 1994. Notocr inus sp.: B A U ~lI LL E R and G Aznzl cK I, fig. 2C.

Holot ype: ZPAL Ca.V/5 . Paratype: Z PAL Ca .V/6 . Type hori zon: Telm2. La Me set a For ma tion (Eo cene) , Type local ity: ZPAL 6. Seyrnour Island . Antarctic Peninsula . Deri vati on o f the name: From Seymo ur Islan d . where the specimens were found. Diagnosis. -A small Notocrinus with radi al havin g small or no free dorsal surface and radi al edge projecting down ward in midradial area between the up permost cirrus sockets. Material. -Two crowns on a single block of sandsto ne. Th e holotype with on ly a porti on of ce ntro dorsal and arti culated ann seg ments 1- 1.5 cm lon g; the paratype with a ce ntro dorsa l distorted by com pression . several cirri, and only the most proxi mal brachi als. Description. - Ce ntrodorsa l conical to subconical: sides straight to ge ntly co nvex. Dorsal end not ex posed. Dimen sion s of ex posed part of ce ntro do rsa l: maximum width about 2.6 mm at the level of rad ial s, height about 2.4 mm . Cavity ex posed at level of radi als in abraded specime n; 0.6 mm in diameter. Sides of ce ntro dorsal covered by fairly large cirrus sockets; on the single, clearl y expo sed radi al area of ce ntrodo rsa l, sockets not arra nge d in distinct co lumns or rows, closely spaced. Sockets circular, smooth, no articular rid ge , no cre nellae , rel atively sha llo w, with a small axial pore . NEW CRINOIDS FRO M THE LA MESETA FORMATION III

Cirri more than XXV, shor t, stout, and stro ngly curved; longest, incomplete cirrus 8.5 mm . Cirrals smoo th, cy lindrical, varying in shape: several proximal ones shor ter than wide (diame ter 0.5 mm , len gth 0.3 mm ) med ial slightly longer than wide (dia meter 0.5 mm , length 0.7); distal cirra ls and term inal claw unknown . Basals not visible on free surface . Radials as high as wide (1.5 mm ) with no distin ct free surface. Ventral edge of radial not straight but projects downward in the mid-radial area between the upp er most cirrus sockets. Articular face t almos t flat, very steep, but thi s may be in part due to distortion of specimen. Dorsal ligament fos sa large with a distinct ligament pit. Central ca nal large and subcircular in outline. Articular ridge reaches the interradial areas ju st above the ce ntrodorsal. Ridge well-develope d and nearly stra ight with the distal ends curvi ng slightly dorsall y. Brach ials with smoo th free surface. IBrl rec tangular and low; width 1.5- 1.8 mm , height 0.4-0.6 mm (Text-fig. 7). IBr ' _2 synarthrial. lB r2 axi llary, nearly triangul ar; proxima l edge co ncave with central region slightly prot ruding down to synarthria l node; distal articular faces slightly co ncave, form an angle of abo ut 0 60 ; height 1.1- 1.3 mm, width 1.6-2.1 mm. First secundibrac hial lower than the second: IIBr , width 1.1-1 .3 mm , height of abradia l sides 0.4-0.5 mm ; IIBr2 width 1.2-1.4 mm , abradia l heigh t 0.6-0.7 mm . Proxim al articulation of IIB r l muscular, distal articulation synarthria l with node on IIB r2 well developed . IIBr2_3 muscular. Syzygies at IIBr3-4 and IIBr9_' 0; brach ials of syzygial pairs app roxim atel y equidimensio nal. Firs t pinnule on IIBr2' abra dia l. Only few proximal portions of pinnules preserved ; segments smoo th, rounded, and stout. First two pinnulars: width 0.3-0.4 mm , height 0.3- 0.4 mm. More distal pinnulars not preser ved . Arm length indeter minate; distance bet ween IBr '_2 and IIBrl3_1 4' about 10.5 mm. Remarks. - Th e taxonomi c ass ignment of the Telm 2 eo matul ids is difficult because of their poor preser vation : the inde ter minate nature of the dorsa l and ventra l sides of the centrodorsal hind ers co mparison to fossil co matulids while lack of co mp lete pinnules and cirri inhibits assignment to Recent taxa. Nevertheless, there are enough characters present on the two speci mens to con clude that these comatulids are ass ignable to the genus Notocrinus; these characters include the co nical ce ntro dorsa l, sockets lack ing ornamentation, sto ut cirri and arms, stee p and flat rad ial face ts (Text-fig . 8). A recently described comatulid from Telm 6- 7 of the La Meseta For mation, Notocrinus rasmu ssen i M EY ER et OJI, 1993, differs sign ificantly from the Telm2 co matulids de scribed herein . The most obvious difference is its size : N. rasm usseni is much larger than N. seymourensis such that in the former the distance between lB r l_2 and IIB r3-4 is 5.0 mm , while in the latter it is 2.5 mm . In addition to the size dif ference, the two differ in the shape of brach ials. Wherea s in N. rasmusseni the first prim ibrachi al (IBr,) is trapezoid al and the second primibrach ial (lBr2) pentagonal, in N. seymouren sis the former is rectangular while the latter more triangular than pent agonal. The shapes of distal brach ials also differ being more wedge-shaped in N. rasmusseni. Given these dif ferences, the ass ignme nt of the Telm 2 and Telm 6- 7 comatu lids to a separate taxon see ms justified. In fact , the mor pho logy of N. seymourensis is more like that of the extant species Notocrinus mortenseni JOHN , 1938 than that of N. rastnusseni, Fig. 7 The small, co nical centro dorsal, the shor t, curved cirri with Camera lucida drawing of prox imal arms of No rounded seg me nts, the robust ar ms with syzygies at IIB r3-4 tocrinus seymourensis sp. n. I - first primibra and IIBr 9_IO' and the stout, rounded pinnules are characters chial; 2 - secon d primibrachial; all other bra chials - secu ndibrachials : dotted lines - in shared by N. seymourensis and N. tnortenseni. N. seymouren ferre d plate edge ; stippled plates - pinnul ars; sis, however, possesses a unique suite of characters distin single arrow - syzygy; do uble arrow - sy guishing it fro m N. mortenseni and other Notocrinus, includ narthry; all other brachial articulations - muscu- ing a concealed free surface of the radia l, a near-vertical radial lar (ZPAL Ca.V/5) . 112 TOMASZ K. BAUMILLER and ANDRZEJ GAZDZICKI

Fig. 8 Notocri nus seymourensis sp. n. Side view of crown with centrodorsal and exposed radial facet. Paratype ZPAL Ca.V/6. x 6. facet, and a downward proj ecting ventral edge of the centrodorsal separating the upp ermost cirrus sockets; in fact, these characters are reminiscent of Paleogene Conometridae such as Bru enn ichometra and Cype lometra, espec ially the Patagoni an, Miocene co matulid, Cypelometra iherin gi DE LORI OL, 1902. Only the centrodo rsa l of thi s ge nus has been described and in its shape and size it is not unlike N. sey mourensis. Unlike N. seymourensis, however, the cirrus soc kets in C. iheri ng i form 10 columns which are separated by a socket-free, vermiculate radial area. RASM USSEN (1978 ) placed C. ihe ringi and other mem bers of the Co nometr idae within the Tropiorne tracea because of the resemblance of their centrodo rsa ls and radi als. Th e prism atic, ca rinate pinnules, expose d basals, and generally more than 10 arms of the Tropi ometracea do not support a close re lationship between thi s famil y and the Telm2 co matulids . It is prob able that C. iheringi , and possibl y the rest of the Conometridae, are more closely related to the Telm2 co ma tulids and are thu s members of the No tocriniacea and not the Trop iometr acea; the lack of information on cirri and arms in C. iheringi and the Co nometridae hinders a definite resolution of thi s issue. Occurrence. - Seymo ur Island , La Meseta Format ion : ZPAL 6, Telm 2 (Eocene) .

Order Cyrtocrinida SIEVERTS-DoRECK, 1953 Famil y HoIopodidae Z ITTE L, 1879 Genu s Cya thidium STEENSTRUP in MICHAELI S and SCH ERK 1847 Type species: Cya thidi um liolopu s STEENSTR UI' in MICH AE LI S and SCHERK 1847.

Cyathidium holopus STEE NSTR UP in MICH AELI S and SCHERK 1847 (PI. 27: 2) 1847. Cyathidium holopu s: STEE NSTR UI' in MICH AELI S and SCH ER K. pp. 119. ISO. 1853. Microporocrin us Gastaldii: MICH ELl N. p. 93. 1884 . Cyat hidium ; CARPENT ER, pp. 143. 202. 211- 216. 1899. Cyat hidium holopu s; HENNICi. p. 11 6. fig. 2 1. NEW CRINOIDS FROM THE LA MESETA FORMATION 113

1913. Cyathidium holopu s: NIELSEN, pp . 19,27,39,56; pI. 4: 1-20; pI. 5 : 1-43; text-figs 17-20,31 ,33-34. 1930. Cyathidium sp.; K UHN, p. 548. 1930. Cyathidium holopus; RICHTER, p. 64 . 1961. Cyathidium holopus; RASMUSSEN , p. 242; pI. 35 : 1-10. 1994. Cyath idium ; BAUMILLER and GAZDZI CKI , p. 10, fig . 2B.

Description. - Rigid theca, presumably composed only of radials, with no apparent sutures. Cup irregular conical, tapering towards base. Wide articulations for arms separated by small triangular projec tions at interradii. The 5 primibrachials and 10 secundibrachials form a solid dome over the theca, Surface of plates unornamented and smooth. Each ray with single axillary primibrachial; primibrachial wide and pentagonal in outline (6.2 mm high and II mm wide at its base). Primibrachial may be composed of two fused primibrachials, but no evidence of this can be seen. Distal end of each primibrachial consists of two articulations for the secundibrachials oriented at an obtuse angle to each other. Length of articulations between primibrachials and secundibrachials averages 6 mm; width averages 1.7 mm. Proximal articular facet between primibrachial and secundibrachial muscular, sloping gently inward with faint, long, narrow fulcral ridge positioned closer to adoral than aboral surface of primibrachial. Small circular lumen of the axial canal situated just adoral to fulcral ridge; aboral side with elongated, elliptical ligament pit. Secun dibrachials triangular; rather large , 6.0 mm average width and 8.8 mm average height. Surface finely granulate. Joint faces between adjacent secundibrachials covered by crenellae. Specimen strongly com pressed laterally. Total height, 35.3 mm, maximum width at level of primibrachials, 24.1 mm, minimum width, 10.83 mm ; difference in width due to distortion caused by compression. Shape of upper edge of cup highly distorted due to compression. Articular facets not observed. Remarks. - Like all holopodid cyrtocrinids, which are adapted for cementation on hard substrates, the specimen from the La Meseta Formation lacks a stalk: its dorsal cup consists of fused radials attached directly to the substrate. Unlike the only other holopodid, Holopus, the La Meseta Formation specimen has only 15 exposed brachials (5 primibrachials and 10 secundibrachials) forming a complete covering over the ventral side of the theca. Its rounded, thin-walled theca distinguish it from the Cretaceous holopodid Cyathidium senessei, and its large size, smooth plates, and narrow base from Cyathidium depressus. Occurrence. - Seymour Island, La Meseta Formation: ZPAL I (Bill Hill), Telml (Eocene). Danian of Denmark, Sweden and ?Austria; Maastrichtian of the Netherlands.

CONCLUDING REMARKS

The crinoids from the La Meseta Formation described above provide information relevant to several paleontological problems. For example, today comatulids are diverse and common in shallow-water, reef settings while all other groups have low diversities and are restricted to water deeper than 100 m. This pattern of distribution and diversity is not mirrored by the fossil record however: in the fossil record comatulids are sparse and their diversities low, and throughout most of the Mesozoic stalked articulates are often associated with shallow-water deposits. Since these patterns can be susceptible to certain biases, one goal of crinoid research has been to determine whether they are accurate. If the patterns are accurate, additional questions arise: When did changes leading to the differences in diversity and distribution between Recent and fossil articulates occur? What caused these changes? The diversity of comatulids in modern oceans is well documented (RASMUSSEN 1978) but given their preference for reef environments, which are poorly sampled in the post-Paleozoic fossil record, their low resistance to transport and post-mortem disarticulation, and a difference in the taxonomic criteria used for recognition of living and fossil taxa the comatulid fossil record is likely to be very incomplete. Thus we can have little confidence in direct comparisons ofdiversity between the neontological and paleontological records. This limitation can be overcome only by quantitatively evaluating the taphonomic biases, expan ding the fossil data base, and establishing uniform taxonomic criteria for fossil and Recent forms. The La Meseta Formation crinoid, Noto crinus seymourensis sp. n., described in this study, augments the extremely depauperate Cenozoic record of comatulids and, in having pinnules, brachials, and cirri preserved together 114 TOMASZ K. BAUMILLER and ANDRZEl GAZDZICKI with the centrodorsal, possesses char acters that are taxonomic ally useful for both Recent and fossil comatulids. The shift of stalked crinoids into deep water during the post-Paleozoic is a pattern that is not subject to the same biases as comatulid diversity and one that has been much better established. The presence of stalked crinoids in shallow-water settings in ancient rocks and their absence from shallow depths today indicates that their distribution must have changed through time; this interpretation could be in error only if the environm ents of deposition of fossils had been misinterpreted or the carcasses had been transported into shallow water settings, both unlikely scenarios. A question that remains relates to the timing of the shift of stalked crinoids into deeper waters. Work by BOTTl ER and J ABLONSKI (1988) demonstrates that for isocrinids in the Euramerican Region the shift started by the Early Cretaceous and was essentially complete by the Eocene, but whether the timing of the shift was synchronous globally is still uncertain. In spite of the much greater robustness of the isocrinid pattern of distribution, new data on fossil occurrences, especially outside the Euramerican Region , help constrain the timing of the environmental shift and narrow the range of hypotheses about causes for the shift. The presence of Eometacrinus australis gen. et sp. n. in the lower part of the La Meseta Formati on provides new information on the temporal-en vironmental distribution of isocrinids, and demonstrates that outside the Euramerican Region isocrinids were still found in shallow- water settings during the Eocene (see also MEYER and OH 1993). Also, data on the morph ology of E. australis is relevant to the evolution of synarthrial and syzyg ial articulations between the first and second primibrachial, a character thought to be of primary phylo genetic importance (OH 1985 ; SI MMS 1988) and used to subdivide the isocrinids into two major subgroups. Finally, this study provides additional information on the stratigraphic and geographic distribution of the cyrtocrinid, Cyathidium holopus heretofore known only from the Cretaceous: the La Meseta Formation specimen represents its southernmost occurrence and extends its range into the Tertiary.

REFERENCES

ASKI N, R.A., ELL/ OT, D.H., STILWELL, 1.0. and ZINSM EISTER , WJ. 1991. Stratigra phy and paleon tology of Campanian and Eocene sediments, Coc kbum Island, Antarctic Peninsula. - Journal ofSouth American Earth Science 4, 99- 117. BARNES, R.P. and RIDI NG, LP. 1994. Angular unconform ity between the Lopez de Bert odano and La Meseta For matio ns (Ca mpanian-Maastric htian and Eoce ne), Coc kburn Island , northern Antarctic Peninsula. - Journal ofSouth American Earth Scienc es 7, 35--44. BAUMILLER, T.K. 1994. Impli cations of stress induced shed ding body parts in crinoids. - Geological Society ofAmerica, Abstracts with Programs 26 (7), A428 . BAUMILLER, T.K. and GAZDZICK l, A. 1994. Crinoids from the lower part of the La Meseta Formation (Eocene) Antarctica. - XXIPolar Symposium, 9-13. Warszawa, Poland. BITNER, M.A. 1996. Brachiopods from the Eocene La Meseta Formation of Sey mour Island , Antarc tic Peninsul a. In: A. Gaidzicki (ed.) Palaeontological Result s of the Polish Antarctic Expeditions. Part 11. - Palaeontologia Polonica 55, 65- 100. BOTTlER, D.l. and l ABLONSKI , D. 1988. Paleoen viron mental patte rns in the evo lution of pos t-Paleozoic benthic marin e invertebrates. - Palaios 3, 540- 560. BREIM ER, A. 1978. General morphology, Recent cri noids . In: R.e. Moore and e. Teichert (eds) Treatise on Invertebrate Paleontology, Part T, Echinodermata 2, T9- T58. Geolog ical Society of Ameri ca and Unive rsity of Kansas Press, Lawrence. CARPENTER , P.H . 1884. Report upon the Crinoidea collected du ring the voyage of H.M.S. Challenger du ring the years 1873-1 876.- Report of the Scientific Results of the voyage of H.M.S. Challenge r, 1--442. CLARK , A.H . 1908. New genera of unstalked crinoids . - Biologica l Society of Washingto n, Proceedings 21, 125-1 36. CLARK , A.H. 1923. A revision of Recent representatives of the crinoid family Pentacrinid ae, with diagnoses of two new ge nera. - Journal ofthe Washington Academy ofScience 13, 8- 12. COCCOZA, e. and CLARKE, e. 1992. Eocene micropl ankt on fro m La Meseta Formation, nor thern Seymour Island. - Antarctic Science 4, 355-362. ELLlOT, D.H. and TRAUTMAN, T.A. 1982. Lower Tertiary strata on Sey mour Island , Antarctic Peninsula. In: C. Craddock (ed.) Antarctic Geoscience, 287-297. University of Wisconsin Press, Madison. FELDMANN, R.M. and WOOD BURNE, M.O. 1988. Geo logy and Paleont ology of Sey mo ur Island , Antarc tic Peninsula. Geological Society ofAmerica, Memoir 169 , 1- 566. FORDYCE, R.E. 1989. Origins and evolution of Antarc tic marine mamm als. In: 1.A . Cra me (ed.) Origin s and evolutio n of the An tarctic biota. - Geological Society Specia l Publications, London 47, 269-281. NEW CRINOIDS FROM THE LA MESETA FORMATION 11 5

GAZDZICKI, A. and HARA , U. 1994 . Multilamellar bryozoan co lonies from the Eocene La Meseta Formation of Seymour Island, Antarctica: a preliminary account. - Studia Geo logi ca Poloni ca 104, 105-116. GAZDZI CKI, A. and T ATUR, A. 1994. New place names for Seymour Island (Antarctic Peninsula) introduced in 1994. Poli sh Polar Research 15, 83-85. G ISLEN , T. 1924 . Echinoderm studies.- Zoologiska Bidrag fran Uppsala 9, 1-330. HARA, U. 1995. Bry ozoans from the La Meseta Fo rmation (Eocene), Seymour Island, Antarctic Peninsula. - VlIlntema tional Symposium on Antarctic Ea rth Scienc es, 10-15 September 1995 . Siena (Italy). Abstracts, p. 181. HARWOO D, D .M . 1986. Diatom biostratigraphy and pa leoeco logy and a Ceno zoi c history ofAntarctic ice sheets. - Ph .D . dissertation , The Ohio State University, 592 pp . HARWOOD, D.M . 198 8. Upper Creatceous and lower Paleocene diatom and silicotlagellate biostratigraphy of Seymour Island, eastern Antarctic Peninsula. In: R.M . Feldmann and M.O . Woodburne (eds) Ge ology and Paleontology of Seymour Island, Antarctic Peninsula. - Geological Society ofAm erica, Memoir 169, 55-129. HENNIG , A. 1899. St udier ofver den ba ltiska Yn gre kritans bildningshistoria. - Geologiska Forenin gens i Stockholm Forhandlingar 21, 133-188. JOHN, 0 .0. 1938 . Crinoidea. - Discov ery Report s 18, 12 1- 222. KOH N, O. 1930. Das Danien del' au sseren Klippenzone bei Wien. - Geolo gische und Palaeontologische Abhandlungen 21, 495-525. LIIJDELL, W.D . 1975 . Rec ent crin oid biostratinomy. - Geologi cal Society ofAm erica, Ab stra cts with Pro grams 7, 1169. LLEWELL YN, G. and BAUM ILLER, T .K . 1993. Stem growth strategies for two Western Atl antic isocrinid species. - Geological Society of Am erica, Ab stra cts with Pro grams 25 (6) , A I04-A I05 . DE LORI OL, P. 1902.- Notes pour ser vir a l 'etude des Echinode rmes 2 (I), I- 52. MARENSSI, S.A., REGUERO, M.A ., SANTILLANA, S.M . and VIZCAI NO, S.F. 1994 . Eocene land mammals from Seymour Island, Antarctica: pale obiogeograp hic al implicat ion s. - Antarctic Science 6, 3- 15. MEYER , D.L. and MEY ER , K.B. 1986. Biostratin omy of Recent crinoids (Ec hin odermata) at Lizard Island, Great Barrier Reef, Au stralia. - Palaios 1, 294- 302. MEYER, D.L. and OJI, T. 1993 . Eocene crinoids from Seymour Island, Antarctic Peninsula: pa leobiogeographic and paleoeco logi c implicat ion s. - Journal of Paleont ology 67, 250- 257. MICIIELl N, H. 1853. Description d'un nouveau genre de la farni lle des Crinoides. - Revu e et Ma gazin zoolog ique. Ser. 11, Vol. 3, 93-94. MILLER, J.S . 1821. A natural history of the Crino ide a or lily-shaped animals, with obse rvations Oil the genera Asteria, Euryale , Comatula, and Marsupites. Bry an and Co.. Bristol. 150 pp . MORTENSEN, T. 19 17. Notocrinus virilis, n. g., n. sp. a new viviparous crinoid from the Ant arct ic Sea. - Videnskabelige Medd elelser fril Dansk Naturhistorik Forenin g i Kiibenhu ven 68 . 205-208 . MORTENSEN, T. 192 0. Th e Crinoid ea of the Swed ish Ant arcti c Exp edition. - Wissellschaftliche Ergebnisse der Schwedi s- chen Siidpolar-Expedition 1901- 1903. Band VI, Zoologie 11 . 1-23. NIELSEN, K.B . 19 13. Crinoiderne i Danmarks Kridtatlejringer. - Danmarks Geologiske Unde rsoegelse 2, 1-120. OJI, T. 1985. Early Cretaceous lso crinus from Northeast Jap an . - Pala eontology 28 . 629 -642. OJI, T. 1986 . Skeletal variation related to arm regenerati on in Metacrinus and Sara crinus, Recent stalked crino ids. - Lethaia 19. 355-360. OJI, T. and OKAMOTO. T. 1994 . Arm autotomy and arm bran ch ing patt ern as anti-preda tory adaptation s in stalked and sta lkless crinoid s. - Paleobiology 20, 27- 39. PORI;BSKI . S.J . 1995 . Facies arc hitecture in a tect onically-controlled inci sed-valley estu ary : La Meseta For mation (Eocene) of Seym our Island, Antarctic Peninsul a. - Studia Geo log ica Polonica 107. 7-97 . RADW ANSKA, U. 1996 . A new ec hino id from the Eoce ne La Meseta Formation of Seymour Island. Antarctic Peninsula. In: A. Gaidzic ki (ed.) Palaeont ological Results of the Poli sh Antarct ic Expediti on s. Part 11. - Palaeont olo gia Poloni ca 55. 117- 125. RASM USSEN. H.W . 1961 . A monograph on the C retaceous Crinoideu, - Kongelige Dan ske Videnskabern es Se lskab Bind, Biologiske Skrifter 12. 1-428. RASMUSSEN. H.W . 1978. Art iculata, 111 : R.e. Moore and e. Teichert (eds) Treatise 011 Invertebrat e Paleontology, Part T, Echin odermata 2, T81 3- T9 28. Geolo gical Societ y of A merica and University of Kan sas Press, Lawrence. RAsMussEN. H.W . 1979 . Crino ideos del C retac ico Superior y del Terciaro Inferi or de la Isla Vice comodoro Marambio (Seyrnour Island). Antartida . - Contribucio nes Cientificas del Institut o Anuirtico Argen tina 4, 79-97. RICHTER. R. 1930 . Warum heft en sich riffh ohl enbew ohn ende Crinoi de n tC vathidiunn han gend an ?- Paliiontologisch e Zeitschrift 12, 64- 65 . RINALDI . e.A., MASSABI E. A., MOREI.LI . 1.. ROSENM AN. H.L. and DE I. VAI.I.E. R. 1978. Ge ologfa de la Isla Vicecornod oro Marambio. - Contribuciones Cientificas del Instituto Antd rtico Argentine 21 7, 5-43. SADLER . P. 1988. Geometry and stra tifica tion of upp erm ost Cretaceous and Pa leogen e unit s of Seym our Island, northern Antarc tic Peninsula. 111 : R.M. Feldmann and M.O. Woodburne (eds) Geology and Paleont o!ogy of Seym our Island. Antarctic Peninsul a. - Geo logical Society ofAme rica, Memoir 169 , 303-320. SIEvERTS-DORECK , H. 1953. Cy rtocrinida . 111 : I. Piveateau (ed .) Traite de Paleontologie 3, 763 -765. S IMM S. M.J . 1988. Th e ph ylogen y of post-Paleozoic crino ids . 111: e.R.e. Paul an d A.B . Smith (eds) Echinoderm phvlogeny and evolutionary bio logy. 269 - 284. C lare ndo n Press. London. S IMM S. M.J. and SEVASTOPULO. G .D. 1993. Th e origin of artic ulate crinoid s. - Pala eontology 36 . 91-109. 116 TOMASZK. BAUMILLER and ANDRZE J GAZ DZICKI

SIMI'SON, G.G. 1971. Re view of foss il pen guins fro m Seymo ur Island .- Philosophi cal Transactions of the Roya l Society of London 8178, 375-387. STEENSTRUP, J.J .S. 1847. Uber Korallen in der Faxoer Kreide, Moltkia und Cyathidium. In: G .A. Mi ch aeli s and H.F. Scherk, 1847, Amtlicher Bericht iiber die 24. Ver sammlung Deutscher Naturforscher und Aertze in Kie l 1846, Ak ademisch e Buchhandlung , Kiel, 148-150. STILWELL, 1.0. and ZINSM EISTER, W.1 . 1992. Molluscan sys tematics and biostratigr aph y. Lower Tert iary La Me seta Forma tion , Seym our Island , Antarcti c Pen insula.- Antarctic Research Series SS, 1-202. STOI.A RSKI, 1. 1996. Pa leogen e corals from Sey mo ur Island, Ant arctic Peni nsul a. In: A. Gai dzicki (ed.) Palae ont ol ogical Results of the Poli sh Antarctic Expeditions. Part [I. - Palaeont olo gia Poloni ca SS, 51- 63. WOODBURJ'\ E, M.O. and Z INSI\I EISTER, W.1. 1982. Fossil land mammal from Antarc tica .- Science 218, 284-286. WOODBURNE, M.O. and ZINSMEISTER, W.l. 1984. Th e first land mammal from Antarctica and its biogeographic implicati on s. - Journal of Paleontology 58, 9 13- 948. WRENN, 1.H . and HART, G .F . 1988. Paleo gene din oflagellate cyst biostratigraphy of Seymo ur Island, Antarcti ca. In: R.M . Feld mann and M.O. Woodbume (eds) Geology and Paleontol ogy of Seymour Island, Antarctic Peninsul a. - Geolog ical Soc iety ofAmerica, Memoir 169, 32 1-4 47. ZINSME ISTER, W.1 . and CAMACHO, H.H . 1980. Late Eocene Struthiol ariidae (Mollusc a: Gastro poda) from Seyrn our Is land , Antarctic Peninsul a, and their sig nifica nce to the biogeography of early Terti ary shallow-wate r faunas of the Southem Hemisph ere . - Journ al of Paleontology 54, 1-14. ZINSMEISTER, W.1 . and C AMACHO, H.H. 1982. Late Eocene (to possibly earl iest Oli gocen e ) molluscan faun a of the La M eset a Formation of Se ym ou r Island , Antarctic Peninsul a. In: C. Craddock (ed.) Anta rctic Geosc ience , 299-304. Th e University of Wi sc on sin Pre ss, Madison, Wi scon sin . VON. ZITTEL, K.A. 1879. Handbuch der Paliionto logie, Band I, Paliiozoologie 1. 765 pp . Oldenbou rg, Miinchen and Leipzig. Palaeontologia Polonica, No. 55, 1996

T.K. BAUMILLER and A. GAZDZICKI: NEW CRINOIDS FROM THE EOCENE LA MESETA FORMATION OF SEYMOUR ISLAND , ANTARCTIC PENINSULA

PLATE 27

Notocrinus seymourensis sp. n. 110 Fig. I. Side view of crown with abraded centrodorsal, holotype ZPAL Ca.V/5, ZPAL 6, Telm2, x 3.0.

Cyathidium holopus STEENSTRUP, 1847 . . . 11 2 Fig. 2a. Side view of crown, ZPAL Ca.V/4, ZPAL I, Telml, x 1.8. Fig. 2b. Oral view of crown , ZPAL Ca.V14, ZPAL I, Telm I, x 1.7.

Eometacrinus australis gen. et sp. n. 107 Fig. 3a. Side view of crown, ZPAL Ca.V/2 , ZPAL I, Telm I, x 1.1. Fig. 3b. Side view of crown , ZPAL Ca.V12,ZPAL I, Telm I, x 1.2. Fig. 3c. Synarthry at IBn- 2, arrow points to synarthrial ridge of IBn, ZPAL Ca.V12, ZPAL I, Telm I, x 3.3. Fig.4a. Side view of crown, ZPAL Ca.V13, ZPAL I, Telm I, x 1.2. Fig.4b. Side view of crown, ZPAL Ca.V13, ZPAL I, Telm I, x 1.3. Fig. 4c. View of cup with basals and most proximal columnal, ZPAL Ca.V/3, ZPAL I, Telm I, x 2.8. Fig. Sa. Side view of crown, holotype ZPAL Ca.VII, ZPAL I, Telm I, x 1.1. Fig. 5b. Aboral view of abraded cup with basals missing , ZPAL Ca.VII, ZPAL 1, Telml, x 3.0. Fig. 6. Symplectial facet of an internodal columnal, ZPAL Ca.V/8, ZPAL I, Telm I, x 6.5. Fig. 7. Synostosial (cryptosymplectial) facet of an infranodal columnal, ZPAL Ca.V/9, ZPAL I, Telml, x 7. Fig. 8. Side view of pluricolumnal, ZPAL Ca.V17, ZPAL I, Telm I, x 2.0. Palaeonto logia Polonica. No. 55, 1996 Pt. 27

T.K. BAUMILLER and A. GAZDZICKI: NEW CR INOIDS FROM THE EOCENE LA MESETA FORMATION OF SEYMOUR ISLAND, ANTARCTIC PEN INSULA