https://doi.org/10.24199/j.mmv.1985.46.01 30 July 1985

TREMADOC TRILOB1TES FROM THE FLORENTINE VALLEY FORMATION, TIM SHEA AREA, TASMANIA

By P. A. Jell* and B. Staitj

Department of Invertebrate Fossils, Museum of Victoria, 285-321 Russell Street, Melbourne, Victoria 3000. 7001. 1 Departmenl of Geology, University of Tasmania, G.P.O. Box 252C, Mohan, fasmama Abstract

Trilobites from several horizons in the Florentine Valley Formation of the Tim Shea area *esi of Maydena, southwestern Tasmania are described and assigned late rremadoc to possibly early Arenig

I 1.5 La2 and possibly La3. raxa ages. I hen ayes approximate the Lancefieldian a /one of Psigraplus, described are Hystricurus penchiensis Lu, //. lewisi (Kobayashi), //. sp, cf. //. rpbustus Ross, el. A. Tanvbresma rasmaniensis gen. ei sp. now, Chosenia adamsensis sp. nov., Asaphellus sp. trinodosus Chang, Megistaspis (Ekeraspis) eudides (Walcott), Dlkelokephalina asiatica Kobayashi, isaphopsoides flarentinensii (Etheridge), Scotoharpes tauriei sp. nov., Pilekiidae gen. et sp. nov., Pilekia sp. nov., Protopliomerops hamaxhus sp. nov. and P. sp. el. P. punctatus Kobayashi.

Introduction linensis, the "Asaphellus" lewisi lo Asaphellus sp. cf. A. trinodosus Chang, and the Cybelop- Trilobites of the Florentine Valley Formation sis sp. to Protopliomerops haniaxitus sp. nov. in southwestern Tasmania received scant atten- Stait and Laurie (1980) provided identifica- tion until recently. Etheridge (1905) described tions for new irilobite faunas found in sequence Dikelocephalus florentinensis and Niobel sp. along the Gordon River Road on the western ind. from the Florentine River Valley near The side o\' The Needles. Our paper along with thai Gap {fide Corbelt & Banks, 1974). Kobayashi of Laurie (1980) provides the del ailed palaeon- (1936) reassigned the species florentinensis of tology for the discoveries of Stait and Laurie Etheridge to Asaphopsis Mansuy, 1920. (1980) and leads to several important revisions Kobayashi (1940) described lour species From a o\' ranges and nomenclature. Findings herein railway cutting at Junee east of ihc present are consistent with the assertions mady by Siail town of Maydena near the siding of Fitzgerald Fatirie (1980) aboul correlations and divi- species of and (fide Lewis,' 1940, p. 35); his two sions of the faunas but limitations are placed on Asaphopsis are considered synonyms of the ability to subdivide the faunas referred lo Etheridge's A, florentinensis, his two species of by Slait and Laurie (1980) as Assemblages 5, 6, Tasmanaspis are considered synonymous and and 7, until more seel ions are available to Tasmunaspis is considered a junior subjective confirm previous proposals. synonym of Hystricurus Raymond, 1913. He Illustrated material is housed in the Depart- assigned the fauna to the Lower Ordovician of Geology, University of Tasmania with the OT5 to ment and it may now be correlated (prefix UTGD), theTasmanian Museum (prefix OT7 time interval as discussed below. Z), and accessory collections are housed in Corbet! and Banks (1974) illustrated a those institutions and the palaeontological col- number of trilobites of the Florentine Valley lections of Ihe Museum of Victoria. Formal ion from The Ciap on the Florentine We are grateful to Penny Green University of Valley Road and from 5 Road to the southwest. Tasmania, and Annette Jell for curatorial Although they applied numerous specific names to Penny Clark for printing the in open assistance, and left many other specimens photographs from negatives made by the senior nomenclature we consider that they were author and to Heather Martin for typing the deceived, by the subtleties of the deformation on the manuscript. and failure' to employ latex casting collection; in trilobites, into oversplilting the specimens are localities and Irilobite fannus (Fig. I) our opinion all their hysiricurid all the The idealities from which trilobites are referable to H. lewisi (Kobayashi, 1940), described are numbered on the fossil locality asaphopsid specimens to Asaphopsoidesfloren-

l Memoirs ol the Museum Victoria, No. 46, 1MH5. P. A. JELL AND B. STALL

register of the Museum of Victoria (prefix Hyslricurus sp. cf, //. robust us Chosenia adumsensis NMVPL). Protopliomerops hamaxilus NMVPL1600, 1601, 1602 occur in the yellow Asaphellus sp. cf. A. Irinodosus siltstone (2nd lithology from base), dark grey A saphopsoides florentinensis calcareous siltstone, and yellow siltstones (near top) respectively, of the Pontoon Hill Siltstone Age Member (Stait & Laurie, 1980) of the Floren- Correlation of shelly Tremadoc faunas is tine Valley Formation on the Gordon River relatively tentative and considerable disagree- Road (19 km west of Maydena), where the ment still exists with relationships to a standard member extends on the State Grid scale still a long way off; for example Chugaeva Reference -Wedge 8112 from 535, 694 to 529, and Apollonov (1982, p. 82) place the shelly 685. fauna zones D, E, and F (of Ross (1951) and Hintze (1953)) in the Arenig whereas Miller el NMVPL1600 Hyslricurus penchiensts Lu, 1976 ul. in the same publication place Tanybregma tasmaniensis gen. el sp. nov. (1982, p. 177) Dikelokephalina asiatica Kobayashi, 1934 (he same zones in the Tremadoc, and evidence Pitekia nov. sp. for either does not seem strong. NMVPL1601 Hyslricurus lewisi (Kobayashi, 1940) (Assemblage 3 Asuphupsoides Jloreruinensis (Etheridge, The fauna from NMVPL1600 1905) of Stait and Laurie (1980) and OT3 of Banks Protopliomerops nov. hamaxilus sp. and Burrett (1980)) contains Psigraplus which Megtstaspis (Ekeraspis) euclides (Walcott, 1925) has been used to correlate with the La 1.5 zone Pilckiidac gen. el sp. nov. of Psigraplus of Cooper and Stewart (1979). NMVPL 1602 Hyslricurus lewisi The trilobites do not provide a distinctive cor- Asaphopsoides florentinensis Protopliomerops hamaxilus relation and although Dikelokephalina suggests Hyslricurus sp. cf. H. robuslus Ross. 1951 correlation with the Dikelokephalina Beds of Chosenia adumsensis sp. nov. Kazakhstan (Chugaeva & Apollonov, 1982), Asaphellus sp. cf. A. irinodosus Chang. 1949 the Carranya Beds of the Canning Basin, Scoloharpes lauriei sp. nov. Western Australia (Legg. 1978), and the Protopliomerops sp. cf, P. punclalus kobavashi, 1934 Clarkella zone of Korea (Kobayashi, 1934) such generic level correlation should be avoided if NMVPL182 and 183. Lower and upper beds possible and used only when a number of respectively at The on Australian Gap genera are involved. The medial Tremadoc age Newsprint Mills road into the Florentine Valley suggested by the graptolite is feasible but the from Maydena (see Corbett Banks, 1974, fig. & implied contemporaneity of the Digger Island 4; Stait & Laurie, 1980, fig. 1). Trilobite faunas Formation (Webby el ah, 1981) is doubtful in are identical at the two localities. light of comparison of the trilobite faunas (see

Hyslricurus lewisi discussion in Jell, 1985). Asaphopsoides florentinensis Succeeding faunas of the Florentine Valley Protopliomerops hamaxilus formation (Assemblages 4 to 7 of Stait and

Laurie 1 5 Road, this locality was detailed by Corbett ( 980) or OT4 to OT7 of Banks and Bur- reii and Banks (1974, fig. 4, locality 3) as coor- (1980)) contain and are distinguished by dinates 440, 400 E. 742, 500 N. on 5 Road in the Hyslricurus lewisi, Asaphopsoides florentinen- Florentine Valley. sis, and Protopliomerops hamaxilus; various other species occur with them at different Hyslricurus lewisi horizons. The fauna of OT5 may be Asaphopsoides florentinensis Protopliomerops hamaxilus distinguished from thai of OT4 by the ap- pearance of Chosenia, Asaphellus, and Hill 400 east of Adams Falls. Clear Road m Scotoharpes but following more detailed ex- junction with Adamsfield Adams Falls near amination of the faunas OT5 to OT7 may not Reference 8112: Track. State Grid -Wedge be subdivided on the basis of contained 423, 699. trilobites. Moreover, the utility of a zonal TREMADOC TRIl.OBITES IROM THE FLORENTINE VALLEY

Tasmania .showing fossil localities. Figure 1. Sketch map of Maydena-1 im Shea area southwestern induced scheme based on faunas of the Florentine beds. The distortion at NMVPL1600 some hystricurid heads to Valley Formation will depend on ils applicabili- I he tubercles on much more prominent and asym- ty to other sections which are not yet known. become whereas in others it seems Indeed difficulties of correlating the Digger metrical (PI. 1. fig- 3) completely subdued the luberculation Island Formation fauna (Jell, 1985) with this io have section suggest that use of the trilobite faunas (PI. I, fig. 1). to place Although il may appear nonsense to establish a biostratigraphy may be premature (PI. figs 7 and 8) in the same and detailed taxonomy of all known sections is iwo pygidia 5, the marked dimensional differences necessary before a workable scheme can be species, be explained as compression from established. may best directions. The trilobites of these assemblages are not in- different interesting to note that at NMVPL1600 consistent with the late Tremadoc to early Ii is is marked but there has been no frac- Arenig age previously suggested (Laurie, 1980; distortion large flat 1980). ture of the exoskeletons (even of the Stait & Laurie, 1980; Banks & Burrelt, Dikelokephalina asiatka) as there is at most in the large flat Preservation other localities particularly The state ot The fossils are preserved as moulds in fine- Asaphopsoides ftorentinensis. fossils removes any grained decalcified shale to fine sandstone of a preservation of the considerable the use of any biometrics so no variety of colours. There has been confidence in but more or reconstructions are included distortion of the fossils at all localities measurements and Adams descriptions; sizes of individuals are in- so at some (e.g., NMVPL1600 in the and 5 in plate explanations and most Falls) than at others (e.g., NMVPL182 dicated in the features are not measurements. Road). The fossils all appear to have lam distinguishing and distortion is generally in bedding planes Systematic palaeontology development of slatey two dimensions with Moore & nodules at Terminology follows Harrington, cleavage. Those fossils in decalcified as far as possible; occipital NMVPL1601 and 1602 are much less deformed SlLibbleficld (1959) all dimensions in the shaly ring is included in I he glabella; than others at the same localities in P, A. Ill I AND H. SIAI I

the sagitlal Or exsagiital directions arc discussed with weak apodemal depressions in furrow

in terms Of length and all dimensions in the laterally, wilh ring lapering laterally behind transverse direction are discussed in terms of apodemal pits and passing across axial furrow width (Tor example the anterior craniclial as very low ridge into posteroproximal corner

border whose sagitlal dimension is often impor- of fixed check, without median node or

tant in specific description is described in terms posterior spines on ring; axial furrow wilh of long 01 short in our terminology). elongate fossulae at anterolateral corners of glabella, shallowing over axis in front of Class Trilobita glabella; preglabellar held weakly convex; Family HYSTRICURIDAE Hupe, 1953 anterior border furrow shallow, long, wilh gently sloping walls front and back, almost Hystricuriis Raymond, 1913 transverse, without ornament; anterior border Type species (by original designation): short, weakly convex, without ornament, taper- Hal fi yarns conicus Billings, 1859. ing laterally from near exsagiital line through

sides of glabella as facial suture cuts across it; Ilyslricurus pencil iensis Lu, 1976 interocular cheek wide, rising up from axial

Plate 1, figures 1-15 furrow but flat distally; palpebral furrow, run- anterior posterior Material: Ilolotype Nanking Institute of ning around both and of Geology and Paleontology No. 23885 (Lu, palpebral lobe lo cross facial suture and con- tinue librigena beneath eye socle; palpebral 1976, pi. 7, fig. 10), paratypes NIGP23886 to on 23888 all from the Cal/ograptus ? taitze/ioensis lobe arcuate, almost semicircular, relatively long at 0.4 cranidial /one of the Yehli Formation in Liaoning Pro- of length, sloping up abaxially, wider posterior to the vince ot northeastern China. Some fifty becoming midlength, disassociated cranidia, pygidia, librigenae and without ornament; facial suture diverging for- thoracic segments as well as two articulated ward from palpebral lobe in curve to widest poinl just behind border specimens are available from NMVPLI600 in- furrow, then curving cluding the figured specimens UTGD1 22500 to Strongly across border to anterior margin, run- 122518. ning transversely from posterior of palpebral lobe lo well beyond lateral extremity of Diagnosis: Member of Hystricnrus with sub- palpebral lobe before turning sharply back for quadrale glabella; relatively long preglabellar very short distance lo posterior margin; held (0.3 of cranidial length); palpebral lobe posterior cephalic limb short and wide, without long (0.4 of cranidial length), situated pos- ornament, occupied mostly by well impressed teriorly, becoming wider posteriorly, defined by transverse posterior border furrow of uniform distinct palpebral furrow parallel to margin of length, with shorl convex posterior border the narrow lobe; librigena With marginal terrace behind. Librigena longer than wide, gently con- lines, with strong genal spine bearing extension vex; wilh genal spine of more than half of border furrow down its midline. Pygidium cranidial length, visual surface almost three with axis of four rings and short, medially times as long as wide (or rather high), standing divided terminus reaching border furrow; almost vertically, only weakly convex pleural and interpleural furrows extending lo transversely, apparently holochroal although border; binder narrow in dorsal view, wilh high lenses not clearly distinct; eye socle low, dis- marginal band bearing strong parallel lerraee linet, rim-like beneath visual surface, lines; doublure narrow. defined below by broad shallow furrow continuous Description: Craiiidium wilh coarse tubercular from palpebral furrow; genal field weakly con- ornament glabella on and cheeks. Glabella vex, gently dovvnsloping abaxially from sharp without furrows, with straight parallel sides change of slope at furrow beneath eye, with posteriorly, tapering gently over anterior hall, coarse tubercular ornament over adaxial half wilh truncated anterior rounded on corners; oc- (tubercles of two sizes) and extremely fine low cipital furrow and ring of about equal length, radial caecal network extending from eye socle TREMADOC fRILOBlTES FROM 1 HI I 1 OKI N UNI \ At 1 I V

to border; border furrow well impressed, rising percept ible posteromedian indentation; steeply up onto border bui smooth? up cheek, doublure narrow, extending in and I lien up lo continuing down genal spine as merging lateral approach the dorsal exoskelcton benealh I he and posterior parts, not tunning around genal border furrow and enclose cylindrical Space angle; posterior border furrow deeper and within i lie border. just in lateral border furrow deepening from Remarks: flu- rasmanian material is assigned from of genal angle back; border convex lo this Chinese species on the comparison with throughout becoming much narrower and more lu's (1976, pi. 7, tig. 11) Battened specimen genal convex behind a point just in front of the where the glabellar shape is identical with that to angle, with continuous terrace lines parallel of the Tasmanian specimens all of which are out at the margin on anterior part but fading flattened. Preglabellar, palpebral and occipital the same point the convexity of the border structures ate identical and there can be little changes; genal spine not continuing curve of doubt about the specific identity. Although the very slightly abaxial- cheek margin but running genal spine looks shorter on I u's (1976, pi. 7, sides of deep ly, with high convex rims on both fig. 12) specimen it seems likely that the ventral as furrow running down its centre; doubluie mould of the spine is incomplete and may go in- enclose wide as border, convex ventralU to to the matrix on the counterpart. I'hc internal not cylindrical space in border. Hypostome mould of the pygidium figured by 1 U does unknown. allow adequate comparison but observable Thorax of at least nine segments (no com- features are identical, when compared with rings of uniform size (e.g., PI, plete thorax is known); axial 1 asmaiuan pygidia of comparable Asian length, each with median node; pleural furrows 1, fig, 15). In (1976) compared the well impressed, beginning at the anterior species //. megalops Kobayashi, 1934 ami //. margin in the axial furrow, occupying most of %ranosus Endo, 1935 both of which are the length of the segment, fading out down free distinguished by their narrower more rounded pleura against back of wide short inclined facet; glabellar shape and shorter preglabellar field. anterior and posterior pleural bands each with H. flectimembrus Ross, 1951 has precisely the single row of tubercles; pleural tips with genal spine structure of the rasmanian posterolateral points. specimens. Hystricurus wilsoni Gobbett, I960 ornament as well Pygidium transverse, with convex axis stand- is similar lo //. penchiensis in of the cranidium and ing above less convex pleural areas; axis tapering as in general arrangement species I he Spitsbergen slightly posteriorly; axial rings with prominent pygidium. However, l may be high tubercle on anterior one and low less- and //. flectimembrus from Hah prominent node on second, progressively disiingushed from //. penchiensis by the spines shorter posteriorly, of uniform length with on ihc teai of the cranidium and on I he thoracic shorl wide pseudoarticulating halfrings on first segments. and second; terminus triangular, reaching Hystricurus lewis! (Kobayashi, 1940) down to posterior border furrow, divided sngit- furrow tally into left and right lobes by distinct Plate 2. figures 1-15; plate .1, figures 9, 1(1, 13 deepest anteriorly; pleural areas with well im- I94d Tasmaneapls lewisi Kobayashi, p. 65, pi. !!, figs i, pressed pleural and interpleural furrows; with 4. rib bcai ing pi. II, anterior and posterior bands of each 194(1 Tasmanaspis longus Kobayashi, p. 66, tig. 5. Hanks, .ill fur- Hystricurus paragenatatus Koss; Corbeti & a transverse row of small tubercles, with 1974 pi. figs 16, 2o. pi. 2, tig. ii. directed more posteriorly i, rows becoming 1974 Hystricurus sp. Corbeti .x Hanks, pi. i, figs 21, tire almost ex- towards the posterior where they 2S -27, pi, 2, li>'.. 12. dorsal 1974 hyslricurid librigenae Corbeit & Banks, pi. I, fig. 19. sagittal; border extremely narrow in 1980 Hystricurus lewisi (Kobayashi); Man & I aurie, Rg. of uniform width, defined by view, rim-like, 3, Appendix I • shallow posteriorly tapering bolder furrow, Holotype: Z151 from 'railway culling 3.2 km with high marginal band bearing continuous (i.e. just east of barely west of .ituicc Railway Station' parallel terrace lines, with broad often P. A. JELL AND B. STAIT

present day town of Maydena) in the Florentine transverse border furrow; anterior border of Valley Formation. uniform length, short, (may appear to be variable in length to preservation Other material: Some 80 to 100 disarticulated due — steeply cranidia, libragenae, and pygidia from upsloping forward was probably original at- NMVPL182, NMVPL160I, NMVPF1602 and titude, appearing shorter than on flattened ones), with line 5 Road including Z150 (hololype of Tas- marginal terrace lines; eye lines barely evident on some specimens; manaspis longus), Z995, material figured by palpebral lobe relatively short, arcuate, Corbel! and Banks (1974), and material ligured bulging laterally, to herein are present in the collections of the flat slightly downsloping abaxially, situated Tasmanian Museum, Department of Geology, adjacent to midlength of glabella; palpebral University of Tasmania and the Museum of furrow poorly impressed medially but distinct Victoria. at ends of palpebral lobe, not parallel to lobe margin but rather culling across base of lobe, Diagnosis: Glabella tapering forward, anterior- continuous around ends of lobe onto free cheek ly rounded, extremely faint lp furrow; beneath eye surface; posterior cephalic limb preglabellar field short, becoming longer with wide (glabella only 0.35 of basal cranidial growth; palpebral lobes short, wide, highly ar- Width), subtriangular in shape, with well im- cuate; anterior sections of facial suture diverg- pressed posterior border furrow becoming ing to just behind border furrow then cutting longer laterally; posterior border becoming across border diagonally over a short transverse elongate abaxially, short and convex adaxially; distance; librigena with convex border hearing facial suture running in fairly straight diagonal continuous marginal terrace lines running down line from posterior of palpebral lobe to proximal part of genal spine. Pygidium posterior border, then turning sharply back to transverse; axis of four rings and short medially margin. divided terminus without distinct posterior Librigena downsloping abaxially, visual sur- boundary; axial furrow extending almost to face vertical, nearly four times as long posterior border furrow; pleural areas with as high, gently convex in both anterior and dorsal sharp geniculation forming ridge parallel to profiles; eye socle low, merely a rim margin some distance abaxial to border furrow- beneaih visual surface; furrow beneaih border and doublure quite narrow. Pygidium eye socle very shallow but distinct without ornament, con- smooth but cephalon with fine (uberculate or- tinuous wilh palpebral furrow of nament becoming less obvious with growth. fixed cheek; genal field with ornament on adaxial part Description: Small and convex for the genus decreasing towards border furrow, genlly con- with variable subdued ornament of pustules on vex; border furrow well impressed bul shallow- all parts of exoskeleton except in furrows and ing distinctly for short section just in front of on the border; cranidium with broadly convex genal angle, continuing down genal spine where glabella standing above cheeks; glabella with posterior and lateral border furrows merge inio extremely vague suggestions of wide gently- one furrow for short distance; doublure as wide oblique lp furrows (e.g., pi. 2, lig. 15, centre); as border extending quite a distance forward axial furrow well impressed, sharper and deeper beyond genal field, terminal ing forward on an in front of glabella (probably indicating oblique rostral suture. fossulae) and shallowing adjacent to glabellar Pygidium transverse, convex, apparently lobe lp; occipital ring short, flat in lateral without ornament; axis of four rings and short profile, tapering laterally; occipital furrow widely divided terminus, convex, standing sharp and deep, with apodemal pits laterally above pleural areas; articulating half ring short but then shallowing to almost nothing adjacent standing up high medially; axial rings each of to axial furrow; preglabellar field always short, uniform length, becoming shorter towards or variable length depending on stage of growth posterior until fourth ring is extremely short but mostly on post-depositional distortion, rim; terminus represented by two lobes downsloping forward into well impressed separated by wide medial depression, not clear- TREMADOC fRILOBITES FROM THE FLORENTINE VALLEY

ly distinguished posteriorly; axial furrow not lewisi are the result of lateral compression as impressed but expressed as change of slope opposed to sagittal compression in the type of from axis onto flat proximal part of pleural H. lewisi. The eye ridge and length of occipital area, continuing posteriorly down steep slope ring are not distinctive and the relative length of of pygidtum to finish near posterior border fur- preglabellar area and position of palpebral lobe row (extension down posterior slope may be are not quoted accurately because Kobayashi's

fourth interpleural furrow simply continuing illustration of the type of H. lewisi is retouched line of axial furrow but this cannot be deter- in the left posterior region; the posterior

mined without knowing termination of axis cephalic limb is not preserved and the posterior which in H. penchiensis becomes much lower as margin of the occipital ring is not evident

it extends posteriorly towards the posterior either. Kobayashi's specimens from Junee have border furrow); pleural area clearly divided by been flattened during diagencsis as well as sharp geniculation forming prominent ridge distorted and this flattening has produced the parallel to margin a considerable distance inside apparent elongation of the preglabellar area. the border furrow; adaxial part of pleural area However the distance from the depth of the

Hat, crossed by four long gently sided pleural border furrow to the tip of the border is ap- furrows and three (or four, depending on inter- proximately the same in most of the larger pretation of posterior) short sharp interpleural specimens from the other localities listed above.

furrows; pleural furious cutting diagonally Perhaps most important of all is structure of back across segment from axial furrow, the palpebral lobe which in mature specimens finishing against ridge of geniculation; in- (e.g. PI. 2, fig. 13) has the palpebral furrow well terpleural furrows continuing through gaps in away from the margin at the midlcngth of the geniculation ridge, running down steep outer highly arcuate lobe just as it is in the holotype. slope almost to border furrow; outei part of In juvenile specimens this lobe is much nar- pleural area sloping steeply down to border, rower. As this and all other non-dimensional smooth excepl for interpleural furrows; border features match, the identity of these recent col- extremely narrow, tapering forward) merely a lections as H. lewisi is almost certain. flange at base of steeply sloping pleural area, The wide flat palpebral lobes approach defined by poorly impressed border furrow at Parahystricurus Ross, 1951 and although the change of slope, with fine parallel continuous forwafd position of the lobes is distinctive of terrace lines along margin; doublure narrow, that genus the closest species to //. lewisi may convex, leaving cylindrical space in border; ar- well be P. pustuloses Ross, 1951 and related ticulating facet small sloping steeply abaxially; forms. pygidium without ornament. The pygidium resembles closely that figured Remarks: Kobayashi (1940) nominated this by Ross (1951, pi. 19, figs 6, 11, 15) from his with the ridge on the pleural species as the type For his genus Tasmanaspls /one E marked area particularly distinctive. Ross's suggestion and the holotype is an internal mould, refigured thai ii probably belongs to Parahyslrieurus herein (PI. 2, fig. 2), of a medium sized cranidium. The features quoted by Kobayashi carinatus Ross, 1951 further suggests alliance Parahyslrieurus although it is as distinguishing Tasmuuuspis are not of o\ II. lewisi with below that Ross's pygidium may generic significance in the modern understan- suggested Hystricurus robustus which occurs at ding Of Hystricurus and the "concavo-convex belong to the same locality. curvature of the frontal limb and rim" is con- Hystricurus megalops Kobayashi, 1934 from sidered to appear distinctive only by virtue of Korea and //. granosa Endo, 1935 from I.iaon- the preservation at the type locality. ing, China resemble each other as well as H. TasmanaspU is undoubtedly a junior synonym in glabellar shape, ornaent and most pro- of Hystricurus. lewisi so that the three Angle of the facial suture and elongate portions of the cranidium may cranidium, quoted by Kobayashi (1940) as prove ultimately to be synonymous but we distinguishing Tasmanaspis longus from T. prefer to retain the Tasmanian name until a P. A. JELL AND B. STAIT

fuller understanding including knowledge of course pustules on the external surface of H. pygidia is available for each of the Asian robustus. species. Tany bregma gen. nov. Hystricurus sp. cf. H. robustus Ross, 1951 Etymology: From the Greek tany meaning long

Plate 3, figures 8, 11, 12; plate 4, figures 1-7 and bregma meaning front of the head; the reference is to the considerable preglabellar Material: Some 20 to 30 cranidia librigenae, and pygidia from NMVPL1602 and from the length. Adam's Falls locality. Type species: Tanybregma tasmaniensis sp. nov. Description: Ross (1951, p. 51, 52) gave a detailed description of this species so only Diagnosis: Cranidium subquadrate, of low con- those features that add to or are at variance vexity, with tuberculate ornament of two with his description are mentioned here. Ross's different sizes on glabella and interocular specimens are smaller than these Tasmanian in- cheeks; glabella tapering forward, truncated dividuals so some of the features that do not anteriorly, with long lp furrow at high angle to match exactly are probably due to comparison transverse line; preglabeller length more than of different growth stages of the species. In the 0.35 total cranidial length, with well developed

Tasmanian material the palpebral lobe is even caecal network, gently downsloping forward; wider and just a little shorter; the facial suture anterior border short, upturned; palpebral lobe runs directly forward from the anterior of the long, situated posteriorly, arcuate but narrow, palpebral lobe (PI. 4, figs 1, 3) (distortion of in- limited by well impressed palpebral furrow; dividuals in PI. 4, figs 4, 6 erroneously suggests facial suture diverging forward from palpebral divergence) and runs diagonally back to the lobe to widest point near anterior of border fur- margin from the rear of the palpebral lobe; on row, transverse behind palpebral lobe. Lib- the librigena the genal spine is deflected a little rigena with extremely wide doublure reaching more noticeably laterally and does not exhibit well forward of genal field and terminating the same adaxial curve in its posterior part. there in a rounded rostral suture. The pygidium figured by Ross (1951, pi. 19, Remarks: This genus is based on cranidia and figs 6, 11, 15) from the same locality as the librigenae only but it is possible that the cranidia named H. robustus are identical with pygidium is so similar to that of the co- the Tasmanian pygidia and may belong to this occurring H. penchiensis that it is not possible species rather than Parahystricurus carinatus as to separate them in the deformed state in which suggested by Ross in the explanation of his they are found. Cranidial features are reminis- plate 19. Moreover the thorax assigned to H. cent of Hystricurus but the longer preglabellar robustus (Ross, 1951, pi. 14, fig. 27) is identical field, lp furrow, row of denticles on the adaxial with the Tasmanian specimen (PI. 3, fig. 12) in side of the genal spine and in particular the all observable features. wide doublure and curved rostral suture Remarks: This species is difficult to distinguish distinguished Tanybregma. It has some from H. lewisi with which it stands out from similarity to a number of genera but none has the rest of the genus by virtue of its palpebral the combination of Tanybregma; Nyaya structure. However the two may be separated Rozova, 1968 is shorter in front of the glabella,

by H. robustus having coarser tuberculate or- has longer less arcuate palpebral lobes and is nament overall, much shorter preglabellar field, smooth but it does have a pygidium that could exsagittal to converging course of facial sutures easly be confused with that of H. penchiensis. forward of palpebral lobes, and occasional Some species of Hystricurus, namely H. spp. A tubercles on the pygidial pleural ribs. The and E of Ross (1951, pi. 9, figs 31, 34, 37 and resemblance of the pygidia of the two species is pi. 15, figs 10, 11, 13, 14) show a tendency remarkable as the only distinguishing feature is towards preglabellar elongation so it is not the fine pustules on internal moulds and rare unreasonable to suggest that Tanybregma may TREMADOC TRILOBITES FROM THE FLORENTINE VALLEY

have arisen out of a form like //. penchiensis two parallel trunks, separated from palpebral with the features cited above sufficient to war- lobe by sharp extension of palpebral furrow; rant generic separation. Hyperbolochilus Ross, palpebral lobe with short very narrow exsagiltal 1951 (type species H. marginauctum Ross, anterior section, remainder arcuate, almost 1951) is superficially similar but its short semicircular, of uniform width, narrow, defin- palpebral lobes, glabellar shape and course of ed by well impressed palpebral furrow, more its rostral suture are distinctive at the generic than half as long as glabella, situated posterior- level. Hystricurus (Guizhouhystricunts) Yin in ly; palpebral furrow cutting off eye ridge from Yin & Li, 1978 (type species H. (G.) yinjiangen- beneath eye socle on librigena; facial suture sis Yin & Li, 1978) has the long preglabellar diverging forward from anterior of palpebral fair- field of Tanybregma but is clearly distinguished lobe to be widest at border furrow, cutting then run- by its short convex anterior border and ly directly across anterior border but palpebral structure indicating placement in a ning along close to anterior margin for some separate hystricurid lineage. distance before reaching margin, almost transverse behind palpebral lobe, extending Tanybregma tasmaniensis sp. nov. well beyond abaxial extremity of palpebral lobe Plate 3, figures 1-7; plate 8, figure 7 then curving posteriorly to reach margin at high short, wide, with Etymology: This species name refers to its angle; posterior cephalic limb border furrow neat- discovery in Tasmania. well impressed posterior anterior, with highly convex abaxially- Material: Holotype UTGD95983, paratypes elongating posterior border occupying most of UTGD96674, 96676, 122528 to 122531 and its length. 122554 plus some 10 to 15 cranidia and Librigena smooth, with long genal spine; librigenae in the collection of the Museum of visual surface at high angle to genal field, of Victoria, all from NMVPL1600. uniform width, with well rounded ends, ap- genus. Diagnosis: As for parently holochroal; eye socle low, simply a rim Description: Cephalon semicircular, of low appearing like a piece of wire lain beneath the to convexity; cranidium a little longer than wide visual surface; genal field sloping gently oul but generally subquadrate; glabella with gently border furrow, longer than wide; border fur- of curved sides converging forward, truncated row wide and shallow as on anterior length anteriorly by transverse preglabellar furrow cranidium, continuing posteriorly down and and rounded anterolateral corners, with well of genal spine after merging of posterior angle; impressed lp furrow extending from close to lateral border furrows just behind genal upturned, with axial furrow at level of midlength of palpebral bordei narrow, convex, sharply transverse genal spine quite lobe in a straight line at high angle to subdued terrace lines laterally; sagittal bearing set of or to finish close to occipital furrow near long, with posterior border 9 with denticles as il runs down line; occipital furrow deep, steep sided, 10 or more dislinci pits spine; doublure wide, with fiat bottom, with wide deeper apodemal adaxial side of genal continuous anastomos- laterally separated from axial furrow by narrow well developed parallel into angular ridge very shallow part of furrow; occipital ring of ing terrace lines, developing beneath uniform length, without median node, convex running down centre of genal spine impressed extending some distance for- in lateral profile; axial furrow well border furrow, where it terminates but shallowing anleromedially and posteriorly; ward of the genal field convex rostral suture. preglabellar field long, gently downsloping, against an adaxially with typical caecal network, approximately border fur- equal in length to the border plus Family LEIOSTEGIIDAE Bradley, 1925 furrow long, shallow; anterior row; border Chosenia Kobayashi, 1934 border concave, flattening out near border, up- eye Type species (by original designation): turned, of uniform length throughout; consisting of Chosenia lulicephala Kobayashi, 1934 from the ridge narrow and relatively long, P. A. JELL AND B. SI All

Early Ordovician Clarkella Zone at Saisho-ri, ulnchi Berg & Ross, 1959, pi. 21, figs 1, 6).

South Korea. There is undoubtedly a close relationship be- Diagnosis: Leiostegiid with weakly impressed tween the two genera but features of the glabellar furrows; glabella truncated anteriorly; pygidium other than the marginal spines (see critical in this anterior border shorter and more convex in discussion of species below) are front of glabella, longer and flatter laterally; group of trilobites. Taking the pygidia into con- strong caecal trunk issuing from anterolateral sideration the well impressed pleural furrows corher of glabella, crossing axial furrow but nol are probably most distinctive; also important is continuing; eye ridges beginning much further the course of the border furrow anterolateral^'. back in axial furrow, oblique (c. 45°) to ex- These features along with the larger anterior sagittal line; palpebral lobes short, situated lixigenal area on the cranidium, laterally longer posteriorly. Pygidium transverse; anterior anterior cranidial border and glabellar shape border furrow curving back strongly behind ar- distinguish Chosenia from Evansaspis ticulating facet and running to margin in front Kobayashi, 1955 whose type species is E. of marginal spine; with relatively wide border; glabrum Kobayashi, 1955 from the Lower Or- pair of long marginal' spines issuing from first, dovician McKay Group in British Columbia. second or third pygidial segment; pleural fur- Evansaspis resembles Chosenia adamsensis rows well impressed; interpleural furrows evi- specifically only in the position of its pygidial dent. marginal spines as discussed below. A case for considering Chosenia a subgenenus of Other species: Apart from the type and C. Leiostegium could be made on (he basis of the adamsensis described here, only C. divergent similarities between C. udamsensis and Evan- Lu, 1975 from the Acanthograplus-Tungtzuella saspis but we consider that the pygidial struc- Zone (late Tremadoc) of the Fenhsiang Forma- ture of Chosenia indicates a separate lineage tion at Yanshuiping, Changyang, western worthy of generic separation but included in the

Hupeh Province, China is assigned to this same family. How each of these groups is

genus. related to Leiostegium and its origins is not yet

apparent but if its origin is from the Remarks: The type species was poorly il- Kaolishaniidae as seems most likely then one of lustrated and does not provide sufficient mor- these lineages may have produced Leiostegium phology upon which to interpret a separate by loss, possibly into the thorax, of the genus. The fragmentary holotype cranidium macropleural segment. The possibility should (Kobayashi, 1934, pi. 8, fig. 8) is particularly be investigated thai the Chosenia line may have unsatisfactory. However, one paratype emerged from the Mansuyiinae with its or- pygidium (Kobayashi, 1934, pi. 8, fig. 11) namented pygidial spines, well impressed shows sufficient morphology to be confident pleural furrows, subtle pygidial border, that it is congeneric, if not conspecific, with posterior eyes and large faint glabellar furrows Chosenia divergens. Pygidial characters of the and thai Evansaspis may have emerged from genus may be discerned from Lu's (1975, pi. 2, the Kaolishaniidae with more prominent figs 28-31; pi. 3, figs 1, 2) well illustrated pygidial borders, less distinct pleural furrows, pygidia. However, the only cranidium figured and better impressed lateral glabellar furrows. by him is also fragmentary and reveals only a If this proves to be so then the Leiostegiidae few more features than the type species. would be polyphyletic. Assignment of Chosenia adamsensis sp. nov. Leiostegium {Leiostegium) floodi Shergold, is discussed under that species below but its 1975 from the early Tremadoc Oneotodus inclusion allows a somewhat more complete hicuspatus with Drepanodus simplex zone of understanding of the morphology and the lower Ninmaroo Formation at Black Moun- systematic position of Chosenia. The cranidium tain, western Queensland may well be a species is almost identical with that found in some of Chosenia also but it is not possible to species of Leiostegium Raymond, 1913 (e.g. L. distinguish the genera on cranidia alone. I Rt MADOC TKII OBITES I ROM I HH F I OREN1 INE VALLEY II

Chosenia adamsensis sp. nov. fading into the cheek; crossed by low ridge from anteriorly-curving occipital ring into Plate 4, figures 8-11; plate 5, figures 1-10 posterolateral corners of cheeks; preglabellar Etymology; Named for Adam's Falls near the held absent; anterior border furrow deep and species. type locality of this long in from of glabella, shallower and shorter vertical wall up Material: Holotype UTGD122535, and in from of cheeks, with almost and sleep but gentler slope paraiypes UTGD95175, 95927, 95942, 95945, onto border anterior border highly convex, flat- 96023, 96025, 96027, 96029, 96602, 96611, posteriorly; tened and sloping forward in lateral profile, 96637, 96642, 96646. longer laterally (before tapering along facial Diagnosis: Member of Chosenia with well im- suture), excavated posteromedial!)! by the pressed palpebral furrows, lubereulate orna- border furrow thrust forward in front of the ment, pair of long curving pygidial marginal elongate glabella, with continuous terrace lines spines from second or third segment of near and parallel lo the margin; eye ridge pro- pygidium. minent, composed of two parallel caeca, at ap- 45° not Description: Moderately large convex species proximately to transverse, meeting but (nearly 0.3 (cephala up to 2.5 cm long); surface ornament crossing axial furrow well back from glabellar anterior; palpebral of fine sparsely scattered tubercles over whole of glabellar length) exoskeleton. Cranidium subquadrate, with gla- lobe strongly arcuate, short, situated opposite glabella, strongly elevated bella lower than cheeks; glabella with straight posterior third of and then Battened on lop medially; palpebral sides, tapering slightly forward, with anterior furrow well impressed shallowing over mid- truncated to broadly curved, highly convex in lobe, running across eye anterior protile; lateral glabellar furrows in 4 length, parallel lo palpebral lobe, turning pairs not evident on all specimens, shallow, in- ridge at junction with

posterior of I he lobe; facial distinct; lp furrow directed obliquely back down around to sutures diverging slightly forward from anterior from i he axial furrow but then curving be to border furrow, cutting transverse and shallower bul continuous sagit- of palpebral lobes diagonally al low angle to transverse across lally in smaller specimens, discontinuous in border, highly arcuate around larger specimens; lp and 2p furrows joining in anterior palpebral lobe then dropping down almost ver- axial furrow in smaller individuals, appearing tically and slightly posteriorly lo the posterior as a Y-shaped furrow in larger individuals; 2p, margin in the same exsagittal line as the outer- 3p and 4p approximately parallel to lp but not mosi on the palpebral lobe; posterior curved adaxially and not conlinuous over axis, point furrow well impressed, of uniform becoming progressively shallower and Shorter border length throughout, transverse; posterior border forward, 4p in front of eye ridge, and not convex, of uniform length throughout, reaching axial furrow, 3p meeting axial furrow short, strongly downlurned as part of cephalic just behind eye ridge; tuberculale ornament on posterolateral limb beyond articulating point lateral glabellar lobes bul not furrows; occipital behind posterior of palpebral lobe. furrow well impressed, long, with steeper wall directly Librigena with broad, gently convex genal in from than behind, transverse medially but field; eye socle high, vertical, marked off by a with narrow posteriorly sloping lateral sections compos- accommodating apodemes; occipital ring of wide poorly-impressed furrow; border parts separated by a shallow uniform length, flattened on top in lateral ed of two distinct furrow, rather flat; outer part narrow, with profile, with only extremely vague antero- comarginal terrace lines continuing median node; axial furrow deep and wide, of continuous suture onto cranidium, terrace uniform width, with a pair of strong foSSUlae al across facial lines running over margin at end of outer part anterior border furrow and another pair of pro- of border near midlength of eye, tapering to minent pits just behind the strong ridge before level of posterior border fur- (caecum) extending out of the anterolateral cor- nothing the axial furrow and row; inner part of border broader than outer ner of l he glabella across 12 P. A. IIII AND H. MAI I

part, beginning anteriorly with a smooth area margin in front of spine; interpleural furrows just behind the facial suture and continuing evident on first three pleural ribs; border fur- posteriorly into a long strong genal spine, with row shallow, indistinct, beginning behind less-regular sometimes anastamosing longitu- marginal spines; border relatively narrow, of dinal terrace lines that continue down the genal uniform width, with some terrace lines near the spine; border wide in area of overlap of two margin, convex near the border furrow then parts but rather narrow anteriorly and with flatter and down sloping distally; pair of strong reduction in width posteriorly at the marginal spines issuing from second or in some spine base; posterior border short and highly specimens third segment of pygidium, long, convex; border furrow short and deep curving adaxially, with fine longitudinal discon- posteriorly, with small re-entrant in base of tinuous and rarely anastamosing terrace lines; genal spine (elongate into a furrow down the doublure convex ventrally, with well developed spine in one specimen) where posterior border continuous and anastamosing terrace lines, furrow comes to genal spine, shallow laterally, widest anteriorly, narrowest sagittally, swing- continuing in curve onto cranidium; rostral ing around anterolateral corner to finish at suture running adaxially towards posterior. lateral articulating process. Thorax of 10 segments, of uniform widih; axis with deep axial furrow having narrow Remarks: This species is assigned to Chosenia posteriorly-sloping parts and apodemes as in on the basis of the cranidial similarities with occipital furrow; articulating half-ring short, Lu's (1975, pi. 2, fig. 27) C. divergens and on smooth, almost as high as ring; ring of uniform pygidial features behind the segment carrying length running back from axial furrow for the macropleural marginal spine. We suggest short distance then transverse medially; axial that the more posterior position of the spine in furrow weakly impressed; pleurae Hat to ar- C. adatnsensis is due to the fact that one or two ticulating line then gently down turned beyond; thoracic segments remained ankylosed in the well impressed pleural furrows occupying most pygidum (i.e. not released into the thorax) of length of pleura as far as articulating line, whereas in C. divergens these segments have then tapering lo nothing against the posterior been released forward so the marginal spines

of the facet in a short distance; anterior and appear on the first pygidial segment. This is posterior pleural ribs of equal length; pleural reinforced by the pleural furrows in front of the extremities with free spines (as shown by extent spine running to the margin in C. adatnsensis. of doublure on internal mould), with large The variation between second and third facets over full width and occupying full length pygidial segment being macropleural in this

for distal half, half as wide as fixed pleurae; species indicates that it is not an important prominent processes at lateral articulating feature and that the first segment being

points. macropleural in C. divergens is a relatively Pygidium subtriangular to semicircular, of minor distinction phylogenetically. We con- moderate convexity; axis of seven (or eight in sider it a specific taxobase and further the larger specimens) rings and short terminus, pleural furrows and posteriorly turned anterior tapering to rounded posterior, reaching close border furrow are considered generic tax- but not quite to the inner edge of the doublure, obases. For this reason we consider transaxial furrows transverse, progressively Perischodory Raymond, 1937 and Evansaspis shallower posteriorly; pleural areas convex, Kobayashi, 1955 belong to a separate lineage with well impressed pleural furrows becoming within which they may be congeneric, despite less distinct and narrower posteriorly and not Berg & Ross (1959, p. 1 14), by analogy with C. extending onto the border region; anterior divergens and C. adatnsensis in their lineage. border furrow (i.e. first pleural furrow) very With the origin of pygidial marginal spines as well impressed especially laterally behind the incorporated macropleural segments in mind, long narrow sloping and indistinct facet, curv- better understanding of species relationships in ing strongly back in this area and running to the these groups may be achieved. TREMADOC TR1LOB1TES FROM THE FLORENTINE VALLEY 13

The considerable variation among available smoothly abaxially but never transverse (always

specimens of C. adamsensis is partly due to in- oblique back) then curving smoothly into an ex- traspecific variation and partly due to distortion sagittal line to meet posterior margin at right after burial. The latter is easily recognised in angle; posterior margin transverse. Librigena the transverse or elongate pygidial shape but long and relatively narrow, of low convexity the former is more difficult to discern. Position like the cranidium; eye socle vertical, low, of the pygidial marginal spines is variable be- defined below by the change of slope onto the tween the second and third pygidial segments flat genal field but also with a wide shallow fur- and the structure of the lp and 2p glabellar fur- row around its base; border furrow broad and rows is also variable from being two discrete very shallow, fading out anteriorly, swinging furrows to being a single Y-shaped furrow but adaxially into the posterior border furrow well this latter feature may change during growth. before base of genal spine; border narrow, The identity of lp and 2p combined into one weakly convex, of uniform width, with some

rather than a single Y-shaped lp is clear. weak longitudinal terrace lines near posterior; genal spine short, tapering strongly, with fine Family ASAPHIDAE Burmeister, 1843 longitudinal terrace lines extending along it, Asaphellus Callaway, 1877 continuing the line of the lateral margin of the Type species (by original designation): Asaphus cheek to its tip. Hypostome incompletely homfrayi Salter, 1866. known from only one specimen (PI. 6, fig. 10). Median body broadest at posterior of the Asaphellus cf. sp. A. trinodosus Chang, 1949 anterior wings, subcircular, of low convexity, Plate 4, figure 12; plate 6, figures 1-12 with fine ornament of concentric terrace lines Material: UTGD95877, 95895. 95917, 96002, about an anteromedian point; posterior lobe 96005, 96032, 98111, 98117, 98137 and 122536 only 0.2 of length of median body; median fur- row as two oblique lateral clefts, connected to to 122539 all from NMVPL1602. lateral border furrow by very much shallower Description: Cranidium of extremely low con- more exsagittal furrow; anterior border flat, vexity, without obvious furrows; glabella with gently arched anterior margin; posterior barely outlined by an extremely subtle change border short, convex, isolated by longer well of slope onto the cheeks, broad at base (ap- impressed border furrow, with median prox. 0.5 cranidial width) tapering forward, elongation. about 0.83 of cranidial length, with low incon- Pygidium of low convexity, with poorly im- spicuous median node 0.16 of crandial length pressed furrows, semicircular or just slightly from posterior margin; occipital furrow barely more transverse in dorsal view; axis broadly evident, very near posterior margin; cheeks nar- convex in anterior profile, flat in lateral profile, row, with narrowest point at anterior of of nine rings plus posteriorly rounded terminus, palpebral lobes; palpebral lobes flat, situated rings becoming shorter and less well defined with anterior of lobe at midlength of posteriorly, tapering strongly along anterior cranidium, comparatively long, broadly ar- three or four rings then tapering only slightly if cuate; preglabellar area flat; posterior limb at all, apparently widening again at terminus in downsloping abaxially, with long extremely some specimens; transaxial furrows transverse, shallow posterior border furrow parallel to and with slightly deeper apodemal pits laterally, ex- close to the posterior margin, with blunt lateral tending to inner edge of doublure; pleural areas margin at facial suture; facial suture iso- with extremely shallow pleural and interpleural telliform, hardly diverging forward of the furrows visible on a few specimens; axial fur- palpebral lobes, with widest point forward of row not impressed, marked by small change of palpebral lobes well behind glabellar anterior, slope from axis to pleural area; anterior border curving smoothly forward to the ogive in the furrow well impressed behind lateral articu- midline, running straight back from rear of lating process, fading out about halfway along palpebral lobe for short distance then curving width of articulating facet, straight, sloping a 14 P. A. JELL AND H. STMT

little to posterior abaxially; facet steep, wide, Material available: Some 40 or 50 fragmentary flat, longest near middle of doublure; border and distorted specimens are available from furrow very wide and shallow, parallel to NMVPL1601 including UTGD95994, 98095, border, finishing against facet; doubleure 98102 and 122540 to 122551. almost as wide as anterior of axis, relatively Diagnosis: Ekeraspid with very low convexity, wide, with distinct, parallel, continuous terrace axial furrow extremely poorly impressed; lines. glabella with rounded anterior, waisted at level of palpebral lobes; palpebral lobes small, Remarks: This material is assigned to wide, semicircular, Asaphellus rather than Megistaspis on the basis situated behind midlength of of its long glabella, almost effaced axial furrow, cranidium; facial suture diverging forward of larger eyes, and different hypostomcs. Within palpebral lobes, concave forward of palpebral lobe to widest point, sigmoidal Asaphellus it is related to a group of Tremadoc behind palpebral species from Argentina (/I. catamarcensis lobe, meeting posterior margin at Kobayashi, 1935 (see Harrington & Lean/a, large angle, as it runs posteroaxially. Free cheek with 1957, p. 147), A. jujuanus Harrington & Lean- long genal spine. Hypostome highly con- za, 1957, and A. hojanus Harrington & Lean- vex, with complete rounded posterior margin, za, 1957), from Korea (A. tornko/ensis with widest point near midlength. Pygidium Kobayashi, 1934) and from China {A. c/iangi sublriangular, with long terminal spine decreas- Sheng, 1958. A. inflatus Lu, 1959, A. ing in length with growth; pleural and in- trinodosus Chang, 1949, A. praelrinudosus Lu, terpleural furrows weakly impressed on 1976 among others). Of this array of virtually anterior segments. indistinguishable species the Tasmanian Description: This description only refers to ad- material seems most closely comparable with ditions or modifications to that of Kobayashi A. trinodosus in so far as subtle swellings are (1955, p. 442). Occipital furrow evident only on barely apparent just behind the palpebral lobes internal moulds, extremely shallow, relatively in a similar position to the more obvious ones very close to posterior margin. Palpebral lobe of the Chinese species. The course of the facial comparatively short, close to glabella, wide, suture just behind the palpebral lobe seems semicircular, flat but slightly elevated, situated distinctive of the Tasmanian material but this near midlength of glabella and behind hardly seems sufficient to erect a species midlength of cranidium. Facial suture diverging especially within such a difficult taxonomic slightly forward from palpebral lobes, with complex of essentially contemporary species. widest point forward of glabellar anterior, then anteriorly concave to Megistaspis (Ekeraspis) Tjernvik, 1956 anteromedian point, cur- ving laterally a short distance behind the Type species (by original designation): palpebral lobes, then almost transverse but Plesiomegalaspis (Ekeraspis) armata Tjernvik, always slightly oblique, then curving posterior- 1956. ly to be exsagittal and curving back towards the Megistaspis (Kkeraspis) euclides (Walcott, axis near posterior margin to give rounded 1925) margin to extremity of posterior cephalic limb. Librigena with Plate 7, figures 1-15 broad flat genal field, without border furrow; eye socle low, vertical, promi- 1925 Xetwslegium euclides Walcolt, p. 126, pi. 24, ligs nent; genal spine long, almost circular in sec- 13. 14. tion but with strong ridge running down ventral 1925 Xenoslegium albertensis Walcott, p. 125, pi. 24, figs 10, II. side, with distal part in exsagittal line; 1955 Kavseraspis (?) euclides Walcolt; Kobayashi, 442 p. doublure, wide, elongate anteriorly, in trans- pi. 4, ligs 4-12; pi. 5, figs 8-10. verse section slightly upturned adaxially to re- Syntypes: USNM70364 and 70365 (figured by main flush against dorsal exoskeleton, with Walcott, 1925, pi. 24, figs 13, 14) from Mons strong parallel terrace lines from base of genal Formation, Sawback Range, British Columbia. spine to median suture of isotelliform suture TREMADOC IRIIOBITES I ROM II THL ORENTINE VAI I B> I?

pattern, with terrace lines diverging and in- of cranidia. The Tasmanian material, where creasing in number by intercalation anteriorly, only one asaphid species occurs al (he horizon Hypostome convex, subquadrate, covered with in question, confirms his association and all terrace lines more or less concentric about an thai remains is for this lype of cephalon to be anteromedian point on the high part of the me- discovered at the lype locality. However, mor- dian body; median body longer than wide, phology of the species is now well established. rounded anteriorly, with well-impressed me- Kobayashi (1955) recognised the alliance of (he

j dian furrow dividing it into large anterior lobe species with Mi i>istuspis bul assigned it lo and very short low posterior lobe; median fur- Kayseraspis Harrington, 1938 without com- row at high angle to transverse line laterally, menting on the reasons. The parallel-sided not continuous across axis; anterior wings short glabella, shorter glabella, more posterior eyes, almost vertical, well ornamented; shoulder triangular pygidium and longer stouter wide, fairly Hat, tapering strongly both forward posterior spine distinguish this species from and back; border furrow well impressed lateral- Kayseraspis, ly, not connected directly 10 anterior border family DIKELOKEPHALINIDAE furrow, running mosl distinctly into median Kobayashi, 1936 furrow but also connected by .shallow furrow This family was placed with with posterior border furrow; posterior margin the asaphids by Harrington et al. (1959) probably by complete, short medially, covered with terrace asso- ciation with the Taihungshaniidae which lines; anterior border furrow cutting across were correctly placed in the Asaphoidea. The Dikel- anterior wing lo margin in front of lateral okephalinidae have a glabella usually notch. Thorax of six or more segments (com- about 0.6-0.7 of cranidial length while pleie specimen not available); pleural furrow asaphids have a much longer glabella. In the pygidium the beginning at anterior in axial furrow, in critical Laxobase is the altitude of pleural fur- midlength for most of its course, lading out rows- relatively transverse in asaphids bul about the midwidth of the free pleura, deepest strongly curved backwards in the dikel- crossing articulating line; thorax typically okephalinids. The asaphid. Taihungshaniidae and Dikelokephalinidae both possess a pair of Pygidium triangular, with long posterior pygiclial marginal spines bul these are spine becoming relatively shorter with growth; homeomorphous structures shared with a greal axis long, slightly tapering, almost parallel

many other trilobites as well. 1 1 appears far sided, with seven barely discernible rings and a more likely thai the Dikelokephalinidae evolved long axis consisting presumably of several more from l he Dikelocephalidae as suggested by rings that are not defined; pleural fields with Kobayashi (1936, 1960). The brief remark bv poorly impressed pleural furrows anteriorly, Fortey and Peel (1983, p. 54) dial the with even fainter interpleural furrows on the Dikelokephalinidae are probably related lo the ribs, with well impressed anterior border fur- Ceratopygacea would need some amplification row identical with the thoracic pleural furrows; if it is to be taken seriously especially in light of articulating facet wide, steeply inclined; border l he prominent occipital node (PI. fig. furrow not impressed; doublure of moderate 8, 7); position of the node, forward of the occipital width, with well developed parallel and furrow rather than on the occipital ring, was anastamosing terrace lines, close beneath dorsal used lo relate Macropyge to the Ceratopygacea exoskelelon; posterior spine circular in section, (Owens el al., 1982) so some discussion of the connected lo posterior of axis by low ridge importance of this feature would seem ap- across border area in some specimens. propriate. The Hungaiidae Raymond, 1924 may have a similar origin and these two derived Remarks: This species was erected by Walcolt families could be synonymous. for pygidia and a hypostome and the interpreta- Dikelokephalina tion of the cephalon depends upon Kobayashi's Br^gger, 1896 (1955, pi. 4, figs 5, 10; pi. 5, fig. 8) assignment Type specks (designated Vogdes, 1925): Cen- 16 P. A. JELL AND B. STAIT

tropleura ? dkraeura Angelin, 1854 from the 1981), which family is distinguished by the Tremadocian Ceratopyge Limestone of Gamle- asaphoid glabella and pygidial pleural furrows byen, Oslo, Norway. being transverse or almost so; in Taihungshania itself, the pleural furrows are transverse in Diagnosis: Large isopygous trilobites of low juvenile individuals so indicating its asaphoid convexity. Glabella convex, anteriorly round- affinities — their posterior sweep in adults is a ed, with three pairs of lateral glabellar furrows; secondary development. The posterior spines posterior pair being forked adaxially, none may reasonably be considered homeomor- reaching the axial furrow. Frontal area 0.3 to phous. 0.5 length of cranidium, together with anterior Within the family the position of the parts of fixed cheeks forming an extensive flat posterior spines distinguishes Dikelokephalina anterior area. Palpebral lobes of medium to from all other genera. large size, at or behind midlength of glabella. Fixed cheeks approximately half glabellar Age and Distribution: Late Tremadoc; Nor- width at level of midlength of palpebral lobe. way, Sweden, Wales, South Korea, Tasmania. Posterior cephalic limb very wide and short. Dikelokephalina asiatica Kobayashi, 1934 Pygidium with long, narrow axis of at least Plate figures 1-8 seven or eight rings. Pleural furrow curved 8, posteriorly, becoming almost exsagittal pos- 1934 Dikelokephalina asialieu Kobavashi, p. 563. pi. 6, teriorly. Border with relatively narrow tigs 1-3. 1934 Dikelokephalina kanaegata semielliptical excavation so that the margin on Kobayashi, p. 564, pi. 6. figs 4, 5. either side of it is extended into a strong spine. 1980 Dikelokephalina sp. nov.; Siait & Laurie, p. 205, lig. 3, appendix 1. Remarks: Affinities of the group of genera to Holotype (by original designation): Cranidium which this genus belong were discussed by figured by Kobayashi (1934, pi. 6, fig. from Kobayashi (1936, 1960) and by Henningsmoen 2) the Clarkella Zone (Late Tremadoc) al Saisho- (1959). As mentioned above the severafgroups ri, South Korea. of genera having spinose pygidia, with which affinities for the Dikelokephalinidae have been Material: Apart from the figured material of inferred, are homeomorphous forms and the Kobayashi the specimens assigned to this true affinities of Dikelokephalina will only be species are all from Faunal Assemblage No. 3 of Stait arrived at by careful plotting of phylogenies at and Laurie on the Gordon Road Sec- the species level. The rarity of Dikelokephalina tion and are numbered UTGD95978-95982, in all its known occurrences suggests that plot- 96689, 122552, 122553. ting of such phylogenies will not be possible for Description of Tasmanian material: Cranidium some time but the Dikelocephalidae seems the of low convexity except for broadly convex family most likely to contain the glabella; ancestral glabella tapering gently forward to stock. rounded anterior, with three pairs of lateral The posterior pygidial spines are the most glabellar furrows adjacent to but separated distinctive feature of the genus and their from the axial furrow, furrow lp bifurcate absence from any described species or the in- adaxially, elongate transversely, running very ability to observe the morphology of that part slightly to the posterior adaxially, not very of the exoskeleton (e.g. for D. parva deep, and with very gentle sides, its anterior Kobayashi, 1960 and D. conica Kobayashi, branch shorter and less elongate and running 1960) must throw doubt on assignment to the forward adaxially; furrows 2p and 3p rounded genus. Another genus with similar posterior pits very close to the axial furrow; 3p being just pygidial border morphology is Asaphelina behind junction of eye ridge and Bergeron axial furrow; 1889, the type species of which was occipital furrow well impressed, with deeper originally included in Dikelokephalina by short wide apodemal pits reaching Br^gger the axial fur- (1896). However, that genus is referred row, medially shallowing and curving slightly to the Taihungshaniidae (Court essole et al., forward; occipital ring of approximately 17 IKl iMADOC l'Rll OI!l IIS I ROM III! II OKI Nl INI V Al I IA

uniform length, with prominenl median tuber- defined bul a fairly wide flat marginal area that cle near midlengih, with transverse posterior tapers forward is weakly defined by change ol margin; extremely weak development ol'alaeon slope from pleural areas and ends of pleural one specimen (PI. 8, lig. 7); preglabellar length furrows; posteriorly is a long but narrow ex- 0.3 of cephalic length; anterior border furrow cavation in the border with, as a consequence, a very vaguely apparent just forward of the pan ol sharp marginal spines beside it; bordei midlength of the preglabellar length; all area in laised up to the margin ol this excavation; on

front o\' glabella flat; fixed cheeks narrow and l he border and possibly over I he whole pleural

flat; palpebral lobes prominent, with semicir- area are very faint, irregular transverse lerracc cular outer margin, with anterioi end much lines mosi numerous at the margin decreasing closet to glabella than posterior end, sloping up in number adaxially; doublure wide, very close abaxially; palpebral furrow not well impressed beneath dorsal exoskeleton throughout being but nevertheless distinct, parallel to outei upturned near its mid-width to the pleural areas margin o\' lobe medially but swinging around and being upturned wilh the dorsal exoskeleion both ends of lobe to facial suture; facial suture around the posterioi excavation, with strong running forward from palpebral lobe in a broad terrace lines parallel io the margin ovei the en- curve bui the palpebral lobe extends laterally tire width; inner edge o[ doublure wilh marked beyond widest extent of anterioi pari of facial excavation posteromedial around the rear of

suture; posteriorly, facial suture running I he axis. transversely out tor 0.75 of basal glabella) Remarks; The material illustrated by Kobay width before curving sharply posteriorly to the ashi (1934) is relatively incomplete making margin; posterior cephalic limb wide and short, comparison with new collections difficult. with uniform posterioi bolder furrow running However, introduction of a new specific name across its anterior part to the facial suture when all observable features between the before the suture curves back; posterioi bordei Korean and Tasmanian specimens are so clearly of uniform length, convex in lateral profile and identical would be irresponsible. Although the downturned abaxially, with prominent gently margin ol the two figured Korean cranidia curved terrace lines running mainlv in the ex (kobavashi 1934, pi. 6, tigs 2, 3) are very in- sagittal direction; posterior margin transverse complete his dashed Suggestions for Iheu pOSi adaxially but curving slightly back abaxially. lions seem quite reasonable. However, Ins Pygidium of low convexity, with axis stan- dashed Outline for ihe hololype pygidium of /). ding only slightly above pleurae in anterior kanaegata (Kobavashi, 1934, pi. 6, fig. S) ap-

al I he lefl profile; length to widih ratio unknown, ai peals lo have a right angle bend lieulaiing half-ring very Short; axis of live well anterolateral comer that is unlikely lo be coi usiulicu defined rings and a long poorly divided ter- reel, the pygidium assigned lo I), by are very in- minus thai includes ai least four more rings and (Kobayashi, 1934, pi. 6, hgs 2, 3) of suggestions for their posi- the terminal piece which is at I he inner edge complete his dashed separated by the doublure, quite wide anteriorly, tapering have narrow raised pleural ribs surface is cor- markedly in anterior halt; rings ol uniform wide interspaces. If the external should be length; wide, sharp, pooily defined, apodemal rectly described ihen this specimen the generic level from the pils laterally in transaxial furrows visible only Separated at leasl al more likely to be an on internal moulds; axial luriow evident only associated cranidia. H is far of a juvenile specimen and its as a change of slope and change of direction of internal mould of is likely to be more in line furrows; pleural areas crossed by live pairs external morphology more pygidia assigned lo J), kanaegata. well impressed pleural furrows becoming with Ihe two occur together al Makkol, c.xsagilial in direction, closer loyelhei ami As Ihe Iwo species considering the stales of shallower towards the posterior; pleural fur- South Korea and after seeing the rows extend almost to the margin, shallowing preservation bul without actually consider the two species of markedly to nothing abaxial to the inner material we lo be synonymous. Only Ihe margin ol the doublure; bordei not clearly Kobayashi (1934) P. A. JELL AND B. STAIT

structure and position of the palpebral lobe Ogygites (?) annamensis Mansuy, 1920 (Early Arenig; North may appear lo distinguish the Tasmanian Dong-san, Vietnam). Taihungshaniu wetleri Sheng, 1934 and Taihungshama bul species the posterior course of ihe facial welleri var. breviea Sheng, 1934 (Tremadoc; Chekiang, suture was interpreted by Kobayashi and may China). Asaphopsis be in error. The holotype and one Tasmanian granutatus Hsu, 1948, A. planispiniger Hsu, 1948, A. angltStigenatUS Hsu, 1948, A. immants Hsu, specimen show incipient alar development on 1948, Temnoura grandispmifer Hsu, 1948, and Tem- one side only. One feature which docs appear nowa alula Hsu, 1948 all from the Late Tremadoc or Early Arenig of western Hupeh, China. distinctive is the border region sloping lo down Asaphopsis semicircularis l.u, 1975, A. angulatusLu, 1975, the margin of (he posterior excavalion in A, (?) abnormii l.u, 1975, and A. yaokoulzeensis Lu, 1975, all from Ihe Tremadoc or earliest Arenig of western Kobayashi's material (1934, pi. 6, fig. 4) Hupeh or southern Sichuan. whereas il is upturned in the Tasmanian Asaphopsis wuchuunensis Yin in Yin & Li, 1978 specimens. This is considered lo be inlraspecific (Tremadoc; Guizhou, China) Asaphopsis yinjiangensis Yin in Yin & Li, 1978 (Tremadoc; variation if it is real but the exoskelclon of this Guizhou, China) species is quite flexible and the difference may Asaphopsis sanchaqiensis Lu in Zhou et a/., 1978 be due to preservalional history. Further collec- (Tremadoc; southern China) Asaphopsis laiiiimhaius Lu in Lu el at., 1976 (Tremadoc; tion and study of material from the type locali- southern China) ty is urgently needed lo clarify this species. Asaphopsis hanyuane/lSis Li, I97K (Tremadoc; Sichuan, Dikelokephalina asiutica may be distinguished China) AsapffOpsis vanjinensis from the type Li, 1978 (Tremadoc; Sichuan, species by its broader sub- China) triangular rather than subquadrate pygidium, Asaphopsis ovoideus Xia, 1978 (Tremadoc; Hupeh, China) Asaphopsis budabnensis Balashova, Ihe closer position of the posterior spines, 1966 (Early Ordovi- cian; Russian Platform) straight pleural furrows, very weak alae, anteriorly placed posterior border furrow on Discussion: Asaphopsoides was erected to cranidium and less divergent more rounded separate Dicellocephalus ? villebruni from facial suture in front of the palpebral lobe. Asaphopsis Mansuy, 1920 where it had Asaphopsoides Hupe, 195? previously been placed (Kobayashi, 1936, Type species (by original designation): 1940). In doing so Hupe (1955) quoted features of the cranidium as Dicellocephalus ? villebruni Bergeron, 1895 generic taxobases. He, therefore, did from the earliest Arenig of Monlagne Noire, not have the type species of southern France. Asaphopsis in mind as A. jacobi is known only from fragmentary pygidia and thoracic Diagnosis: Dikelokephalinid with preglabellar segments (Mansuy, 1920, pi. 1, fig. 7a-g). length 0.3 or more of cephalic length; strong, Although the concept of Asaphopsis has for wide, diagonally directed, linear apodemes in almost 40 years rested upon Kobayashi's species preglabellar furrow. Pygidial axis may contain A. nakamurai it is essential that Mansuy's 6 to 16 rings; pleural furrows swept backwards (1920) type species be reappraised for a stricter with posterior pleural furrows at very low angle generic basis. Of the pygidia figured by Mansuy to sagittal line; pygidial border moderately to only one (1920, pi. 1, fig. 7a) clearly shows the very wide, without border furrow but with at marginal spine and should be considered the least a pair of variably sized, prominent, flat lectotype. Both this and the other interpretable spines placed relatively widely apart at specimen (Mansuy, 1920, pi. 1, fig. 7b) posterolateral corners. have their pleural furrows running transversely near Species content of genus: A. villebruni type species. ihe anterior and at only a small angle (less than See Thoral, 1935 and Courtessole el al., 19X1. 20°) to the transverse line posteriorly. This Dikelocephalus Jtorentiriensis lithe ridge, 1905 (Early feature alone suggests Arenig; Tasmania) see below. that the type is not con- generic [= Asaphopsis juneensis Kobayashi, 1940a and A. (?) with any other species so far referred to grackuslatus Kobayashi, 1940] Asaphopsis. This type of pleural structure is Asaphopsis twkamurai Kobayashi, 1936 (Early Ordovician; Dolen, Soulh Korea). much more reminiscent of asaphoid trilobites Asaphus elegantulus Gorlani, 1934 (Early Ordovician; (e.g. Asaphellina of the Taihungshaniidae). Chisil Pass, Karakorum). The marginal spines of the Taihungshaniidae TREMADOC TRILOBITES FROM THE FLORENTINE VALLEY 19

and Dikelokephalinidae probably developed Dainellicaada Kobayashi, 1960 is also referred homeomorphously. The distinction is most evi- to Asaphopsoides as none of the features men- dent in glabellar features of the cranidium but tioned as diagnostic by Kobayashi (1936, p. even in the pygidium, the Taihungshaniidae 177; 1960, p. 253) are valid. His indication that have much more transverse pleural furrows in the marginal spine arises from the first pygidial adult Asaphellina Bergeron, 1889 (see segment is not substantiated and the position of Courtessole et al., 1981, pi. 7, figs 1, 3, 6) and the abaxial end of the fourth pleural furrow, in juvenile Taihungshania Sun, 1931 (see aiming at the margin just behind the base of the Courtessole el al., 1981, pi. 5, figs 1-6, 8, 9). spine, is identical with that in several Chinese Taking these data into account Asaphopsis species of Asaphopsoides as well as A. floren- should be restricted to A. jacobi and probably tinensis. Dainellicauda is a junior subjective A. reedi which may be synonymous with the synonym of Asaphopsoides. type species and that genus should be removed Distribution and age: Late Tremadoc to Arenig to a tentative placement in the Taihung- of China; Early Arenig of France and shaniidae pending collection of cephala of the Tasmania; Early Ordovican of Russia, South type species. Korea, northern Vietnam and Pakistan. The glabellar features of Asaphopsoides Asaphopsoides florentinensis (Etheridge, 1905) villebruni are illustrated by Thoral (1935, pi. 23, figs 5, 6) and Courtessole et al. (1981, pi. 4, Plate 2, figure 15; plate 9, figures 1-11; plate 10,

fig. 5); the latter authors point out that they figures 1-10 have been incorrectly illustrated in general text- books. Certainly the illustration in the Treatise 1405 Dtkeloceplialus florentinensis Etheridge, p. 24, pi. 10, fig. 4. (Harrington ei al., 1959, fig. 268-6a) is highly 1914 Dikelokephulinu florentinensis (Etheridge); Walcott, inaccurate. However, the illustration of p. 350. 1936 Taihungshania florentinensis (Etheridge); Kobay- Courtessole et al. (1981) is not identical with the ashi, p. 179, pi. 20, fig. 16 (not fig. 15). figures offered pi. figs by Thoral (1935, 23, 5, 6) 1936 Asaphopsis florentinensis (Etheridge); Kobayashi, p. and it may very well be that the bulge in the side 177. p|. 21, tig. 5. 1940 Asaphopsis juneensis Kobayashi, p. 64, pi. 11, figs of the glabella adjacent to the prominent pit in 6-9. the glabella (presumably furrow 2" of 1940 Asaphopsis /?) grucicostatus Kobayashi, p. 65, pi. 11, fig. 10. Courtessole et al. 1981, p. 21) is an artefact of 1974 "Asaphopsis" juneensis Kobayashi; Corbett & compression in the sediment. There is indica- Banks, pi. 1, figs 14. 17, 18, 22, 23, 24; pi. 2, fig. 9. tion from many of the illustrated specimens of 19X0 Asaphopsis juneensis Kobayashi; Slail & Laurie, p. 207. this genus (e.g. Lu, 1975, pis 26, 27) that the 1980 Asaphopsis sp. nov. Stait & Laurie, p. 207. exoskeleton was very thin and had a certain Holotype (by monotypy): AMF9282 a damaged amount of flexibility so generic taxobases and distorted pygidium from the Florentine should not be cited as such detailed features. Valley, southwestern Tasmania at a site near Variations in the shape, size and position of 'The Gap' (fide Corbett & Banks, 1974, p. 219). lateral glabellar furrows should be used at pre- sent only as species taxobases in this trilobite Other material: More than fifty dissociated ex- family. As significant features listed in the oskelelal parts from 'The Gap' and from the diagnosis are remarkably uniform, where Gordon Road Section. Asaphopsis sp. nov. and observed, through the species listed above, the A. juneensis of Stait and Laurie (1980, fig. 3) many species previously referred to Asaphopsis and A. juneensis of Corbett and Banks (1974) should now be referred to Asaphopsoides. The were available (including UTGD80995, 80999, long preglabellar part of the cephalon, marked 81001, 81019, 81086, 96022, 96036, 96038, linear apodemes in preglabellar furrow, 96650, 96652, 98053, 98060, 98075, 122525, posteriorly swung pygidial pleural furrows, and 122555-122561). fairly widely separated marginal spines appear to be the most significant generic taxobases. Diagnosis: Member of Asaphopsoides with The single pygidium upon which is based parallel-sided to anteriorly tapering glabella TREMADOC TR1LOB1TES FROM THE FLORENTINE VALLEY 21

ternal mould with its convexity reversed during Family HARPED1DAE Hawle & Corda, 1847 or after burial; such specimens are known in the Scotoharpes Lamont, 1948 available collection. Therefore the short pleural Type species (by original designation): ribs are actually moulds of the pleural furrows Scotoharpes domina Lamont, 1948 from the and this is clear on the proximal doublure. Upper Llandovery of Scotland. Although one of his pygidia shows at least 9 the brief original description pygidial axial rings this is a notoriously variable Remarks: Despite appraisal of that feature likely to be greater on internal moulds. of the type species a detailed species, including illustration of the holotype is It seems most likely that, given the ubiquitous Norford also tectonic deformation of specimens from the now available (Norford, 1973). Selenoharpes Whittington, 1950 and Florentine Valley Formation, Asaphupsoides is recognised 1950 as junior sub- represented in that formation by a single Aristoharpes Whittington, jective synonyms of Scotoharpes. Although species. Certainly material available to us does recognise stratigraphically useful not indicate otherwise. efforts to generic morphotypes are laudable the relatively Of foreign species A. villebruni is very close large collections of the Tasmanian species and to the Tasmanian species but its preglabellar (Jell, 1985) suggesting that length appears (based on only two specimens of Australoharpes cephalic shape and development of alae are figured by Thoral in 1935) to be less, its with growth make the generic concepts palpebral lobes are proportionally longer and variable number of harpedid genera appear to be the pygidium has different transaxial furrows of a too typological in their definition. Accordingly and very slightly longer marginal spines. accept Norford's synonymy and assign the However, these are minor differences that may we new Tasmanian species to Scotoharpes because ultimately prove to be of less than specific of the close comparison in all observable significance. A. nakamurai has tiny palpebral features. The extent of the girder along the pro- lobes situated well forward and the pygidial longation and occurrence of slightly coarser marginal spines are situated well back (i.e. the pits along the girder and the upper and lower fourth pleural furrow, if continued, reaches the rims are important features in common. margin well in front of the spine). A. annamen- sis and A. elegantulus are too poorly known for Seotoharpes lauriei sp. nov. comparison. Of Chinese species, almost all are Plate 11, figures 4-14 clearly distinguished by their long slender marginal spines but A. planispiniger appears Etymology: The species is named for John very close to A. floreniinensis although the rear Laurie who was involved in the original of the hypostome appears to have a slightly biostratigraphic study of the Gordon River different configuration (Lu, 1975, pi. 26, fig. Road section and helped collect much of the 20), pygidial pleural furrows extend across the material. border almost to the margin and the third Material: Holotype UTGD121586, paratypes rather than the fourth pleural furrow reaches UTGD95922, 96007, 96008, 96010, 121496, and spine (Lu the margin just behind the marginal 122566-122569 all from NMVPL1602. in Luetal., 1965, pi. Ill, fig. 14). Diagnosis: Member of Scotoharpes with only A number of juvenile cranidia and pygidia very faint lp furrow evident on glabella, an oc- are available but show no significant differences cipital node, very faint alae evident as extreme- except perhaps they have more from the adults all, with ly weak depressions or no! evident at relief, more elevated palpebral lobes and fur- short posteriorly directed spine on posterior of rows, and in at least one specimen the fifth prolongation. pleural furrow reaches the margin just behind Description: Cephalon subcircular to subovate, the spine. This may be interpreted as the final moderately convex. Glabella narrow (less than meraspid stage; as one more thoracic segment of cephalic width), and approximately moves out into the thorax so the fourth furrow 20% half cephalic length (without prolongation), will be adjacent to the spine. 20 P. A. JELL AND H. STA1T

broadly rounded anleriorly; palpebral lobes of wider and deeper laterally, running prominent- moderate size, highly arcuate laterally, situated ly into well-impressed middle furrow, almost at or behind glabellar midlcngth; pygidium with imperceptible across shoulder past short narrow tapering axis of at least seven rings and posterior lobe of median body, well impressed a long terminal piece which may represent posterolaterally but shallowing posteromedial- several more rings; marginal spines small, in- ly; border short and continuous across midline

conspicuous, widely separated; posterior anteriorly, expanding laterally into large flat margin broadly rounded. triangular wings, contracting to a narrow ridge near midlength of anterior lobe of median Description: Up to very large size (pygidia body, expanding again posteriorly into a flat ex- 80 mm wide known). Cranidia relatively flat ex- pansive shoulder approximately as wide as the cept for convex glabella; glabella with lateral anterior wing and tapering strongly into a short margins parallel-sided to slightly converging rim-like posterior border. forward; glabellar anterior broadly rounded Pygidium relatively flat with only real con- with deeper wide apodemal pits (fossulae) in the vexity in axis, pleural areas sloping gently to preglabellar furrow laterally making those parts margin with no border furrow impressed; axis of the furrow quite straight; three pairs of well straight-sided, tapering posteriorly, with well impressed lateral glabellar furrows on the steep rounded posterior at inner edge of doublure, a lateral slope of the glabella, close to but not considerable distance from margin, with confluent with axial furrow; occipital furrow variable (i.e. between specimens and between distinct but shallow; occipital ring of uniform internal and external surfaces) number of rings length, with low median node at midlength; visible (6-12 in available material); transaxial preglabellar part of cranidium (considered to be furrows straight, weakly impressed but distinct greatly expanded anterior border as doublure becoming less so posteriorly, with only very extends back to front of glabella) flat with faint weak apodemal depressions laterally away from epiborder furrow evident on some individuals, the axial furrow; pleural area with at least 7 with transverse ridge evident at inner margin of (sometimes a weak eighth) pleural furrows that doublure (possibly compaction feature) on recurve posteriorly approaching the border and other specimens; palpebral lobe prominently are almost exsagittal posteriorly; fourth pleural bulging laterally, slightly raised above rest of furrow if continued in regular curve meets cheek, relatively close to glabella; palpebral margin just behind the spine; border wide, not furrow not parallel to lateral margin of lobe but crossed by pleural furrows (may be an artefact rather almost straight, nearly exsagittal diverg- of flattening after burial); margin smoothly ing slightly posteriorly and rather shallow- rounded, with pair of short flat or weakly con- facial sutures anterior to eye diverging forward vex posterolateral spines, broadly rounded and to converge again forward of the midlength of sometimes with a pair of very wide short bulges border in well rounded arch to meet the margin symmetrically placed about the midline be- apparently not far from midline; posterior tween the spines (pi. 10, figs 4, 7); doublure cephalic limb very wide, with long posterior quite wide and ornamented with continuous border elongating laterally, well impressed parallel terrace lines most numerous near the transverse border furrow shallowing and inner edge. shortening laterally and short band of fixed cheek before facial suture that is transverse Remarks: Every specimen observed is distorted from rear of palpebral lobe until it curves to some degree and almost all previous observa- sharply to the posterior where it meets margin tions have been made on internal moulds. Each at right angles. of the features quoted by Kobayashi (1940) as Hypostome large, more or less equidimen- distinguishing his Tasmanian specimen from sional median body markedly convex at Etheridge's (1905) is greatly influenced by one anterior where it has almost vertical slope in the of these factors. Kobayashi's A. ? gracicostatus midline; border furrow very short anteriorly, (1940, pi. 11, fig. 10) is almost certainly an ex- .

22 P. A. JELL AND B. STAIT

moderately convex, iapering gently forward to for anterior border furrow, distinct articulating narrowly rounded anLerior, with extremely facet developed; border furrow broad and

I aim lp furrow the only glabellar furrow pre- shallow but distinct; border very narrow, taper- sent. Axial furrow well impressed laterally but ing posteriorly, horizontal. little more than a change of slope in front of the glabella, also shallower posteriorly just in front Remarks: Svotoharpes lauriei may be dis- of the border furrow where alae are situated. tinguished from S. domina by the shape of Occipital furrow shallow with gentle anterior its prolongation, and its weak alar develop-

and posterior slopes into it. Occipital ring of ment; from .V. latior (Poulsen, 1934) by its uniform length, rising to the highest point al glabellar shape, weak alae and prominent the posterior, with high median tubercle stan- girder; from S. vetuslus Zhou & Zhang, 1978 ding like a post on the anterior of the ring. Alae by the prominent alae of that species although small and very subtly depressed if at all evident. thai species is too poorly known for useful Eye tubercles just behind anterior of glabella, comparison; it differs from all other species of large and round, elevated almost to height of the genus in its weaker alae but resembles glabellar rear; eye ridge transverse, straight, juvenile specimens of S. Ionia (Lane, 1972) (see long and low in section, joining axial furrow Norford, 1973, pi. 3, fig. 6) in this as well as

but not crossing it just behind glabellar most other features. This last resemblance in- anterior; weak fossular depression in front of dicates its ancestral relationship to Lane's eye ridge. Preglabellar field and anterior cheek Silurian species. roll about equal in length, together sloping very family PILEKIIDAE Sdzuy, 1955 gently down to the brim, cheek roll of uniform Although Lane (1971) advocated width except posterolateral^ where it is extend- inclusion of ed in both directions along the posterior margin this group as a subfamily of the Cheiruridae we

prefer to it into a triangular area. Girder prominent as a retain as a separate family mainly on the basis the ventrally projecting ridge, meeting inner rim al of type of thoracic pleural furrows about one-third of the distance from the and on the commonly four segments in the posterior of the occipital ring to the tip of the pygidium. This arrangement is also favoured to brim prolongation, represented on upper accommodate a number of phylogenetic lamella by broad caecum from which issue possibilities that will be discussed in another smaller diameter radial caeca that are separated paper (Jell, 1985). immediately against the girder by pits of the Pilekiidae gen. et sp. nov. same diameter as those elsewhere. Brim flat to Plate 12, figures 1-4 gently concave, covered by radially arranged anastamosing caeca! network, caeca separated by pits of fairly uniform size, pits against rim Material: Two cranidia (UTGD 122570 and also of same size; brim prolongation tapers 122571) and two pygidia (UTGD122572 and posteriorly as the outer rim curves adaxially 122573) all external moulds from NMVPL1601 towards (he posterior, with spine of circular section on posterior extremity, including spine Description: Glabella almost as wide as long; as long as axial length of cephalon. tapering only slightly forward from widest Thorax of 14 or more segments, tapering point at furrow lp, with broadly rounded posteriorly; axis tapering markedly towards the anterior, highly convex in anterior profile, with posterior, just slightly narrower than width of three pairs of lateral glabellar furrows; each pleuron. glabellar furrows wide, slit-like, almost Pygidium transverse, of low convexity; axis transverse or directed back adaxially, dividing tapering markedly, of 7 rings and ter- minute glabella into lobes of equal length except for the minus situated some distance in front border of slightly longer frontal lobe; axial furrow well furrow; axial furrow not impressed, only a impressed, narrow, continuing forward as the change of slope; pleural areas smooth except preglabellar furrow without change; pregla- TREMADOC TRILOBUES FROM THE FLORENTINE VALLEY 23

bellar field absent; anterior border extremely Remarks: This species is closely related to short, convex, like a rope running across the Pilekia but we consider that it will be found to

front of the glabella, elongate a little towards represent a separate genus based on its less facial suture, curved back strongly around bulbous lp glabellar furrow, its lack of a strong anterolateral corners of glabella; palpebral lobe genal or lixigenal spine, the tiny semicircular broad, short, at small angle to exsagittal line, pygidial axial terminus, and the transverse meeting axial furrow just behind level of fur- pleural furrows in front of posterior pleural row 3p, curving evenly back fairly close to the bands that turn sharply back at the base of the axis to near the level of furrow lp, convex and marginal spines. The combination of these

uniform in section throughout; palpebral fur- features separates it from all those assigned to row well impressed, parallel to lobe and curving either Pilekia Barton, 1915 or Parapi/ekia out around posterior of palpebral lobe; fixigena Kobayashi, 1934. behind palpebral lobe as wide as base of Pilekia Barton, 1915 glabella, but quite narrow between palpebral species (by original designation): lobes, sloping down strongly abaxially, with Type CheirurUs apollo Billings, 1860. pitted ornament; facial suture proparian very

short and curving adaxially in front of Pilekia sp. nov. palpebral lobe, running transversely behind Plate 12, figures 8-12 palpebral lobe 10 meet lateral margin at about level of furrow lp; ventral sutures unknown; Material: UTGD95987, 95989, 96664, 122577, posterior border convex both in posterior 122578 all from NMVPL1600. profile and in section with the latter flattening Description: Glabella with widest point near out laterally, becoming elongate laterally and anterior of lobe lp or rear of lobe 2p, with well extended into apparently short (full extent not rounded anterior, with well impressed almost evident on only available specimen) lixigenal transverse occipital furrow becoming slightly spine at the genal angle; posterior border fur- longer medially and with lateral parts running row well impressed, short, of uniform cross- forward from axial furrow, with occipital ring section laterally to beyond the genal angle, only marginally longer than occipital furrow similar to the glabellar furrows in cross-section. and shorter laterally with convex lateral profile Hypostome, rostral plate and thorax not rather than the Halter profile medially, with or- known. nament of coarse tubercles except in furrows; Pygidium small, transverse; axis of four rings lateral glabellar furrows well-impressed, weakly and small semicircular terminus reaching convex forward, becoming shallower shorter posterior margin; rings slightly longer towards and directed posteriorly towards the axis, with posterior, of uniform length, separated by well- long flat bottoms near axial furrow and steep impressed transaxial furrows becoming shal- almost vertical sides, with furrow lp reaching lower towards the posterior; pleural areas back almost to the occipital furrow and crossed by well-impressed pleural and in- isolating a large prominent lp lobe; lobes terpleural furrows; interpleural furrows curved becoming progressively shorter forward with posteriorly and deeper towards margin; pleural anterior lobe being quite short and subrhombic furrows shallowing towards margin and not in shape with arcuate anterior; anterior border curved; posterior pleural band extended into furrow short and deep; anterior border short, short blunt free spine on each segment, turning rising strongly forward, of uniform length on sharply posteriorly at the base of the spine; cranidium; eye ridge running out and slightly fourth segment with very weak pleural furrows, back from axial furrow near level of midlength with its short spines enclosing the axial ter- of lobe 3p, straight, convex in section; fixed minus laterally; all marginal spines directed cheeks wide, subtriangular, with strong re- posteriorly. Surface ofcranidium and pygidium ticulate ornament of caeca! ridges separated by (except in furrows) covered with fine widely- prominent pits and bearing sparsely scattered spaced granules. tubercles on top of the ridges; palpebral lobe 24 P. A. JELL AND li. SI All

available relatively small, curved posteriorly, defined by angle. There is not sufficient material its novelty is promineni Furrow thai extends along rear of lo propose a new specific name but eye ridge; posterior border furrow well- not in doubt. Assignment to Pilekia is based in impressed, becoming slightly longer abaxially, particular, on the enlarged lp lobes and the continuing around genal angle as slightly nar- greatest width of the glabella being near the are rower lateral furrow, beginning in axial furrow anterior of lobe lp but all other features sizes ai occipital furrow not at posterior margin; consistent with this assignment. Relative posterior border short near axial furrow, of pygidial spines seem to separate this material becoming longer and flatter laterally, bearing from any described species of Pilekia. strong posierolalerally directed fixigenal spine Family PLIOMERIDAE Raymond, 1913 (PI. 12, lig. 8b) some distance adaxial to the removed the pilekiids from genal angle; course of facial suture not clear on Whittington (1%1) any specimen. this family and noted that division of the re- was unwarranted. Librigena, rostrum, hypostome, and thorax maining taxa into subfamilies unknown. Nothing has happened during the intervening Pygidium transverse to subsemicircular, with years to alter that view. convex axis standing above pleural areas; axis Protopliomerops Kobayashi, 1934 of four rings and lerminus; each ring of Type species (by original designation): Pro- uniform length, fourth only slightly shorter topliomerops seisonensts Kobayashi, 1934 from than first; terminus almost twice as long as a the late Tremadoc Protopliomerops Zone at ring, considerably narrower than fourth ring, Saisho-ri, South Korea (Tomkol Shale of reaching margin posteriorly, descending steeply Kobayashi, 1966). lo posterior; pleural area with well impressed pleural and interpleural furrows, tapering Remarks: This genus was diagnosed by posteriorly, with pleural area of fourth segment Kobayashi (1934) and extensively discussed by absent; pleural furrows beginning near anterior Ross (1951) with additions to the diagnosis. The of segment at axial furrow, running transverse- species described below adds only an ar- so fur- ly in two anterior segments then curving a little ticulated thorax to the generic concept to the posterior lo finish in line with the anterior ther discussion is unnecessary. part of the marginal spine, running transversely Protopliomerops hamaxitus sp. nov across narrow third pleura towards the anterior Plate 13, figures 1-14 pari of I he marginal spine; interpleural furrows

transverse for most of their course before turn- 1474 Cybelopsis '.p. ( orbett & Banks, pi. 2, figs 15, 16. 1980 IPHomeiina Staii ing slightly posteriorly abaxially and meeting subquadrata (Kobayashi); & 1 .nine, fig. 3, appendix 1. margin between marginal spines; four pairs ol Etymology: From Greek huma.xitos evenly spaced marginal spines present; first and meaning highway; referring second pairs of marginal spines tapering evenly to type locality on a highway. from base but quite long (about as long as pygidium), circular lo slightly flattened in sec- Material: Holotype UTGD122585, paratvpes tion; third marginal spine with parallel sides UTC.D95886, 95999, 96003, 96625, 121491, and through the part preserved and inferred lo be 122579-122587 all from NMVPL1602. considerably longer than others; fourth Numerous other specimens from each of the marginal spine shortest, almost exsagittal, localities indicated in the introduction were also widely separated from axial lerminus and hence available. from matching spine on other side; ornament Diagnosis: Member of Protopliomerops with on pygidium of line sparsely scattered axial furrows diverging very weakly forward; tubercles. lateral glabellar furrows slit-like, 3p reaching Remarks: The species laxobases are the axial furrow at anterolateral corner of glabella; different sized pygidial marginal spine and the occipital furrow with strong anterior curve fixigenal spine situated adaxially from the genal medially over the axis; occipital ring without I IKII I I RIM I I MHK OHM S ROM 1111 I OR1 MINI \ At I 1 25

node; palpebral lobe not markedly expanded, flattened in a plane at approximately 60° to the long extending back lo level of lp furrow; genal plane of the main body o( the hypostome; spines short; ornament over whole cephalon of border furrows well impressed running into tine pustules, cheek areas with numerous pits distinct median furrows very close lo posterior; between a network of ridges. Thorax of 12 posterior lobe short bul longer than posterior segments; pleural tips .spinose. curved slightly boulcr. isolated completely by median furrows; posteriorly. Pygidium with axis tapering shoulder only slightly expanded; entire surface strongly posteriorly, of five rings and triangular covered with line pustulose ornameni. terminus drawn out to reach posterior margin; Thorax o( 12 segments; axis shorl, highly five pairs of marginal spines with tips well convex with very shorl articulating half ring, apart; anterior border very short. with strong bulbous apodemes laterally in ar- furrow; pleurae will) very short Description: Small trilobite. tapering posterior- ticulating anterior pleural bands not evident on most ly throughout the axis and in the lateral spinose they aie concealed by the next margin. Cephalon semicircular, moderately specimens (as deep within the pleural fur- convex, proparian; glabella approximately 0.33 anterior segment row); pleural furrows well impressed, dividing of cephalic width, widest anteriorly, with

I shorl low aniciior pleural band from the broadly rounded anterior, straight sides, and he long high posterior pleural band thai occupies three pairs of lateral glabellar furrows; lp fur-

all l he exposed pari of l he pleura; row longest of three, angling backwards almost pleural extremities are long, hollow, free spines towards axis; 3p furrow most oblique, meeting that taper gradually and curve posteriorly From axial furrow at or in front of the anterolateral the articulating line (clearly evident on internal corner of the glabella; occipital furrow swing- moulds (PI. 10. fig. 10)); articulating lines con- ing strongly forward near adaxial end of furrow verging posteriorly, with narrow distinct lp, in an even curve across axis, deep, with doublure beneath. U-shaped cross-section; occipital ring with Pygidium semicircular, weakly convex; axis slightly oblique posterior margin laterally of live rings of equal length, becoming pro- becoming transverse medially, without node, narrower posteriorly and a terminus; elongate medially; anterior border short and gressive!) terminus triangular, longei than wide, reaching convex medially, slightly flatter and longer posterior margin, much narrower than lasl ax- lateral to glabella; anterior border furrow shorl ial ring, enclosed laterally by fifth pleurae, and slil-like medially, elongate lateral to the separated from fifth pleurae by very shallow glabella in front of the palpebral ridge; furrows; transaxial furrows deep, becoming palpebral ridge narrow but relatively long, con- shallower and shoilci posteriorly, weakly con- tinuing unchanged into the palpebral lobe; vex anteriorly; articulating half ring and palpebral lobe not greatly expanded, swung anterioi border extremely shorl and low, latter back strongly lo be almost exsagittal, almost ol uniform length; anterior pleural band visible reaching back to lp furrow; facial suture run- low in lirsl pleural furrow of some specimens; ning forward from palpebral lobe close to axial pleural furrows very deep, moie posterior ones furrow only a short distance to margin, running curving posteriorly, with fifth pair exsagittal Lo almost transversely behind eye but curving back converging; posterior pleural band dominating distally to meet the margin just in front of the pleural areas as high ridges extending beyond genal angle; interocular cheeks very narrow; margin as large spines; marginal spines posterior border becoming elongate near genal finishing with lips of successive spines well angle, drawnout at genal angle into short spine apaii and sharply pointed, in five pairs ol which that extends only slightly laterally but strongly second and third seem longest; all raised areas posteriorly. Fixigena triangular, with well- covered by pustulose ornament bul furrows impressed border furrow, convex border and smooth. high curved doublure. Hypostome with promi- The ornament, occipital furrow, lack nent convex median body occupying most of its Remarks: of occipital node, widely spaced lips of I he area; anterior wings wide, tapering laterally. P. A. JELL AND B. SI All

pygiclial marginal spines and longer palpebral tatus and this Tasmanian material. In fact there lobes distinguish P. hamaxitus from the type are no observable differences. Essential features species. Prolopliomerops granulatus and P. of the cranidium are the almost isolated lp punctatus both from Korea (Kobayashi, 1934, glabellar lobes, the almost transverse glabellar pi. 7, figs 2-5) may be distinguished by their furrows with 3p meeting the axial furrow pygidia having six pairs of marginal spines. The behind the anterolateral corner of the glabella, three species assigned to Prolopliomerops by the long palpebral lobe (or rather palpebro- Ross (1951) from Utah may be distinguished by ocular ridge), and short genal spine. These their expanded palpebral lobes and different features do not compare with any known combinations of other features in the pygidium. cranidia and certainly not with the short Prolopliomerops rossi Harrington & Leanza, palpebral lobe of Kobayshi's P. punctatus. 1957 may be distinguished by its glabellar However, his representation does show- shape, and the widely separated fifth pair of transverse glabellar furrows with 3p behind the pygidial marginal spines without the discrete anterolateral glabellar corner. These cranidia triangular terminus between them. Glabellar may prove to have the features of P. punctatus shape varies in the five illustrated internal when cranidia of that species are better known. moulds of cranidia to the same extent as in the Gordon Road collections so this may not be a distinguishing feature. In members of this fami- References ly morphology is so different depending on

whether internal moulds or external surfaces Angeijn, N. P., 1854. Palaeontologica Scandinavica. Part 2. Academiae Seientarium 21-92. are used that P. rossi may ultimately prove to Regiae Suecanae. Banks, VI. R. & Bckri: 1 r. C. F., 1980. A preliminary Or- be synonymous with P. hamaxiius. Features dovician hiosiratigraphv of Tasmania. J. geol. Soc. most distinctive of P. hamaxiius seem to be its Ami. 26: 363-375.

Barton, D. C, 1915. a revision of I he Cheirurinae, with lack of an occipital node, long palpebral lobes, miles on [heir evolution. Wash. Univ. Stud, scieni. five pairs of well spread pygidial marginal Ser. 3: 101-152. spines and almost no expression of anterior BERG, R. R. &. Ross. R. J., 1959. Trilobites from ihe Peerless and Manilou Formalions, Colorado. ./. pleural bands in pleural areas. Paleont. 33: 106-119. A complete morphogeny is not available but Bergeron, J., 1889. Etude geotogique du Massif ancten one juvenile pygidium plus posterior thorax sirue an sud du plateau central, these. Paris. 1-362. Bergeron, t, IS95. Notes paleontologiques. Butt. soc. (PI. fig. 13, 4) does give some insight into geol. France 23: 465-484. growth of that part of the cxoskeleton. Billings, t., 1859. Deseription of* some new species of irilobilcs from the lower and middle Silurian of Canada, Can. Naturalist 4: 367-383. Protopliomerops sp. cf. P. punctatus Billings, E., 1860. On some new species of fossils from the Kobayashi, 1934 limestone near Point Levi opposite Quebec. Can. Naturalist 5: 301-324. Plate figures 1-3; plate 12, figures 5-7 11, Broggir, \V. C. 1896. Uber die Verbreitung Euloma- Niobe Fauna (der Ceratopygenkalkfauna) in Europe. Material: Three cranidia (UTGD122562-122564) Nvt Magazin for Naturvidenskaberne 35: 16-24. < ai i away, C, 1877. On a new area of Upper Cambrian and three pygidia (UTGD 122574- 122576) all rocks in south Shropshire, wilh a description of a new from a single block of shale at NMVPL1602. Fauna, Quart. J. geol. Soc. land. 33: 652-671. Chang, W. T., 1949. Ordovician trilobites I'rom Kaiping,

Hebei and I he Qaidam Basin. Bull. Geol. Soc. China Remarks: The comparison of this material with 29: 110-125. Kobayashi's species is based almost exclusively Chugaeva. M. N. & Apollonov, M. K., 1982. The on the pygidium because the tiny fragment of a Cambrian-Ordovician boundary in the Batyrbaisai sec- tion, Malyi KARATAU Range, Kazakhstan, USSR. In cranidium assigned by Kobayashi, could scarce- The Cambrian-Ordovician boundary: sections, fossil ly be considered to provide an adequate basis distributions, and correlations. M. G. Bassell & W. T. for comparison. The six pairs of pygidial Dean, eds, National Museum of Wales, Geological spines, the way the pleural ribs are close Series, No. 3, Cardiff, 77-85. Cooper, R. A. & Stewart, I., 1979. The Tremadoc grap- together and the structure of the axis are all tolile sequence of Lancefleld, Victoria. Palaeontology significant features that are shared by P. punc- 22: 767-797. TREMADOC TRILOBITES FROM THE FLORENTINE VALLEY 27

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west Siberian Platform. Trudv Inst Geo/, i Geo/iz. 36: PLATE 1 1-196. Salter, J. W., 1866. A monograph of the British trilobites. Hyaricurus timsheaensis sp. nov. All from NMVPL1600. Palaeonlographical Society Monograph, London, pp. 129-176. Figure 1. Latex cast of damaged cranidium distorted by Sdzuy, K., 1955. Die Fauna der Leimitz-Schiefer compression in the longitudinal direction; (Tremadoc). Abh. senckenb. naturf. Gesell. 492: 1-74. showing wide palpebral lobe and deep lossulae, Sheng, S, F., 1934. Lower Ordovician trilobite fauna of UTGD 122500, x 2. Chekiang. Palaeont. Sinica, ser. B, 3(1). Shercold, J. H., 1975. Late Cambrian and Early Ordo- Figure 2. Internal mould ol two damaged cranidia lying vician trilobites from the Burke River Structural Belt, one on top of t he other with axes at right angles western Queensland, Australia. Bull. Bur. Miner. so thai distortion is clearly shown bv difference Resour. Geol. Geophys Aust. 153: 1-251. between ihe two, UTGD122501 and 122x02 Siait, B. & Laurie, J. R., 1980. Lilhostratigraphy and x2. biostraligraphy of the Florentine Valley Formation in Figure 3. Latex cast ol the Tim Shea area, south- west Tasmania. Pap. Proc. damaged cranidium showing R. Soc. Tasm. 114: 201-207. posterior expansion ol palpebral lobe, the coarse ornament and few Sun, Y. C, 1931. Ordovician trilobites of central and a terrace lines near the anterior margin, southern China. Palaeont. Sinica, ser. B, 7(1). UTGDI22503, x4. Thoral, M, 1935. Contribution a VEtude paleonlolo- Figure 4. Latex cast from only slight ly disarticulated, gique de I'Ordovicien inferieur de la Montague Noire et damaged holotype specimen including revision sommaire de la faune eambnenne de la Mon- cranidium, part tagne Noire. Montpellier, 1-362. of thorax, and pygidium, UTGD95867, * 2. Tjernvik, T. E., 1956. On the Early Ordovician of Sweden: stratigraphy and fauna. Geol. Inst. Univ. Uppsala 16: 107-284. Figure 5. Latex cast of pan ot cranidium (UTGD122504) Vogdes, and free cheek (UTGD122505) showing orna- A. W., 1925. Palaeozoic Crustacea, part 2 — a list ment completely of genera and subgenera of the Triiobita. Trans. San subdued by distortion in shale aftet burial, lateral Diego Soc. Nat. Hist. 4: 87-1 15. and compression of cheek border near anterior, >3. Walcott, C. D., 1914. Dikelocephalus and other genera Of the Dikeiocephalinae. Smithson. misc. Collns 57: 345-412. Figure 6. Latex cast from complete free cheek except for incomplete genal spine Walcott, C. D., 1925. Cambrian and Ozarkian trilobites. showing visual surface, Smithson. misc. Collns 75: 61-146. c.iccal network, terrace lines on border and distinct eye socle, Webby, B. D., Vandenberg, A. H. VL. Cooper, R. A.. UTGD122506, x6. Banks, M. R., Burrett, C. F., Hi ndereson. R. A., Figure 7. I ate\ cast from Clarkson, P. D., Hughes, C, Laurie, J. E., Siait. damaged external mould of p\gidium B., Thomson, M, R. A. & Webers, G., 1981. Oidmi- in posterolateral view showing cian System in Australia, New Zealand and Antarctica strongly divided axial terminus and high IUGS Publ. 6: 1-64. marginal band with well developed terrace lines, UTGDI22507, Whittington, H. B., 1950. A monograph of the British x3.5. trilobites of the Family Harpidae. Palaeontographical Society Monograph, London, 1-55. Figure 8. Latex cast of damaged pygidium (UTGD 122508) and cranidium Whittington, H. B., 1961. Middle Ordovician (UTGD 122509). x 3. Pliomeridae (Triiobita) from Nevada, New York, I igure 9. Latex cast of damaged Quebec, Newfoundland. J. Paleonl. 35: 911-922. pygidium in pos- terolateral view showing narrow doublure, Xia, 1978. Asaphopsis ovoideus sp. nov. In Sinian to Per- marginal terrace lines, and strong medial tuber- mian stratigraphy and palaeontologv of the eastern cle on anterior axial ring, UTGD122510, x5. Shanxi area. Hubei Geological Bureau, ed., Geoloey Press, Peking, p. 168, pi. 32, figs 13, 14. Figure 10. Latex cast of pygidium with ornament and Yin, Gong-Sheng & Li Shen-Chi, 1978. Class Triiobita. In furrows subdued bv tectonic distortion, Atlas of the palaeontology the southwestern of regions UTGD122511, x4. of China. Guizhou Stratigraphy and Palaeontoloev Work Team, ed., v. 1, Cambrian-Devonian, 385-594. Figure 11. Latex cast of pygidium showing axial tubercles, Zhou, Tan-Mei, Liu, 1-Jen, Mono Sung, & Sun, extent of pleural furrows, posteromedial Tzeng-Wa, 1977. Triiobita. in Atlas of the palaeon- marginal indentation, and extent of axis, tology of south central China. I. Early Palaeozoic UTGD122512, x4. volume. Hubei Institute of Geological Sciences, Hubei Geological Bureau, Kwantung Geological Bureau, Figure 12. Latex cast of damaged fixigena (UTGD1225I3) Honan Geological Bureau, Hunan Geological Bureau! and cranidium (UTGD1225I4), showing the Kwangsi Geological Bureau, eds. Geology Press tuberculate ornament, upturned Peking, 104-266. palpebral lobe, and anterior structure, x2.5. Zhou, Zhi-Yi & Zhang, Jin-Lin, 1978. Cambrian- Ordovieian boundary of the Tangshan area with Figure 13. Internal mould of distorted pygidium showing descriptions of the related trilobite fauna Acta furrows on pleural areas and divided axial ter- Palaeont. Sin. 17: 1-28. minus, UTGD122515, x5. TREMADOC TRILOB1TES FROM THE FLORENTINE VALLEY 29

Figure 14. Latex cast of damaged pygidium showing Figure 13. Latex cast of damaged cranidium from 5 Road marginal band in posterior oblique view, showing wide palpebral lobes and posterior UTGD96680, x3.5. cephalic limb, UTGD81049, x5.

with most of genal spine Figure 15. Internal mould of pvgidium (UTGD122516) Figure 14. Latex cast of librigena and librigena (UTGD122517) with external missing from NMVPL182, in lateral oblique mould of another librigena in upper right view, showing border furrow shallowing at rear (UTGD122518) x2. and high eye socle, UTGD98084, x4.

pygidium with PLATE 2 Figure 15. Latex cast of two cranidia and a a cranidium of Asaphopsoides florentinensis Hystricurus lewisi (Kobayashi, 1940). lying between the cranidia of this species, from NMVPL182, showing the different morpho- Figure 1. Latex cast of damaged cranidium from logies produced by the different orientation NMVPL182 showing flattened anterior border relative to the slatey cleavage — compression (exaggerating length of border) and wide has been in the direction up and down the page palpebral lobes, UTGD96055, x5. so that the upper cranidium is compressed laterally whereas lower one is compressed in Figure 2. Latex cast Of damaged flattened holotype sagittal line, also showing weak lp furrow, cranidium from limonite encrusted external UTGD122524, 122525, 122526 and 122527 mould (obliterating surface ornament), Z151, from top to bottom respectively, x 3. x6.

Figure 3. Latex cast of an incomplete cranidium from locality. Kobavashi's original material, the type " PLATE 3

Z995 ( = B1423), x4. Figures 1-7. Tanvbregma tasmaniensis sp. nov. All from NMVPL1600. Figure 4. Internal mould of damaged and distorted cranidium from the type locality of H. lewisi Figure 1. Latex cast of damaged librigena showing visual (holotvpe of Tasmanaspii longus Kobayashi, surface, anterior extent of doublure and den- 1 940).' Z 150. x4. ticles on adaxial margin of genal spine, UTGD122528, x4. Figure 5 Latex cast of small cranidium from NMVPL1601, showing lona preglabellar field Figure Internal mould of distorted cranidium, wide palpebral lobes, LTGD122519. - 4; and UTGD96674, x4 A, anterior oblique view; B, dorsal view.

3. Internal mould of holotype cranidium showing Figure 6. Latex cast of small cranidium from NM\ PI Figure long preglabellar length, palpebral lobes, lp 182, UTGD122520, x3. furrow, and course of facial suture, UTGD cranidium from Figure 7. Latex cast of small 95983, x3.5. NMVPL182 crushed down on right antero- palpebral lobe appears lateral corner so thai Figure 4. Latex east of librigena in ventral view showing its width is turned narrow because most of terrace lines on the doublure, ridge running appears directly down and preglabellar field down genal spine, and denticles on genal spine, and compressed short because it it depressed UTGD96676, x2. with border strongly upturned, UTGD 122521, x.3.5. Figure 5. Latex cast of incomplete librigena showing ex- tent of doublure forward of facial suture and Fiaure 8. Latex cast of cranidium from 5 Road, showing width of doublure, UTGD122529, x3. ornament, anterior course of facial suture, and

palpebral lobes, UTGD81067, • 3, Figure 6. Internal mould of librigena showing visual sur- face, course of facial suture, and mould of Figure 9. Internal mould of librigena from NMVPL182 ridge on underside of genal spine, UTGD showing coarse ornament and anterior extent 122530, x4. of doublure, UTODI22522, x3.5. cranidium showing small Figure 7. Internal mould of damaged Figure 10. Internal mould (A) and latex cast (B) of caecal network on preglabellar area, concave librigena from NMVPL183, in dorsal view, border, and posterior limb, UTGD122531, showing difference of ornament on inner and x2. outer surfaces of exoskeletons, terrace lines on the border and antetiot extension of border, UTGD122523, x5. sp. cf. robustus Ross, Figures 8 1 1, 12, 14. Hystricurus H. cranidium from 1951 Figure 11 Internal mould of a NMVPL1602, UIGDKI062, x3.5. Figure 8. Latex cast of pygidium from NMVPL1602 on from showing axial structure, extent of furrows 12. Latex cast of damaged librigena Figure pleurae, and occasional coarse tubercles on NMVPI.1602, in lateral oblique view showing axial rings and pleural ribs, UTGD95885, x6. visual surface and eye socle, UTGD96710, x 5. 30 P. A. JELL AND B. STMT

Figure II. Internal mould of pygidium from NMVPL Figure 9. Latex cast of cranidium showing long glabellar 1602 showing fine tubercles representing pits on furrows and marginal terrace lines on anterior the inner surface of exoskeleton, and the width border, UTGD96027, x3. of the doublure, UTGD122532, x3. Figure 10. Latex cast of incomplete pygidium showing curved marginal spine with terrace lines, ridges Figure 12. Latex cast of part of thorax and posterior of on pleural ribs position interpleural fur- cranidium from Adams Falls, UTGD96040, in of x4. rows, and marginal spine coming from third pygidial segment, UTGD9661 1, x 2. Figure 14. Internal mould of pygidium from Adams Falls, UTGD96620, x.3. figure II. Internal mould of pygidium distorted by shortening, showing apodemal pits in trans- axial furrows, anterior border furrow reaching Figures 9, 10, 13. Hystricurus lewisi Kobayashi, 1940 all from NMVPL182. margin in front of marginal spine, and doublure. UTGD96602, x3.

Figure 9. Latex cast of incomplete pygidium showing Figure 12. Asaphellus elheridgei sp. nov. Internal mould rim-like anteriorly tapering border, strong the of pygidium from Adams Falls showing terrace ridge at the genieulation, and steeply sloping lines on doublure, apodemal pits in transaxial outer part of pleura, UTGD122533, x4. furrows, and axial shape, UTGD96032, x 1.5.

Figure 10. Internal mould of pygidium showing doublure Figure 13. Nileidae gen. et sp. indet. Internal mould of and structure of axis, UTGD96049, x7. pygidium and five thoracic segments from Adams falls, UTGD96030, x2.5. (NOT Figure 13. Latex cast of slightly distorted pygidium show- DESCRIBED). ing pleural and interpleural furrows, and sharp genieulation, UTGD98080, x7. PLATE 5

PLATE 4 Chosenia udumsensis sp. nov. All from Adams Falls except

fig. I which is from NMVPL 1602. Figures 1-7. Hystricurus sp, cf. H. robuslus Ross, 1951.

Figure 1 . Latex cast of damaged holotype cranidium Figure 1 . Internal mould of damaged cranidium from showing long glabellar furrows and ridge cross- NMVPL1602 showing coarse ornament and ing axial furrow from anterolateral corner of long posterior limb, UTGU122534, x4. glabella, UTGD 122535, x2.

Figure 2. Internal mould of librigena from Adams Falls Figure 2. Latex cast of damaged librigena showing ter- showing the visual surface, doublure, and race lines, and course of border furrow, deflected genal spine, UTGD95913, x3. UTGD95945, x4.

figure 3. Internal mould (A) and latex cast from external Figure 3. Interna mould of damaged cranidium from mould (B) showing sparse tuberculate orna- Adams Falls showing extremely short ment, strong caecum from anterolateral corner preglabellar field, UTGD96626 of glabella, ten thoracic segments with wide pleural spines, and characteristic long anterior Figure 4. Internal mould of cranidium from Adams Falls border furrow on pygidium, UTGD96023, x3. showing palpebral lobe and posterior course of facial suture, UTGD96603, x3.5. Figure 4. Latex cast of damaged cranidium showing anterior marginal terrace lines, posterior Figure 5. Latex cast of librigena from NMVPL 1602 palpebral lobe, and tuberculate ornament on showing terrace lines on the border, eye socle glabellar lobes, UTGD96029, x4.5. and collapsed visual surface, UTGD981I4, x4. Figure 5. Latex cast of librigena showing structure of border, eye socle, terrace lines and genal spine, Figure 6. Latex cast of damaged cranidium from Adams UTGD96646, x5. Falls showing palpebral lobes, extremely short preglabellar field with median furrow, and Figure 6. Internal mould of damaged cranidium, posteriorly shallowing axial furrow, UTGD UTGD95927, x3. 96708, x3. Figure 7. Internal mould of damaged laterally com- pressed Figure 7. Latex cast of small librigena from Adams Falls pygidium showing long marginal, spine arising from second pygidial showing visual surface, eye socle, shallowing in segment, anterior border furrow border furrow just in front of genal angle, and running to margin forward of coarse ornament, UTGD122588, x7. marginal spine, and axis of six segments plus terminus, UTGD95942, x2.

Figures 8-11. Chosenia adamsensis sp. All from Figure 8. Latex cast of damaged, sagitally compressed Adams Falls. pygidium showing marginal spines with longitudinal terrace lines and issuing from Figure 8. Latex cast of damaged pygidium showing ter- third pygidial segment, seven axial rings plus race lines on marginal spines and axial struc- terminus, and interpleural furrows, UTGD ture, UTGD95175, x4. 96644, x3. ,

TREMADOC TRILOB1TES PROM THE FLORENTINE VALLEY

Figure 9. Internal mould of diagonally distorted Figure 12. Latex cast of pygidium and librigena, pygidium. UTGD96025, x2. UTGD95915 and 122539, respectively, xl.5.

Figure 10. Internal mould of sagi tally compressed PLATE 7 pygidium showing terrace lines on doublure, All from axis of seven rings and terminus, and marginal Megistaspis (Ekeraspis) euclides (Walcott, 1925). spine issuing from third segment, UTGD96637, NMVPL1601. x2. Figure 1. Inlernal mould of damaged cranidium, UTGD122540, x 1.5.

Figure 2. Latex cast of incomplete cranidium showing PLATE 6 course of the facial suture, palpebral lobe, and Asaphellus sp. cf, A. trinodosus Chang, 1949. All from low convexity of the cranidium, UTGD122541 NMVPL1602 x2.

Figure 1. Latex cast from incomplete external mould of figure 3. Latex cast of ventral side of librigena showing cranidium showing palpebral lobe and course long genal spine with ridge running down it, of facial suture, UTGD98111, x 2. wide doublure with terrace lines, and sagittal suture terminating doublure anteriorly, Figure 2. Latex cast from incomplete external mould of UTGD 122542, X 1. hypostome showing concentric terrace lines, median furrows, shape of the median body, Fiaure 4. Internal mould of cranidium, UTGD122543, and slight medial expansion of the posterior x 1. border, UTGD98137, x4.5.

I igure 5. Internal mould of incomplete librigena show- Figure 3. Latex cast from external mould of holotype ing eve socle, facial suture and wide anterior cranidium showing weakly defined glabella, doublure, UTGD98095, x2. palpebral lobes, facial suture barely diverging in front of palpebral lobes, and faint node Figure 6. Latex cast from incomplete external mould of posteromedially on glabella, UTGD96005, x 2. hypostome showing dorsally projecting an- terioi wiims, terrace lines, and deep median Figure 4. Latex cast of ventral surface of librigena show- fui row, UTGD122544, x2. ing terrace lines on wide convex doublure, UTGD95917, x 1. figure 7. Latex cast of damaged librigena showing eye socle. Hat border, and course of facial suture, Figure 5. Latex cast of incomplete librigena showing esc UTGD122545, xl.5. socle, short eenal spine, and line terrace lines near marginrUTGD95895, x2. figure 8. Latex cast form incomplete external mould of cranidium showing extent of glabella, anterior Figure 6. Latex casi of damaged cranidium showing pan of facial suture and its most posterior weak axial furrow, and palpebral lobes, part, UTGD 122546, x 2. UTGD96(X)2, x3 (thoracic segmenl of some other trilobitc impressed through the crani- Figure 9. Internal mould of small pygidium showing dium just forward of palpebral lobes). long posterior spine, UTGD122547, x2.

Figure 7. Latex cast of damaged librigena showing Figure 10. Latex cast of posterior part of hypostome anterior termination of doublure in sagittal showing terrace lines on the shoulder and shorl suture, eye socle, and marginal terrace lines, posterior lobe of median body, UTGD122548, UTGD98M7, x2. X4.

showing wide east pygidium showing axial and Figure 8. Internal mould of pygidium Figure 1 1. Latex of large doublure, low convexity and terrace lines on pleural structure, UTGD95994, x I. the doublure (on right), UTGDI22536, x 1.5. Figure 12. Latex cast of damaged hypostome, UTGD Fissure 9. Inlernal mould of damaged cranidium showing 122549, x3. axial furrow, palpebral lobes, and posterior course of facial suture, UTGD122537, x 1.5. figure 13. Lalex cast of sagitally compressed pygidium showing shorter posterior spine, UTGD98102, part of Figure 10. Latex cast of right posterolateral x3. hypostome showing deep median furrow, ter- race lines on the border with narrow upturned Figure 14. Latex cast o\ small distorted pygidium, margin and shorl posterior margin, UTGD UTGD122550, x3. 122538, x2. Figure 15. Internal mould of laterally compressed axial Figure 11. Internal mould of pygidium showing pygidium plus posterior live thoracic segments structure including transverse apodemes, showing pygidial doublure wilh terrace lines, pleural and interpleural furrows and wide and style of thoracic segment, UTGD122551, doublure with terrace lines, UTOD95877, x2. x2. y .

32 P. A. JELL AND B. SIAII

PI. AIL 8 Figure 7. Internal mould of cranidium showing posterolateral limbs, and fossulae, UTGD Dikelokephalina aslatica Kobayashi, 19.14. All from NMVI'1,1600. 122558, x2.5.

Figure 8. Latex cast Of right pleura of thoracic segment Figure 1. Latex cast of small fragment of a librigena showing ornament, facet, and pointed lip, probably referable lo this species showing, low UTGD122559, x3. eye socle and ornament of subtle terrace lines on genal field, UTGDI22552, x2. figure y. Latex cast of damaged sagilally compressed cranidium showing glabellar furrows, terrace igure 2. Internal mould of damaged laterally Com- lines on anterior border, palpebral lobes, and pressed pygidium showing axial structure and occipital node, x5. posterior spines, UTGD95981, x3. UTGD98075,

figure 10. Latex cast ol damaged cranidium diagonally figure 3. Internal mould of pygidium, UTGD95979, x3. distorted, UTGD122560, x3.

Figure 1 1 Internal mould oi damaged cranidium, figure 4 Latex casts from internal oi ventral (A) and ex- LTTGD80999, x3, terna] (B) moulds of damaged pygidium show- ing subtle terrace lines on border region, width PI.AII 10 of doublure and its terrace lines, posterior notch in inner edge of doublure and posterior Asaphopsoides florentinensis (Etheridge, 1905). spines, UTGD96689, x2.5. Figure I. Internal mould ol laterally compressed Figure 5. Internal mould of damaged pygidium, holotvpc pygidium from near 'the Gap' in the UTGD95982, x3. Florentine Valley AMI-y232, x2.

Figure 6. Latex cast of damaged cianidiutn showing Figure 2. Internal mould of incomplete librigena from palpebral lobe, glabella) furrows and fine Adams falls showing broad genal spine and lubciTiilalc ornament, UTGD95980, * 3. wide doublure, UTGD96022, X4,

Figure 7. Internal mould of cianidiutn showing Figure 3. Latex cast of joined librigenae and anterior palpebral lobes, glabella! fin tows, occipital border of cianidiutn from 5 Road showing node and preglabcllai structure, LTGD122553, facial suture, genal spines and border furrow, <3. (Cranidium of Tanybregma tasmaniensii UTGD8100I, - 1.5. sp. nov. in upper left UTGD1 22554). Figure 4. Internal mould of laterally compressed Figure K. Internal mould of damaged cranidium, pygidium from Adams falls showing wide UTGD95978, > 3. doublure with terrace lines and pleural and in- terpleural furrows, UTGD96036, x3.

Figure 5. Latex cast (A) and internal mould (B) of PFA'IL pydigium and nine thoracic segments from' NMVPLI82 showing increasing curvature of Asaphopsoides florentinensis (Etheridge, 1905). All from pleura) spines posteriorly, UTGD96652, x3. NMVPI.I82 except Figures 5, 6, 8, I 1 which come from 5 Road. Figure 6. 1 ate\ cast of ventral side ol librigena from 5 Road showing sagittal suture terminating Figure 1. Internal mould oi juvenile cranidium doublure anteriorly, wide doublure and course UTGDI22555, x7. of facial suture, UTGD96650, x2.

Figure 2. Internal of mould juvenile cranidium largei I igure 7. Internal mould of damaged pygidium from lhan previous one, QTGD98053, x5. NMVPL182 showing axial structure and broadly excavated margin posteromedially be- Figure 3. Internal mould of damaged hyposlomc tween marginal spines, UTGD98060, x4. UTGDI22556, X4. figure 8. Internal mould of laterally compressed figure 4. Latex cast from incomplete external mould of pygidium from Adams Falls showing terrace cranidium showing line terrace lines on lines on doublure and posterior marginal anterior border, UTGD81086, - 2.5. spines, UTGD80995, x3. figure 5. Latex cast hyposlomc of showing ornament, Figure y. Latex cast of pygidium from NMVPL182, median furrow, pits in posterior border fur- : axial row, and short posterior border, UTGD81019 122561, x2.5. x6. Figure 10. Internal mould of damaged pygidium from figure 6. latex cast of incomplete cranidium and Adams Falls showing width of doublure with librigena, UTGD80990 and 122557 respec- terrace lines and posterior marginal spines, tively, x3. UTGD96038, x2.5. I VAI 1 J3 1 REMADOC I Kll Oltl IPS FROM Hi: 11 ORPN1INP EY

12 PI All II PI ATE

Figures 1-4, Pilekiidae gen. el sp, nov. From NMVPI 1601. Figures 1-3. Protopliomerops sp. cf. P. punctatus

kohayashi, 1934. All from NMVPL.I602. in anterioi Figure I. Latex casi of damaged cranidium (A), anterolateral oblique (B), and dorsal ((') 1 external mould of Figure 1. atex cast From incomplete views, U K, 1)122570, <3, 3 ami 5, icspcc - 6. cranidium, UTGD122562, lively.

2. Internal mould of cranidium and anterioi Figure Figure 2. Latex cast of damaged cranidium, UTGD thoracic segments of enrolled individual show- 122571, > 5. ing transverse glabella! furrows, UTGD 122561, ,8. showing pleural and in- Figure 3. 1 atex casi of pygidium terpleural furrows and marginal spines, 3. Internal mould of two cranidia showing Figure U rGD122572, - 6. glabcllai transverse (lowei ) and oblique (upper) furrows, UTGD122564 and 122565. x5. in dorsal (A) and left Figure 4 I atex casi of pygidium 7. lateral oblique (B) views, UTGD122573, •

4-14. lauriei sp. nov. All from Figures Scotoharpes Figures 5-7. Protopliomerops sp. cf, I', punctatus NMVPI 16(12. Kohayashi, 1934. From NMVPI 1602.

showing si\ marginal Figure 5 1 atex cast of pygidium cranidium, 1 Figure 4. internal mould ol damaged spines on lefl side, 1 K ,1)122574. « 10.

UTGD95922, • 9. casi showing six marginal I igure 6 I atex of pygidium ol Figure 5. Latex east from incomplete external mould spines on right side, UTGD122575, 6. cranidium showing glabella! furrows, occipital node, eves, and eye ridges, UTGD121496, Figure 7 Latex cast of pygidium showing six marginal x II. (Broken off just oulside girder). spines on bolh sides, UTGD122576, - 8.

Figure 6. Latex cast of ventral surface of incomplete cranidium showing exteni ol girder, projecting Figures 8-12. Pitekiasp. nov. All from NMVPI 1600. rim ai margin, inner extent ol doublure anil

• 6, caecal network, U rGD98116, Figure 8. Internal mould ol sagittally compressed ciaiuditiin showing prominent Ip lobes and ol Figure 7. Latex cast from damaged external mould strong genal spine (detailed iii (Hi where iis ex- 2.5. cranidium with three thoracic segments a) ternal mould is visible), UTGD122577, x tached showing spine on tip of prolongation, 4. eyes and eaecai network, UTGD122566, - incomplete and distorted I igure 9. I atex cast ol cranidium showing pitted ornamem of cheek showing Figure x Internal mould of damaged cranidium and nature of palpebral lobe, UTGD96664, extent of girder, UTGD122567, , 10. 2.

damaged external mould ot cranidium showing or- Figure 9. l.alcv east from Figure 10. I atex cast ol damaged 6. hololypc specimen, UTGD121586, - naiiieii! and glabella! lunows, UTGD122578,

1 mould ol Figure 10. Latex casi from damaged external oblique view showing small cranidium m anterolateral Figure 11. Internal mould ol damaged cranidium showing marginal rim and eye, UTGD12256K, genal spine, glabella and ornament, UTGD -7. 95987, x2.

external mould ol pygidium Figure 11. Latex casi from damaged Figure 12. Internal mould of damaged holotype small cranidium showing spine on tip ol pro- showing lour marginal spines of different sizes,

.- 10. and ornament, Ui(il) longation, 1 rGD96007, interpleural furrows, 95989, x4. cast of dorsal (A) and ventral (B) sur- I igure 12. Latex caecal faces ol damaged cranidium showing PI All. 13 and and girder, l FGD122569, /5 network Protopliomerops hamaxitus sp. nov. All from / 6 respectively. NMVPI. 1602. pygidium and posterior Figure 13. Internal mould ol showing genal spines, I casi of cranidium showing tapering axis, nai Figure l. atex thoracic segment UTGD95999, /8. row bolder and smoolh pleural areas, UTGD96010, X9. showing live pair, ol Figure 2. Latex casi ol pygidium well separated marginal spines and pustulose mould ol a cranidium, UTGD96008, Figure 14. Internal ornament, UTGD95886, x 10. x8. 34 P. A. JELL AND B. STAIT

Figure 3. Latex cast of hypostome showing anterior Figure 9. Latex cast of damaged complete specimen wings and pustulose ornament, UTGD96003, showing 13 segments, UTGD96625, xlO. x20. Figure 10. Internal mould of damaged individual showing Figure 4. Latex cast of rear of thorax and pygidium of position of hypostome, free pleural spines and juvenile individual, UTGD122579, x 12. strong thoracic apodemes in articulating furrows, UTGD122583, x9. Figure 5. Latex cast of sagittally compressed cranidium showing glabellar furrows, palpebral lobe, and Figure 11. Latex cast of two cranidia, UTGD95884 (up- punctate ornament on cheek, UTGD121491, per) and 122584 (lower), x6. x8. Figure 12. Latex cast of damaged holotype cranidium showing ornament, glabellar furrows, lp join- Figure 6. Latex cast of damaged cranidium with ing occipital furrow, and short anterior border, librigena in place, UTGD 122580, x 11. UTGD122585, x9.

Figure 7. Latex cast of damaged cranidium and thorax, Figure 13. Latex cast of pygidium with large quadrate UTGD122581, x8. axial terminus, UTGD122586, x8.

Figure 8. Latex cast of hypostome showing ornament Figure 14. Latex cast of damaged cranidium and thorax, and faint median furrow, UTGD122582, x8. UTGD122587, x6. MEM. MUS. VICT. 46 PLATE 1 jf~7^\

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