PROC. R. SOC. VICT. vol. 96, no. 4, 173-186, Decemb er 1984

NEW PLACODERM FISHES FROM THE EARLY BUCHAN GROUP, EASTERN VICTORIA

By J ohn A. L ong

Department of G eology, Australian National Universi ty, P.O . Box 4, Canberra, A.C .T. 2601

A bstract : Three new placoderms are described from the McLarty Member of the Murrindal Limestone (Early Devonian, Buchan Group). M urrindalaspis wallacei gen. el sp. nov. is a palae- acanthaspidoid characterized by having a high m edia n dorsal crest and lacking a m edian ventral keel. M. bairdi sp. nov. differs from the type species in having a low median dorsal crest and a median ventral groove. Taem asosteus m aclarliensis sp. nov. differs from the type species T. novaustrocam bricus W hite in the shape of the posterior region of the nuchal plate, the presence of canals between the infranuch al pits and the posterior face o f the nuchal plate, th e shape of the paranuchal plate, and the developm en t of the apronic lam ina of the anterior lateral plate. The placoderm s, A renipiscis westoUi Young, Errolosleus cf. E. goodradigbeensis Young, W ijdeaspis warrooensis Young, are recorded from the Buchan Group indicati ng close sim ilarity to the ichthyofauna of the contem poraneous M urrumbidgee Group, New Sout h W ales.

Few fossil fishes have been studied from the Early been described from the Murrumbidgee and Mulga Devonian Buchan Group. M cCoy (1876) described some Downs Groups in New South Wales and the Cravens placoderm plates from this region as Asterolepis ornata Peak Beds in Queensland, with numerous sites yielding var. australis, which Chapman (1916) queried when m icrovertebrate assemblages (Long 1982, 1983b, Turn er presenting a description of a placoderm skull from et at. 1981, Long & Turner 1984). Buchan. Chapman identified this specimen as a phly- Specimens are housed in the following institutions: ctaenioid, Phlyctaenaspis confertituberculatus, but Hills CPC, Commonwealth Palaeontological Collections, (1936b) assigned the skull to . Stensio (1945) Bureau of Mineral Resources, Canberra; MUGD, recognized differences between the parasphenoid of Geology Department, M elbourne University; and NMV, Coccosteus and the Buchan specimen and erected M useum of Victoria, M elbourne. for the latter. Additional material of Buchanosteus has since been found from the M urrum­ SYSTEMATIC PALAEONTOLOGY bidgee G roup, New South W ales, making this genus on e Subclass P lacodermi M cCoy 1848 of the best known Early Devonian euarthrodires (W hite Superorder P etalichthyomorpha Miles & Young 1977 1952, W hite & Toombs 1972, Young 1979). The only Order P etalichthyida Jaekel 1911 other fish described from Buchan is a mandible of the dipnoan Dipnorhynchus sussmilchi (Hills 1936a, Thom ­ W ijdeaspis warrooensis Young 1978 son & Campbell 1971). This paper describes placoder m Fig. 4C ' fish material recovered from the Buchan Group durin g M aterial : A piece of trunk shield com prising the right Monash University third year geology field mapping spinal plate and a small sliver of the anterior lateral trips as well as some found by geology honours stud ents plate. NMVP159825, collected Dr. R . E. Fordyce, from both M elbourne and M onash Universities (Long February, 1981. 1983 b). O ccurrence : The uppermost division of the M cLarty The material was prepared using acetic acid with Member of the Murrindal Limestone, immediately dilute polyvinylbuterol to strengthen the exposed b one. northeast of Rocky Camp Quarry, north of Buchan. All specimens were found in the uppermost McLarty M ember or ihe lowermost Rocky Camp Member of the R emarks : The specimen is identified as belonging to M urrindal Limestone, with the richest concentration of Wijdeaspis because the spinal shows a relatively high occurring near the contact of the M cLar ty num ber of ornam ental ridges (9-10) which are form ed of and Rocky Camp M embers on the eastern face of Rocky closely packed tubercles arranged in rows. On this basis Camp Hill (Fig. 1). In addition to the macrovertebr ate Young (1978, p. 112) distinguished Wijdeaspis spinal remains rich concentrations of microvertebrate foss ils plates from those of Lunaspis species. The Buchan were recovered from the residues during preparation , specimen is almost identical with that of Wijdeaspis and these have been forwarded to Dr. S. Turner warrooensis figured by Young (1978, figs 2E, 8B). (Queensland Museum) for detailed study. Amongst these are several types of acanthodian and elasm obr anch Order R henanida Broili 1930 scales similar to forms described from the M urrum­ Suborder P alaeacanthaspidoidei Miles & Young 1977 bidgee G roup by Giffin (1980). Recently a jaw of a new Family W eeja sper a spida e W hite 1978 ischnacanthid acanthodian was found in residues fro m D ia g nosis : Palaeacanthaspidoids having a well the Rocky Camp Member (under current study by the developed median dorsal crest on the median dorsal author). Lower Devonian macrovertebrates have also plate, which has a posterior face with a smooth med ial

173 174 JOHN A. LONG

BUCHAN D ia g nosis : A weejasperaspid of m oderate size having a median dorsal plate with a sm ooth ventral surface w hich may have a median ventral groove developed; dermal ornam entation of short ridges, approxim ately one-th ird as long as broad, on the dorsal surfaces with pointed stellate tubercles densely concentrated near the an terior and posterior margins; median dorsal crest develope d; a short dorsal transverse sensory line canal situated at the anterior base of the median dorsal crest; the poste rior face of the median dorsal crest with a smooth media n prominence throughout.

T y pe S pec ies : Murrindalaspis wallacei sp. nov.

R emarks : This palaeacanthaspid is similar to Wee­ jasperaspis gavini W hite (1978) but differs in the absence of the median ventral keel on the median dorsal pla te. Palaeacanthaspis Stensio 1944 also possesses a median dorsal crest but differs from both Murrindalaspis and Weejasperaspis in possessing a large nutritive foramen for the crest on the ventral surface of the median dorsal plate, and by its simple tubercular ornam entation. Of the remaining described palaeacanthaspids none has a well developed median crest; where the median dorsa l plate is unknown (Brindabellaspis Y oung 1980, Romun- dina Orvig 1975, Kimaspis Mark-Kurik 1973a, Kolymaspis in Denison 1978) Murrindalaspis is dis­ tinguished by the characteristic dermal ornam entati on.

M urrindalaspis wallacei sp. nov. Figs 2A, D, E, G, 3, 8C, D

E tymology : After Mr. M. Wallace, Dept. Geology, University of Tasmania, who discovered several fish es from the Buchan area in 1982, including the type specimen of Murrindalaspis gen. nov., and kindly allowed me to study the material.

D ia g nosis : A member of Murrindalaspis with a median dorsal plate having a high median dorsal crest whic h is strongly curved posteriorly and tapers narrowly at its apex. Ventral surface of median dorsal plate smooth , Fig. 1 —Locality map of placoderm fossils collected in the and there are paired prominences developed at the Buchan region. G eology from Teichert & Talent (1958 ). posterior end of the ventral surface near the base of the crest. Ratio of median dorsal crest height/plate le ngth prominence. M edian dorsal plate with a B /L index ap­ approxim ately 64. proximately 80. Coarse ornamentation consisting of H olotype : M UGD6066 (Figs 2A, D, E , G, 3), an almost short ridges and pointed tubercles each with well d efined complete median dorsal plate from the top of the grooves. M cLarty Member of the M urrindal Limestone from the

R emarks : W hite’s diagnosis (1978) has been m odified to vicinity of Rocky Camp Quarry, north of Buchan incorporate features of the new genus from Buchan. (Fig. 1).

Weejasperaspis White 1978 and Murrindalaspis gen. D escr ipt ion : The holotype is almost complete, missing nov. are similar in the proportions of the m edian d orsal only the top of the crest and a small part of the left plate, in their median dorsal crests and in the mor ­ anterolateral corner. It bears a high, slender median phology of the derm al ornam entation; they differ ch iefly dorsal crest (cr.d) which starts approximately 28% of in the well-developed median ventral ridge on Wee­ the plate length from the anterior margin, and exte nds jasperaspis only, and in the size of tubercles of the backwards beyond the level of the posterior margin (Fig. external ornam ent. 3). In profile the crest is strongly curved, being propor­ tionately much narrower than the broad crest of Wee­ M urrindalaspis gen. nov. jasperaspis (Fig. 8). The anterior m argin of the plate has

E tymology : A fter the settlement of M urrindal, north of a short median convexity and lateral to this region the Buchan. anterior margin extends forward at an angle of abou t NEW PLACODERM FISHES

Fig. 2 —M urrindalaspis gen. nov., Emsian, Buchan. A , D, E, G, M . wallacei sp. nov., M UGD6066. H olotype m edian dorsal plate in A , ventral, D , post erior, E, right lateral and G, dorsal views, x l. B, C, F, H . M . bairdi sp. nov., NM VP59892. H olotype median dorsal plate in B, posterior, C, ventral, and F, right lateral views. H , detail of derm al ornam entat ion. B, x2; C, F, x l; H, x4. All specimens whitened with am m onium chloride. 176 JOHN A. LONG

40° to the lateral margin of the plate. There is a narrow D ia g nosis : A Murrindalaspis having a median dorsal overlap platform (ant.oa) along the extent of the plate which bears a low median dorsal crest. The ve ntral anterior margin. In dorsal view the plate has constant surface of the m edian dorsal plate has a well defin ed me­ breadth in its anterior half and tapers posteriorly dian ventral groove in the posterior half of the plate.

towards the posterior processes (ppr). The posterol ateral H olotype : An almost complete median dorsal plate, margin is straight, without the irregular notches s een on NMVP159893 from the base of the Rocky Camp Mem­ Weejasperaspis. There is a short transverse sensory line ber of the M urrindal Limestone, on the southeastern canal (dg) situated just anterior to the base of th e crest face of Rocky Camp quarry hill, north of Buchan and extending for a short distance laterally (Fig. 3D). (Fig. 1). The ventral surface of the plate is sm ooth with slightly R emarks : The two species of Murrindalaspis are known striated lateral margins where there is overlap with the only from median dorsal plates, yet as they both be ar anterior and presumably posterior dorsolateral plates ■ the same distinctive type of dermal ornam entation it is (oa.A D L). In the midline of the ventral surface the re is a assumed that they are congeneric. The differences seen concentration of small vascular pores (vas). Two la rger in the two species are not intraspecifically variab le foramina occur at the anterior end, below the position characters. In the antiarch Bothriolepis there are in­ of the transverse dorsal sensory canal, probably fo r in­ terspecific variations in the heights of median dor sal nervation of this sensory line. Posteriorly a media n pro­ crests and in the presence or absence of median ven tral cess (mpr) is developed, behind which are paired pr o- grooves (Miles 1968, Long 1983a). It is unfortunate that truberances (ppr) marking the base of the crest. In palaeacanthaspidoids are too rare as fossils to tes t the lateral view, these paired processes extend behind the or­ variability of the m edian dorsal plate m orphology w ithin nam ented external surface. W hite (1978, p. 159) noted and between species. The two median dorsal plates o f the presence of a process on the posterior face of the me­ Murrindalaspis are of about the same size which in­ dian dorsal of Weejasperaspis suggesting an articulation dicates that the differences seen between the two f orms for either a posterior median dorsal plate or body scute. are not attributable to growth changes. As the two As posterior median dorsal plates are only known in species occur in different lithofacies, M. bairdi in clean antiarchs, and body scutes tend to lie flat on the dorsal biosparite and M. wallacei in interlayered micritic ridge of the trunk it is more probable that this re gion packstones and mudstones, it is possible that the was an attachment area for a dorsal fin support. Th e differences in crest height could relate to the deg ree of posterior margin of the median dorsal spines of som e turbulence or current activity which predom inated in the ptyctodontids are grooved for attachm ent of the dor sal differing palaeoenvironm ents. fin support in a similar fashion (e.g. Rhamphodopsis D escr ipt ion : The holotype median dorsal plate is miss­ Miles 1967). In posterior view (Fig. 3B) the base o f the ing the anterior margin and left anterolateral corn er. median dorsal crest of M. wallacei shows a smooth me­ A lthough the left side of the crest is slightly dam aged the dian vertical thickening (mth) flanked on each side by full extent of the crest is shown on the right side of its well defined grooves, which deepen towards the base of dorsal margin. the crest. A short distance above the paired proces ses The plate (Fig. 2F) has a slender, broad median dor ­ there is a central foram en (for). As the plate was broken sal crest which runs along the entire preserved len gth of in two halves when collected it can be noted that there is the plate. The dorsal margin is gently curved with the a large canal inside the plate running along the ba se of crest height being approximately 51% of the overall the crest. height of the plate. The ratio of crest height to p late The ornamentation of Murrindalaspis (Fig. 2H), is length (as preserved) is 31. The form of the plate in dor­ quite distinctive as is this feature on many palaea can- sal view is the sam e as for M . wallacei (com pare Fig. 2A, thaspids. In the development of small ridges and C). The posterior face of the plate has a short med ian tubercles with distinctive ridges it is superficially sim ilar thickening which is bordered by a narrow ridge (Fig . to Weejasperaspis. It differs from this genus in that the 2B). The median thickening extends ventrally to mee t ridges are shorter (average approximately one-third as the lateral sides of the ventral median groove. The ven­ long as broad) and predom inate on the dorsal surfac e of tral aspect (Fig. 2C) shows this groove extending f or the plate with high, pointed stellate tubercles in dense 40% of the plate length from its posterior extent. concentrations at the anterior and posterior margin s. Anterior to the median ventral groove are numerous The crest has closely packed tubercles which grade into vascular foramina, as on the ventral surface of M. short, small ridges on its flanks. All ridges of or nament wallacei (Fig. 2A). The dermal ornamentation of M. on the plate have a rostrocaudal alignment, althoug h on bairdi is slightly coarser than that of M. wallacei just the lower part of the crest these form an angled pa ttern lateral to the base of the crest, and on the latera l sides of pointed towards the anterior end of the base of the crest. the crest (Fig. 2E, F) but is otherwise virtually in­ distinguishable on the two species. M urrindalaspis bairdi sp. nov. Fig. 2B, C, F, H

E tymology : After Mr. Robert Baird, Earth Sciences Order E uarthrodira Gross 1932 Dept., Monash University, who found the holotype Suborder P hlyctaenioidei Miles 1973 specimen in July, 1983. Infraorder B rachythoraci Gross 1932 NEW PLACODERM FISHES

Fig. 3 — M urrindalaspis wallacei gen. et sp. nov., Em sian, Buchan. H olotype median dorsal plate in A, right lateral, C, dorsal, and D, ventral views. B, detail of posterior face of m edian dorsal crest. M U GD 6066. ant.oa, anterior overlap surface; oa.A D L, ove rlap area for anterior and possibly posterior dor­ solateral plates; cr.d, median dorsal crest; dg, do rsal transverse sensory-line groove; for, posterior foram en of crest; mpr, m edian ventral process; m th, m edian thickening; ppr, paired posterior processes at base of crest; vas, vascular foram ina. 178 JOHN A. LONG

R emarks : These taxa were defined by Young (1979, p. rounded posterior margin. The overlap area for the me­ 344, 345) and Long (in press) has amended this defini­ dian dorsal plate extends for just under half of th e plate tion of the Euarthrodira to include phyllolepids. T he length with the ventral overlap area for the anterior following section records taxa from the Buchan Grou p lateral plate extending for 80% of plate length. Th e ex­ not previously reported, except for Buchanosteus con­ ternal ornamented area of the plate is broadest an­ fertituberculatus (Hills 1936b, White 1952, Young teriorly, then narrows before becoming broader at the 1979). posterior margin. The articular condyle is a short, rounded process as in other primitive ds. Arenipiscis westolli Young 1981b Fig. 4F Taem asosteus W hite 1952

M aterial : An almost complete nuchal plate, D ia g nosis : As in W hite, 1978, p. 184. NMVP159885, collected by Mr. Ken Simpson, 1975 T y pe S pec ies : Taemasosteus novaustrocambricus W hite from a road cutting near M urrindal, north of Buchan . 1952. Although the stratigraphic horizon was not indicate d on the label, the lithology suggests that the specimen came R emarks : W hite (1952) established this genus upon a from the thinly bedded, fossiliferous M cLarty M embe r single left paranuchal plate and recently redescrib ed the of the M urrindal Limestone. Other fish fragments ha ve taxon from over eighty plates (W hite 1978). Taemaso­ been found in this region on the road outcrop im­ steus novaustrocambricus is a common element in the mediately north of Henham Homestead. Taemas-W ee Jasper fauna, and has been reported at Buchan (Young 1979, p. 311) although details were n ot R emarks : The nuchal plate is referred to Arenipiscis given. This report was based on NMVP41829, a left westolli on the basis of relative proportions, the paranuchal attached to part of the nuchal (Fig. 6A) , col­ presence of a conspicuous median ventral depression lected by a M r. Goodwin from the Rocky Camp member and by the fine grained tubercular ornam entation. in the early 1970s and prepared by Dr. G. C. Young. In D escr ipt ion : The posterior m edian region of the plate is the recently collected material from Buchan not preserved, although the shape of the lateral Taemasosteus is common, although differences in pro­ posterior margins is apparent. Other features portion and morphology indicate that some of the characteristic of Arenipiscis seen on the Buchan material constitutes a new species, whereas other p lates specimen are the narrow anterior region of the plate, are indistinguishable from the type species. All th e numerous nutritive foramina along the median ventra l Buchan specimens resemble Taemasosteus novaustro­ depression, well defined infranuchal pits (only par tly cambricus in their large size, thickness, dermal or­ preserved) and the broad overlap areas for the nam entation and approxim ate shape, and are referred to paranuchal plates. The Buchan specimen has an the genus on these characters. estimated B/L index of 88 (the anterior margin and The following plates of Taemasosteus, collected near broadest lateral extremities are not complete). As the Buchan, are indistinguishable from the type species , T. New South W ales type m aterial does not include a co m­ novaustrocambricus: NM VP159889, an imperfect left plete nuchal plate, proportions can only be estimated central plate (Fig. 4E); NM VP159886, imperfect left from Young’s restoration (1981b, figs 5, 6), where the paranuchal plate (Fig. 6B); NMVP161865, an imperfec t nuchal is slightly broader than long. right interolateral plate (Fig. 7d); and NMVP159888 , a posterior region of the median dorsal plate (Fig. 7 B, C). Errolosteus cf. E. goodradigbeensis Young 1981b These may turn out to belong to the new species des ­ Fig. 4A cribed below but this cannot be shown unless articu lated

M aterial : Alm ost com plete anterior dorsolateral plate, material is found. For the present these specimens are NMVP159894 from the upper part of the McLarty referred to T. novaustrocambricus. M ember of the M urrindal Limestone in the vicinity o f Rocky Camp Quarry, north of Buchan. Taem asosteus m aclartiensis sp. nov. Figs 4B, D, 5, 6A, 7A, E, 8A R emarks : This genus is easily recognized by the characteristic dermal ornamentation of concentric E tymology : After the M cLarty M ember of the Rocky ridges bearing small tubercles. Young (1981b) descr ibed Camp quarry where most of the specimens were found.

the type species from an imperfect headshield, an D ia g nosis : A member of Taemasosteus having a nuchal anterior lateral plate and a posterior ventrolatera l plate. plate which is not strongly raised at the occipital end, The anterior dorsolateral plate from Buchan has a s hape and with short, deep grooves connecting the posteri or com patible with that of the dorsal margin of the an terior face of the nuchal plate to the large infranuchal p its. lateral of E. goodradigbeensis, and for this reason it is Posterior margin of the nuchal plate slightly conca ve, provisionally referred to this species until m ore m aterial much straighter than for T. novaustrocambricus. is recovered. Paranuchal plate with straight posterior margin for ming

D escr ipt io n : The anterior dorsolateral plate is higher an angle of 50° with the suture to the nuchal plate . than long, as in Buchanosteus and most phlyctaenioids Anterior lateral plate with 4 toothed ridges on the (Denison 1978). The plate has an overall H /L index of apronic lamina which is inturned at an angle of 65° to 153. The anterior margin of the plate is longer tha n the the lateral lam ina of the trunkshield. NEW PLACODERM FISHES

Fig. 4 —A , Errolosteus cf. E. goodradigbeensis Y oung. Right anterior dorsolateral plate in latera l view, N M VP159894, x 1. B, D, Taem asosteus m aclartiensis sp. nov., holotype nuchal plate in B, ventral, and D, posterior views, NM VP159887. B, x l; D, X 1.5.C , W ijdeaspis warooensis Y oung. Left spinal plate in ventral view, NM VP159825, X2. E, Taem asosteus cf. T. novaustrocam bricus, left central plate in dorsal view, NM VP 159889, x l. F, A renipiscis westolli Young, nuchal plate in ventral view, N M VP 159885, x2. All whitened with am m onium chloride. 180 JOHN A. LONG

novaustrocambricus but the posterior m argin is straight and the posterior profile of the plate is lower. W h ite (1978, p. 186) noted that in T. novaustrocambricus the occipital region of the nuchal plate is raised stro ngly, more so in larger plates. Examination of the Britis h M useum specimens confirmed that this is a feature o f all specimens, and as the occipital region of the nucha l is not strongly elevated in the two specimens from Buc han it is assumed to be a specific characteristic of T. novaustrocambricus. The middle part of the posterior margin of the nuchal in T. maclartiensis (Fig. 5) is only slightly concave, whereas in all specimens of T. novaustrocambricus this margin is strongly concave medially (bordering the posterior face, giving the whole of the posterior margin a W -shape seen in Fig. 8A, B). As in the type species the infranuchal pits (inp) a re also large and deep in T. maclartiensis, being stepped in NMVP159887 with the deepest excavation in the anterior half and the infranuchal ridge (inr) givin g way 1cm anteriorly to a median depression (med. dep). The posterolateral corner of each infranuchal pit has a clearly marked deep groove (can) leading to the ven - Fig. 5 — Taem asosteus m aclartiensis sp. nov., Em sian, Buchan. tromesial corner of the ventral muscle attachm ent r egion Holotype nuchal plate in ventral view, NM VP159887. can, (v. mus) on the posterior face of the plate. MUGD60 64 deep grooves between infranuchal pits and ventral m uscle area; is very worn in this region but still shows vestige s of the ep, epiolic prom inence; inp, infranuchal pit; inr, infranuchal canals. The epiotic prom inences (ep) are clearly se en im­ ridge; med. dep, median depression; mpr, median pro cess or mediately posterior to these canals in the holotype (Fig. supraoccipital spine; oalPN u, oa2PNu, overlap areas for 5). The supraoccipital spine (mpr) is a bifid struc ture paranuchal plate; p.m us, posterior muscle attachmen t area; vas.c, vascular canals; v.m us, ventral m uscle attac hm ent area. with smaller pointed protuberances (pr) flanking ea ch side close to the dorsal m argin. Below the supraocc ipital spine is a broad concave area, presumably for attac h­ M aterial : Holotype NM VP159887 (Figs 4B, D, 5), a ment of the medial division of the levator capituli large portion of the nuchal plate, showing all of the muscles. Lateral to the epiotic prominences is an e xten­ characteristic features; M UGD6064, an almost comple te sive, smooth region for other muscle attachment (v. nuchal plate, more worn than the holotype; mus), and dorsal to this field on the posterior fac e of the NMVP41829, almost complete left paranuchal plate plate is a posterior muscle attachment area (p. mus ). with part of left side of nuchal attached (Fig. 6A); W hite (1978) noted the presence of foramina for the NM VP 159891, com plete right anterior lateral plate (Fig. posterior cerebral veins around the supraoccipital spine 7A, E). on the nuchal plate of T. novaustrocambricus. In the O ccurrence : All specimens were collected from the holotype of T. maclartiensis there are numerous small vicinity of the Rocky Cam p quarry, on the eastern s lope pores in this region (vas. c), presumably for vascu lar of the hill, in the topmost section of the McLarty supply, but large conspicuous foram ina are not pres ent. Member and lowermost Rocky Camp M ember (Fig. 1). The dorsal smooth overlap flange for the extrascapu lar M ost of the material was collected by the author an d plates appears to be more extensive for the holotyp e of friends during 1980-1983. T. maclartiensis than for any of the figured specimens of R emarks : The material is believed to be conspecific T. novaustrocambricus, but such differences are difficult because all these plates show differences from the type to define as specific characters. As in the type sp ecies species, and were collected from the same stratigra phic there are two-tiered overlap areas for the paranuch al horizon. The new species is distinctive in the mor­ plates (oalPN u, oa2PNu). At the junction of the thin phology of the nuchal, paranuchal and anterior late ral anterior overlap lamina with the thicker posterior plates, and as there are two specimens of the nucha l overlap area on the holotype there is a semicircula r me­ plate which exhibit distinctive features com pared to T. dian thickening intermediate in height between the two novaustrocambricus of the same size, the differences levels (Fig. 8A, oaPNu). between the type species and T. maclartiensis sp. nov. The paranuchal plate is well preserved on are unlikely to be due to abnorm ality or changes du ring NM VP41829 (Fig. 6A), where it is articulated to par t of growth. the nuchal plate, missing only the posterom esial co rner.

D escr ipt ion : Nuchal plate. NMVP159887 shows the This specimen differs from the paranuchal plates of T. posterior half of the plate perfectly preserved whe reas novaustrocambricus in having a straight posterior M UGD6064 gives an overall estimation of proportions margin (pm) which forms an angle of 50° from the of the entire plate. Proportions are similar to T. suture with the nuchal plate. All the figured paran uchal NEW PLACODERM FISHES 181

Fig. 6— Taemasosteus paranuchal plates in dorsal view. A , T. m aclartiensis NM VP41829, Buchan. B-D, T. novauslrocam bricus. B, NM VP159886, Buchan. C, restoration of paranucha l plate by W hile (1978, fig. 77, reversed to m atch other plates figured her e). D, British M useum specimen P33712, Taem as, from W hite (1978, pi. 9C). Bar scale equals one centim et re. E x.oa, area overlain by extrascapular plates; g lp, glenoid process; m il, m ain lateral line canal groov e; Nu, nuchal plate; oalN u, oa2Nu, areas overlapped by nuchal plate; pm , posterior margin of paranuchal plate; PN u, paranuchal plale.

plates of T. novauslrocambricus have convex posterior E uarthrodira gen. indet. margins and make an angle close to 65°with the exte rnal

contact margin of the nuchal plate (W hite 1978, pi. 9A, M aterial ; NM VP159890, an almost complete left C, D; Fig. 6 B, C, D). The course of the main later al suborbital plate (Fig. 7F) from the base of the Roc ky line-canal (mil) is essentially as in the type spec ies. Camp Member, M urrindal Limestone, Buchan Group, The anterior lateral plate of T. maclartiensis (Fig. on the eastern slope of Rocky Camp Hill (Fig. 1).

7A, E) differs from that of the type species in hav ing a R emarks ; This large specimen bears very little dermal smaller num ber of toothed ridges on the apronic lam ina. ornam ent which is concentrated close to the centre of In the figured specimens of T. novaustrocambricus radiation of the plate, and these are of low rounde d (W hite 1978) and in CPC25337 there are 7-10 toothed tubercles.There is no orbital notch present, but th ere is a ridges on the apron, whereas the Buchan specimen well developed linguiform process for attachm ent of the shows only 4. As the best preserved specimen of this autopalatine. This feature is characteristic of hig her plate of T. novaustrocambricus (W hite 1978, pi. 12A) is brachythoracids (Dennis & Miles 1983, Young 1981b), approximately the same size as the Buchan specimen being absent on forms such as (M iles 1971), these differences cannot be attributed to growth ch anges Buchanosteus and Goodradigbeeon (Young 1979, W hite and are here regarded as specific features. Another 1978). The figured suborbital plates of Taemasosteus difference between the species is that the apronic lamina novaustrocambricus (W hite 1978) differ in having an or­ is strongly inturned on T. maclartiensis, forming an bital notch, but are otherwise similar to this spec imen angle of 65° to the lateral lamina of the trunkshie ld, (except that the presence of a linguiform process is not compared to 44° for that of the type species, as known). In the absence of features linking this pla te to measured on CPC25337. any of the recorded brachythoracids from Buchan or JOHN A. LONG

Fig. 7 —A , E, Taem asosteus m aclartiensis sp. nov., right anterior lateral plate in A, anter ior, and E, mesial views. NM VP 159891, x l. B, C, D , Taem asosteus cf. T. novaustrocam bricus. B, C, m edian dorsal plate in B, posterior and C, ventral views, NMVP159 888, x0.8. D, right interolateral plate, NM VP161865 in anterior view, xl.5. F, Brachythoraci d euarthrodire, genus indeterm inate, left sub­ orbital plate in lateral view, NM VP159890, x l. All whitened with am m onium chloride.

Fig. 8 —Com parison between A , Taem asosteus m aclartiensis and B, T. novaustrocam bricus nuchal plates in ventral view. A , restoration based on holotype, NM VP159887, B, from W hite (1978, fig. 78). C-F, com parison between palaeacanthaspidoid m edian dorsa l plates in left lateral (C, E, G) and ventral (D , F) views. C, D, M urrindalaspis wallacei gen. et sp. nov. E, F, W eejasperaspis gavini. G, Palaeacanthaspis vasta. E, F, G from W hite (1978, figs 12, 15, 19). cr.d, m edial dorsal crest; inp, infranuchal pit; inr in­ franuchal ridge; m pr, m edian ventral process; oa. P N u, area overlapped by paranuchal plate; ppr, paved posterior processes at base of crest; vk, m edian ve ntral keel. NEW PLACODERM FISHES 183 184 JOHN A. LONG

Taemas I refer this suborbital plate to indetermina te primitively absent in placoderms (Miles & Dennis 19 79, Euarthrodira. Young 1981b, Denison 1978). I conclude that on the similar development of a complex ornament Murrin­ DISCUSSION dalaspis is the sister taxon of Weejasperaspis. Young

S ome C omments on P hylogenetic P ositio ns of (1980) has noted the close similarity between the

P lacoderms from B uchan trunkshield of Weejasperaspis to Brindabellaspis, com­ The phylogenetic position of the placoderms menting that they are probably closely related. Until Buchanosteus, Arenipiscis, Errolosteus and Taemaso- more remains of Murrindalaspis are found it will be steus has been thoroughly discussed by Young (1979, unknown whether this genus is more closely related to 1981b, with further comments on Buchanosteus by Brindabellaspis than to Weejasperaspis. Denison (1978), Dennis-Bryan & Miles (1983), and C omparison o f the I chthyofauna from B uchan W hite (1978), and on Taemasosteus by W hite (1978) and The ichthyofauna from the Buchan Group closely Denison (1978). Young concluded that these euar- resembles that of the contemporaneous M urrumbidgee throdires are primitive phlyctaenaspidoids relative to the Group, New South Wales. Both faunas contain the well known coccosteomorphs and higher groups such a s following taxa, most being endemic to southeastern pachyosteomorphs. Taemasosteus is regarded as the Australia: most specialized of the Buchan/Taem as euarthrodires by virtue of the shortened trunkshield, and may be the sister taxon to Tityosteus from the Lower Devonian Euarthrodira Rhineland fauna of Germany (Gross 1960). T. maclar­ Brachythoracid phlyctaenaspidoids tiensis is undoubtedly a sister species to T. Buchanosteus confertituberculatus, Arenipiscis westolli, novaustrocambricus and does not share any extra Errolosteus goodradigbeensis, Taemasosteus features with Tityosteus to indicate otherwise. novaustrocambricus. Murrindalaspis is a palaeacanthaspidoid (sensu M iles Petalichthyom orpha & Young 1977) known only from the median dorsal Wijdeaspis warrooensis plate. O f the palaeacanthaspidoids in which this plate is In addition the palaeacanthaspidoids from both known (Dowbrowlania, Kimaspis, Kosoraspis, faunas are closely related forms (Murrindalaspis and Palaeacanthaspis & Radotina Denison 1978, Wee­ Weejasperaspis), and appear to represent the youngest jasperaspis W hite 1978) only Palaeacanthaspis and Wee­ members of this group worldwide (with Brindabellaspis jasperaspis possess a well-developed high median dorsal Young 1980) as almost all other palaeacanthaspids a re crest com parable to that in M. wallacei, although both described from Gedinnian or Siegenian deposits Kosoraspis and Radotina possess small median crests (Denison 1978). The petalichthyid Wijdeaspis is also sim ilar to (Stensio 1969, W estoll 1967). Three M. bairdi known from the Middle Devonian of Spitsbergen and characters can be utilized in an hypothesis of rela tion­ Severnaya Zemlya (Young 1978), so its Australian oc ­ ships based upon the median dorsal plate of palaeac an­ currence appears to be slightly older (Emsian). The thaspidoids: development of the median dorsal crest, lungfish Dipnorhynchus occurs at Buchan and in the development of a median ventral ridge, and the com­ Taem as/W ee Jasper faunas, as well as in the Lick Ho le plexity of the ornamentation. All placoderms primi­ Limestone near Kiandra (Campbell & Barwick 1982). tively possess a simple tubercular ornamentation The German occurrence of Dipnorhynchus lehmanni (Denison 1978, Janvier & Pan 1982), which may develop (Lehman & Westoll 1952) from the Rhineland faunas into complex linear ridges, reticulate networks or com­ has been commented on by Campbell & Barwick (1983) plex ridged tubercles in different lineages. The pr esence as probably referrable to the Australian genus of a complex ornam ent pattern, of similar organization, Speonesydrion, making Dipnorhynchus an endemic between and taken with Murrindalaspis Weejasperaspis, A ustralian genus. The fish faunas from the Lower De vo­ their overall similar shape and proportions suggests a nian of Australia contain mostly endemic genera which close relationship between these genera. Although m e­ has led Young (1981a) to suggest that East Gondwana dian dorsal crests have been independently develope d in formed an endemic province in the Early Devonian. different lineages of placoderms ( Wuttagoonaspis M ore systematic description of Australian Early Dev o­ Ritchie 1973, groenlandaspids Ritchie 1975, Byssacan- nian fish fossils is necessary before detailed com p arisons Denison 1978, Long thus Bothriolepis cullodenensis with Northern Hemisphere fish faunas can be evaluated 1983a) and may generally be attributed to similar f unc­ fully. tion (homoplasy), the ornam ent patterns are rarely very similar in different groups, except for primitive g roups which share a plesiomorphic dermal ornam ent (e.g. a c- ACKNOWLEDGEMENTS tinolepidoids and yunnanolepidoid antiarchs) or Sincere thanks to Dr. Gavin Young, Bureau of broadly similar patterns (e.g. phyllolepids, Wut­ M ineral Resources, Canberra, for helpful discussion s on tagoonaspis, Holonema). The ventral keel of Wee­ the placoderm fossils from Buchan and access to collec­ jasperaspis is interpreted as a specialization, presum ably tions of Taemas placoderms in the BMR, and to Peter for articulation of an intermyotomal submedian dors al Forey and Colin Patterson, British M useum of Natura l plate, as in higher euarthrodires. The ventral keel is History, London, for allowing me to study the NEW PLACODERM FISHES 185 placoderms from Taemas housed in the British L ong , J. A . & T urner , S., 1984. A checklist and bibliography M useum. Dr. Gavin Young and Prof. Ken Campbell are of Australian fossil fishes. In Zoogeography and thanked for critically reviewing the m anuscript. I would Evolution o f Australian Vertebrates, M . Archer & G. Clayton, eds, Hesperian Press, Perth, 325-354. also like to thank the many people who helped colle ct M c C oy , F., 1848. On som e new ichthyolites from the Scotch specimens from Buchan, for without their enthusiasm Old Red Sandstone. Ann. M ag. Nat. Hist. Ser. 2, 2: this paper could not have eventuated: Drs. E. Fordy ce, 297-312.

D. Holloway and P. Jell; Mr. M. W allace, R. Baird, B. M c C oy , F., 1876. Prodrom us of the palaeontology of Vic­ M unro, R. Brown, K. Simpson, Miss J. Dowling, Miss toria. D ecade 4. Governm ent Printer, M elbourne.

K. Orth and Mrs. D. Long. Dr. T. Rich, and Ms. E. M ark -K ur ik , E., 1973. Kim aspis, a new palaeacanthaspid Thompson, M useum of Victoria, were most helpful in from the Early Devonian of central Asia. Eesti N SV allowing me to work with the collections of the M us eum Taed. Akad. Toim. 22: 4: 322-330. of Victoria, and M r G. Quick, M elbourne University, L ehmann , W . M. & W estoll , T. S., 1952. A primitive dip- noan fish from the Lower Devonian of Germ any. Proc. perm itted loan of M elbourne University specimens. T his R. Soc. Lond. (B) 140: 403-421. work was carried out under tenure of a Rothmans M il es , R . S., 1967. O bservations on the pytctodont fish Rham- Postdoctoral Fellowship at the Australian National phodopsis W atson. J. Linn. Soc. Zool. Al: 99-120.

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M ulde. Palaeontographica 113A: 1-35. R it ch ie , A-, 1973. W uttagoonaspis gen. nov., an unusual G ross , W ., 1960. Tityosteus n. gen., ein riesenarthrodire aus arthrodire from the Devonian of W estern New South dem rheinischen Unterdevon. Palaont. Z. 34: 263-274. W ales, Australia. Palaeontographica 143A: 58-72. H il ls , E. S., 1936a. Records and descriptions of some R it ch ie , A ., 1975. G roenlandaspis in Antarctica, Australia Australian Devonian fishes. Proc. R. Soc. Viet. 48: and Europe. Nature 254: 569-573. 161-171. S tensio , E. A ., 1945. On the heads of certain arthrodires. 2 . H il ls , E. S., 1936b. On certain endocranial structures in Coc- On the cranium and cervical joint of the Do- costeus. Geol. M ag. 73: 213-226. lichothoraci. Kung. svenska VetenskapAkad. Handl. J aekel , O ., 1911. Die W erbeltiere. Eine Ubersicht uber die (3), 22: 1-70. fossilen und lebenden form en. Berlin. +252 p. S tensio , E. A ., 1969. Elasmobranchiomorphi Placodermata J anvier , P. & P an J ia ng ., 1982. H yrcanaspis bliecki n. g. n. Arthrodires. In Traite de Paliontologie, J. Piveteau, sp., a new primitive euantiarch (Antiarcha, Placo­ ed., M asson, Paris, 71-692. dermi) from the M iddle Devonian of northeastern T eichert , C. & T alent , J. A ., 1958. G eology of the Buchan Iran, with a discussion on antiarch phytogeny. N . Jb. area, east G ippsland. M em s. geol. Surv. Viet. 21: 1-52. Geol. Paleont. A bh. 164: 364-392. T homson , K. S. & C ampbell , K. S. W ., 1971. The structure L ong , J. A ., 1982. The history of fishes on the Australia n con­ and relationships of the primitive Devonian lungfis h tinent. In The fossil vertebrate record o f Australasia. Dipnorhynchus sussm ilchi (Etheridge). Bull. Peabody P. V. Rich & E. Thom pson, eds, M onash University M us. N at. H ist. 38: 1-109. off-set printing unit, M elbourne, 53-85. T urner , S., J ones , P. J., & D raper , J. J., 1981. Early D evo­ L ong , J. A ., 1983a. New bothriolepid fishes from the Late Devonian of Victoria, Australia. Palaeontology 26: nian thelodonts (Agnatha) from the Toko Syncline, 295-320. western Q ueensland, and a review of other Australia n

L ong , J. A ., 1983b. D evonian fi.-hes in Victoria. Labtalk, Oc­ discoveries. J. Bur. M in. Res. Geol. G eophys. 6: 51-69. casional Papers in Earth Sciences, N ov.-D ec. 1983: W estoll , T . S., 1967. Radotina and other tesserate fishes. J. 19-26. Linn. Soc. Zool. 47: 83-98.

L ong , J. A ., in press. New phyllolepids from Victoria and W h it e , E. I., 1952. A ustralian arthrodires. Bull. Br. M us. N at. the relationships of the group. Proc. Linn. Soc. H ist. Geol. 1: 249-304.

N .S. W. W h it e , E. I, 1978. The larger arthrodiran fishes from the area 186 JOHN A. LONG

of the Burrinjuck Dam, N.S.W . Trans. Zool. Soc. throdire) from the Early Devonian of New South Lond. 34: 149-262. W ales. J. Linn. Soc. Zool. 66: 309-352.

W hit e , E . I. & T oombs , H . A ., 1972. The buchanosteid arth- Y oung , G. C., 1980. A new Early Devonian placoderm from rodires of Australia. Bull. Br. M us. Nat. Hist. Geol. New South W ales, Australia, with a discussion of 22: 379-419. placoderm phylogeny. Palaeontographica 167A: 10-76.

Y oung , G. C ., 1978. A new Early Devonian petalichthyid fis h Y oung , G. C ., 1981a. Biogeography of Devonian vertebrates. from the Taem as/W ee Jasper region of New South Alcheringa 5: 225-243.

W ales. Atcheringa 2: 103-116. Y oung , G. C., 1981b. New Early Devonian brachythoracids

Y oung , G. C ., 1979. New information on the structure and (placoderm fishes) from the Taem as/W ee Jasper regio n relationships of Buchanosteus (Placodermi, Euar- of New South W ales. Alcheringa 5: 245-271.