;oolo,qiml ,Joumnl of the /,innpan So&& (1988), 94: 233-258. \Vith 16 figures

A new camuropiscid arthrodire (Pisces: Placodermi) from Gogo, Western Australia

JOHN LONG F.L.S.

Geology Department, Uniuersily of Tasmania, P.O. Box 252 C, Hobart, Tasmania, Australia 7001

Receir'ed J u l p 1987, accepted,fi,r publication December I987

A new camuropiscid arthrodire, Latocamurus coulthardi gen. et sp. nov., is described from the Upper Devonian Gogo Formation, Western Australia. Latocamurus, known from two complete specimens. i s recognized as a carnuropiscid by its narrow, spindle-shaped armour, dccp postnasal plates participating in the orbits, prcorbital plates which meet mesially, cheek unit firmly sutured to skull roof, posterior cheek plates tightly interconnected and much reduced, and the robust durophagous dentition. I t i s characlerizcd by its downturned siiout, broad, flat rostral plate, and narrow, deep parasphenoid. I t is placed phyletically as the plesiomorphic sister taxon to all other caniuropiscids which are more derived in having, inter a h , an antrrior lateral plate which arireriorly contacts the anterior vcritrolateral plate and pointed rostral plates. T h e family Camuropiscidae Dennis & Miles 1979h i s redefined to incorporate features of the new genus. Carnuropiscids arid Incisoscutnm are closely related by fcatures of thc postnasal plate and cheek.

KEY \\'ORDS: anatomy - phylogeny.

Devonian - Australia - camuropiscid - arthrodire new species - ethmoid

C O N T E N 1 3

Introduction . . . . . . . . . . . . . . . . . . . 233 Systematic palaeonrology . . . . . . . . . . . . . . . . 235

Family Carnuropiscidar Dennis & Miles 1979b. . . . . . . . . . 235

Latocamurus coulthardi sp. nov . . . . . . . . . . . . 238

Parasphenoid. . . . . . . . . . . . . . . . . . 250 Ethmoid ossification . . . . . . . . . . . . . . . . 25 I

Relationships of Latocamuruj gen. no\ . . . . . . . . . . . . . 254 Conclusions . . . . . . . . . . . . . . . . . . . 256 Ackriowlcdgcmrnts . . . . . . . . . . . . . . . . . 256 References. . . . . . . . . . . . . . . . . . . . 256 Abbrrviations used in the figures . . . . . . . . . . . . . . 257

Latocamurus gen. nov . . . . . . . . . . . . . . . 235

Additiutial points of structure . . . . . . . . . . . . . . . 250

IN'I'KODUC'IION

Since the first collections of fossil fishes were made from Gogo in the 1960s a series of important papers has been published dealing with the placoderms (Miles, 1971; Miles & Dennis, 1979; Dennis & Miles, 1979a, b, 1980, 1981, 1982, 1983; Dennis-Bryan, 1987; Miles & Young, 1977; Young, 1984;

233 0024-4082/88/110233 + 26 $03.00/0 1988 The Liiineaii Society of L.ondon

231 J . LONG

Fore)- & Gardiner, 1986), lungfishes (Miles, 1977), palaeoniscoids (Gardiner, 1913, 1984; Gardiner & Bartram, 1977) and the crossopterygians (Long, 1985). Still au.aitirig publication are works dealing with Onychodus (by Dr S . M. Atidrews), the four or so new species of coccosteids and Bothridepis (>by Dr Dennis Bryan, Prof. B. Gardiner and Dr R . S. Miles). All of these papers have t o some extent made an impact on our views of early vertebrate evolution, and some controversy has arisen over the problem of tetrapod ancestry (Rosen, Forcy, Gardiner & Patterson, 1981) based on new anatomical data from Gogo

lilrs, 1977). This fauna is regarded as one of the world’s most important assemblages of‘ Devonian fishes because of the extraordinary preservation of‘ anatomical detail afforded by the acetic acid preparation of the specimens. All of the above works are the result of the first two collections (1963, 1967), most ot‘ vvhich arc held in the British h4useum (Natural History).

Dennis-Bryan (1987: 2) states that the 1967 tripartite expedition comprised Dr C. H. C. Brunton (British Museum), Dr W. D I. Rolfe (Hunterian Museum) and Dr K. S. 1%‘. Campbell (Australian National University), but in fact Campbell collected material on an independent trip later in the early 1970s, as did Gavin Young and Alex Ritchie. M r H . A. Toombs (British Museum) was the expedition leader and the australian contingent consisted of George Kendrick, Ken Butler and David Cliff all from the Western Australian lluseum. It should be noted that Dr Curt Teichert, during his Canning Basin fictld trips of the late 1930s to early 1940s was the first person to recognize ‘coccostean’ fish remains from the Manticoceras zone in limestone concretions (Teichert, 1949), and not Dr Basil Balme as stated by Ritchie (1985). ‘Teichcrt collected Gogo fishes which were reposited in the collections of the University of’ Ct‘estern Australia Geology Museum, and also found the skull of a new genus of’ dinichthyid from a Famennian horizon in the same region (Long, 1987~11. Denis-Bryan (1987) states that the entire collecting area of the 1967 expeditioli was within Gogo Station, whereas today many of the important Gogo localitics arc situated on the adjacent Christmas Creek Station (Paddy’s Valley, Bugle Cap and Teichert (Hills). Although Gogo Formation as mapped by Playford & Lowry (1966) is exposed over a large area within Gogo and Christmas Creek Stations. it is only in restricted regions where weathering has produced a significant concentration of Gogo concretions that fish can be found in abundance.

This paper represents a new generation of work on the Gogo fauna resulting from material found on the 1986 and 1987 Gogo expeditions sponsored b y thc National Geographic Society. The new material, all of which shall be reposited i n the Western Australian Museum, includes the new arthrodire described here a s well as other new species; a complete skull of the osteolepiform Gogonnsus (Long, 1985); previously undescribed material of the tail and pelvic girdle of Holonemci utestolli (Miles, 197 1); a complete specimen of the poorly known ptyctodontid Chnpbellodus decipiens (Miles & Young, 1977); new information on previousl) described arthrodires (Long, 1987b; 1988, and several skulls and hodirs of lungfishes, including a new genus of chirodipterid and a new species ol‘ Holod$terus, which are being studied by Prof. K. Campbell and Dr R . Barwick at the Australian National University.

As the previous Gogo arthrodires have been described in great detail, and thr. new form does not differ significantly from the other camuropiscids in man). points of anatomy, I shall leave the illustrations to show the shape and form of

N E b ’ AUSTRALIAN ARlHRODlRE: 235

these components, as adopted by Miles & Dennis (1979) and Dennis & Miles (1979- 1983). The description will follow the numbered character scheme of Miles & Dennis, but where morphological features are essentially the same as in the other camuropiscids this will be noted and no further comments made. As the material is uncrushed and three-dimensionally perfect, there is complete confidence in the given restorations of the armour, and therefore only unusual features of the new genus will be described. Measurements (Table 1 ) follow the scheme adopted by Miles & Dennis (1979) and Dennis-Bryan (1987).

SYS’IEMA’I’IC PALAE:ON‘I’OI.OGY

Order Euarthrodira Gross 1932 Suborder Eubrachythoraci Gross 1932

Family Camuropiscidae Dennis & Miles 197913 Diagnosis

Small eubrachythoracid arthrodires which have the following derived features: elongated, narrow body shape with large orbits; postnasal plates large, excluding contact between the suborbital and preorbital plates; rostral plates either broad and flat or tubular in presumed advanced species; preorbital plates having mesial contact; suborbital plate firmly sutured to skull roof; postsuborbital and submarginal reduced and tightly interconnected to each other; dentition durophagous with thick, rectangular posterior superognathals; postmarginal sensory-line canal not present, and main lateral line canal having a ventral course o n the anterior dorsolateral plate.

Remarks The above diagnosis has been amended from Dennis & Miles (197913: 298) to

exclude features of Carnurapiscis, Rolfosteus and Tubonasus which are not seen on the new form. The Camuropiscidae are an endemic group of specialized arthrodires known at present only from the Gogo Formation.

Referred taxa Carnurapiscis concinnus, Carnurapiscis laidlawi (Dennis & Miles, 1979a), RolJosleus

canningensis, Tubonasus lennardensis (Dennis & Miles, 1979b), Latocamurus coulthardi gen. et sp. nov.

Latocamurus gen. nov.

Etyma Logy

the rostral plate. From the Latin latus, broad, and camurus, a flat nose, alluding to the shape of

Diagnosis A camuropiscid arthrodire having a headshield with a breadth/length index

of c. 65, and orbits which are 4404 of the postpineal length of the headshield. Headshield breadth equal to postpineal length of skull roof. The snout is strongly downturned. The rostral plate is broader than long, with a weakly convex anterior margin and four concave margins for contacting the postnasal and preorbital plates. The suborbital plate has a deep and well rounded

236 ,J . LONG

postorbital division, and the postsuborbital is larger than the submarginal which is firmly sutured to the marginal plate. The anterior and posterior superognathals have a central row of broad, rounded tubercles; the irifixrognathal lacks teeth having only broad crushing surfaccs. ' lhe para-

NEW AUS'I'RALIAN AR'I'HRODIRE 237

E'igurc 2. Latocamurus coulthardi gen. et sp. nov. A. armour in latcral vicu (dusted wit11

ammonium chloride]; B, intcrprctation of katurrs iuppcr .jaw toothplatcs addcd). \ V A M 86.9.699.

sphenoid is very narrow and deep in profile, with a crescentic ledge posterior to the huccohypophysial foramina on the ventral surface. Trunkshield has a breadth/length index of 46; the median dorsal plate has a sharply pointed posterior margin, and the spinal plate is long, separating the anterior lateral from contact with the anterior ventrolateral; anterior median ventral plate with narrow tapering posterior lobe which has short contact with posterior median ventral plate.

Remarks Latocamurus is readily distinguished from the other camuropiscids by its

broader headshield with downturned snout, blunt rostra1 plate and long spinal plate which excludes the anterior lateral plate from contacting the anterior ventrolateral plate. It also differs in other minor features such as the shape of the pineal and postnasal plates and in features of the parasphenoid. The characters it shares with other camuropiscids are discussed in the phylogenetic section at the end of this paper.

Type species Latocamurus coulthardi sp. nov.

238 J . LONG

TABLE 1 . hleasurcments ( m m ) of Latocamurus coulthardi gen. et sp. nov. based on the schemr of Miles & Dennis (1979)

H h t ! pc 'vY.111 86.9.699 ~ ~~~ ~~~~~~ ~ ~~ ~~~~~~ .

Lciigtli (11' skull 1 6 Brcadtti of skull across postri-ol~itrr~d ai igl~~s

Uqxh ( i f skull 21 4

Lerigt ti d o r h i t 1 1 5 I.ellg'h of XI: I5* 1 3 7

1)cprh of Intrral articular fossa L. 2 ( . 1.8

31 26 Rrradtli o f skull across postrromcsial angler

I'rcpiIi(,;iI length I3.j

Leiigtli o f la tcrd articular fossa 3.7 2.6

.\iiglc I)ct~vr.cn axis of 'trticular f i i s s a arid

lxng th i i E r.licck 35* 31) ,j I.c~tgrh of postortiital di\ iairiii ol'cticck 1%5* Ib.5

d(irscilatera1 surfacc or skull ( . 30

I.cllgth of If: 34 1,crigth 01 biting dilisioii of I fy I6 12 Length of t~.urrk sliicld 88 63.5

Dcprh 01' t in ink shield :i:i Ro~ri-oc;iudal Icngth of I l m k iii-iiiour 23* 1 7 I.cngtl1 of ["'tol-al lcncstr'l 17.5 9 T Lclrgttl of S1U 37 -. ' I ( ) 5 Rrc'ltltll 01 \ l l ) 21.5 19 lrcllgtll 0" sp 13 9 A n g k l)rr\iecii Sp and rostr(icaiidaI

axis of iirmour 0 0 1"~Ilgrh ol'.\\.l. 37 28 I.ciigth of spinal tlivisioir of h1.L 22.5 I l i . 7

Hi-cadtti d ' 1 r u n k shield i. 4 2 3 I

Latocamurus coulthardi sp. nov. (Figs 1-15)

I.:1 I'?rlolo<gJ I n honour of Mr ,Jim Coulthard, district rnanager of Christmas Creek and

Gogo Stations, who kindly permitted us to collect specimens.

.llaleTial Holotype, \VAM 86.9.670 (Figs 4, 5) , a complete armour, partly articulated,

prepared out ns two halves by the resin transfer method (Rixon, 1976). t V A M 86.9.699, complete specimen.

Luccilz(v and horizon Holotype collccted by the author on 17/8/1986, from approxitnatel) 100 m

south-west of 'Stromatoporoid Camp' (close to locality no. 20 of Miles, 1971, fig. 1). WAM 86.9.699 collected by the author from the north-eastern side of Paddy's Vdlley in June 1987. Late Devonian (Frasnian) Gogo Formation.

NE\V AUSTRALIAN ARI‘HKODIKE 239

Figure 3 Latocamurus coulthardi gen. et sp. nov., tiendshield 111 \entrdl tic\\, \Z 411 86 9 63’) 1 cinbrrd wi th ammonium chloridc)

Descriplion ‘l’he general shape of the armour (Figs 1, 2 ) , like that of the other

camuropiscids, is elongated and narrow, but not as streamlined as in presumed advanced members of the family. Proportions of the armour (Table 1 ) can be directly compared with the other camuropiscids.

‘The headshield (Figs 1-3) is narrow (breadth/length index 65) with large orbits which are approximately 4 4 O , of the postpineal skull length in diameter, similar in size to that of Cumuropiscis concinnus (4.27,). The rostra1 plate is variable in the two specimens (Figs 1, 7B) but is consistent in its broad shape with a weakly convex anterior margin and large overlap areas for the postnasal and preorbital plates. I’he pineal is cruciform in the holotype (Fig. 7A), but what is preserved of it in WAM 86.9.699 (Fig. 1) is similar to that of Cumuropiscis. The preorbitals have a short area of mesial contact just anterior to the pineal plate, and a deep descending lamina with large overlap surfaces for the postnasal plates. They are arched anteriorly. l’he postnasal plates (Figs 3, 4, 7A, 8, 15A) are very large and deep, and participated in the anterior margin of the orbit. They have separated contact margins for the suborbital (oa.SO) and preorbital

ioa.PRO: plates (Fig. 81, indicating that these plates did not contact each other behind the postnasal in the articulated armour as occurs in Incisosculum (Dennis 8r hiiles, 1981 ) . There is a horizontal lamina of bone projecting at a right angle to the surface of the postnasal for overlap of the rostra1 plate (oa.R, Fig. 8 ) . In the articulated armour the postnasals are orientated vertically to enclose a box-like space between themselves and the skull roof (Figs 3, 1.5). Thc. postorbital. marginal and paranuchal pIates bear n o special features; their outlines can be seen from the figures. The central plates show clearly the middle and posterior pit-lines. The postmarginal plate is entirely tucked into thc subobstantic area of the headshield (soa, Fig. Z), and lacks an) dermal ornamentation on its lateral surface. The ventral aspect of the nuchal platc. has a iveak nuchal thickening with paired infranuchal pits (pt.u, Fig. 3 i , arid numerous nutritive foramina in its central region. The triangular dcprcssion noted on the visceral surface of the marginal plate of Camuropiscis b y Dennis 8 nliles (1979a: fig. 16) is well developed in Latocamurus itri, Figs 3, 13A) . ' l ' h c c long quadrate (Qd, Fig. 13) does not stretch into this depression as suggested for

hE,\.\’ AUS I RALIAX AR I HRODIKt 24 I

Figure dorsal

Camuropiscis, but bends away below this region, which was probably occupied by muscles which moved the cheek complex.

The dermal ornament is well illustrated (Figs 1 , 2, 6, 7, 9), consisting of simple low tubercles which may form a concentric disposition on parts of the ventral thoracic armour. It is not as pronounced as some of the high tubercles found on the armour of Cumuropiscis (for example see Dennis & Miles, 1979a: fig. 10B).

The following characters are now described with reference to the phylogenetic scheme of Miles & Dennis (1979) to facilitate comparisons with other Gogo arthrodires. Points of morphology identical with those on Cumuropiscis are noted but not discussed further.

1. Great width of skull roof across posterolaterul angles. The posterolateral angles are not seen in dorsal view (Fig. 1). The headshield has an overall broader shape than Cumuropiscis due to the shorter rostra1 plate, and the postpineal length of the skull, relative to its breadth is still marginally shorter (postpineal

242 J . LONG

Figurr b. Latocamurus coulfhardi gen. et sp. nov. SESI photographs of rhr drrnial omanirnt lrom t h r lrli pnstrrioi- dorsolatrral plate. Iiolotypc. A, B, Ohlique virws A. x 120; U, x 60 (:. Prrpcndicular t i) tuticrclrs x 60'1.

length/breadth skull roof being 100 for Latocnmurus, 78 Camuropisrzs, 87-88 for Tubonasus and Rolfsteus; 140 for Hanytoomhsia).

2. Two superognathals. As for other arthrodires these are paired anterior and posterior elements, both with dorsal processes developed (Figs 7A, 8, 10, 13,. IVhen articulated with the autopalatine and ethmoid bone they appear almo5t fused together, the fit between them being very close (Fig. IOA,C). ' l he anterior superognathals are robust bones having a single row of low rounded teeth present (the ventral tooth row; Dennis & Miles, 1979a; fig. 12), and lack symphysial teeth. The posterior superognathals are almost rectangular in form,

NEW AUSTRALIAN ARTHRODIRE 243

C

Figure 7. Latocamurus coulthardi gen. et sp. nov. Holotype WAM 86.9.670. A, Jaw and skull elements, x2.5 (see also Figs 5, 8) . Note the unusual shape of the pineal plate in the top right, behind the left postnasal plate. B, Ethmoid bone and rostra1 plate, ~ 2 . 2 (see also Figs 2, 11 ) . C, Median dorsal plate in dorsal view, x 1.35 (see also Figs 2, 5) .

being very thick in lateral view and with well-developed dorsal processes (Fig. 1OC). There are three large, rounded teeth situated in a lateral row, comparable to the multicuspid teeth of Bullerichthys (Dennis & Miles, 1980). The crushing teeth of Latocarnurus differ from those of Bullerichthys in lacking a dentine coat and in the absence of scattered isolated teeth. I t is clear from close

t'iqutc 8 . Latocamurus coulthardi gen. et sp. nov. Skctcli ol'jaw ehlrI i t5 . postnasal pLitcs ,tiid \c11tral surfi icc 0 1 rtllmold kxmc, holoc) pc LVAXl 86.9.670 (ace also Fig. 7'4:. 'Ttic outline ( i t ' t h c right antcrioi- superogtiatli;d i t i l i k prirition i s shown on thr vcntral surfiice of t h r rthmciid. iiidic'it(d I)! .in arrow. I n w t slro\vs t l ic p s t e r i o r process of thc left ;interior superognatli;il from tti( ,

ctiorr of the right postnasal plate in thc t(Jp Irft of tlic fqurc \ I I O M S t11c c.\tctisi\ c hcirizotital Iiimitin for the o\ crlap 0 1 ttrc r ( i s r ra l plate.

245

Figurc 9. Latocamurus coulthardi gen. et sp. nov. Ventral asprct of thoracic armour and parts 0 1 thc chcck unit . holot)-pc \VAhl 86.9.670. (dusted with ammonium rhloridc).

comparison between the dentition of these two taxa that Latocamurus was a durophagous feeder like the other camuropiscids.

3. Ginglymoid dermal neckjoint. The dimensions of this feature are stated in the measurements. It is typical of the neck joint described for other camuropiscids with the para-articular process and lateral articular fossa well developed, and a wide nuchal gap present.

4 . Median dorsal plate wilh ventral ridge. Developed as for other Gogo arthrodires.

5. Occipital cross-commissure passing of the hind margin of the paranuchal. Developed as for Camuropiscis. Extrascapular plates are not seen on either specimen.

6. Suture lines remaining distinct, sinuous in skull-roo f, whose plates have well-developed overlaps. These characters are seen in the illustrations. Some points regarding overlap relations are: postnasal plates large, preventing contact behind them between the suborbital and preorbital plates; inward lamina on the postnasal plate for overlap of the rostral plate; pineal and rostra1 plates separated by mesial contact between the preorbital plates; suborbital has an irregular

246 J . LONG

Fixutc 10. Latocamurus coulthardi gen. et sp. nov. Ethmoid bone with associated p.ir.i~phciioicl and toothplnrca of the right side. lVAh1 86.9.699. A, Antcrior \iw'; B. oblique. kf t I;itcIal \.ic\v; C. ventral view. A, B? C, x 4.4. D, oblique ventral \icw of anterior of hcad s l iowin~ cthmoicl boric.. parasphrnoid and right supcrognathals in lifc position, x 2.5. (All dustcd w i t h ammonium chloride I

posterior margin where the postsuborbital plate is firmly sutured; submarginal plate has large dorsal overlap flange for marginal plate; central platr has a long suture with postorbital plate, excluding contact between the paranuchal and preorbital plates; anterior lateral not contacting the anterior ventrolateral due to long spinal plate; extensive contact margin betwecn the anterior latcral ancl interolateral plates; posterior lateral has a dorsal overlap surface for thc posterior dorsolateral plate; anterior median ventral and posterior median ventral have a short median contact margin.

7. -tuchal plate posteriorb expanded. As for Camuropiscis. 8. Paranuchal plate with postnuchal process. As for Camuropiscis. 9. Xuchal thickening on zlisceral surface o f skull roof. As €or Camuropiscis.

10. Paired pits on uisceral surface of skull roof. As €or Camuropiscis. 11. Pre-endol_vmphatic thickening. As for Camuropiscis. 12. PPcLomIjn long, horizontal base articulating against laterally, facing scapulocorrrroid.

NEM' AUSTRALIAN AR'I'HRODIRE 247

A

Figui-c I I . Latocumurus coulthardi gen. et sp. nov. Parasphrnoid in A, ventral, B, dorsal and C:. oblique lateral \ icws. Holotypc LVAM 86.9.670.

Presumed to be as for Camuropirczs, except that the spinal plate is slightly longer. 13. ~nferog~ialhal wilh both blade and biting regiom, which are complele and co-ossified.

The relative lengths of the biting and blade divisions of the inferognathal are exactly the same as in Camuropiscis. The mesial groove is not seen. The biting region is thick with a flat occlusal surface lacking any cusps, but with shallow depressions opposing the blunt teeth of the posterior superognathals (Fig. 2) . The anterior end of the biting region is narrow with an anteroventral thickening present. The mentomeckelian and articular ossifications are well preserved, the former being anteriorly narrow but very deep and thin posteriorly; the articular is essentially as in Camuropiscis with a relatively high articulation surface and a well formed posterior process.

14. Skull-roof with lateral consolidated region. Visceral features of the skull-roof are shown in Fig. 3. The left postorbital shows this feature well developed (Fig. 13A) as a triangular depression exactly similar to that of Camuropiscis (Dennis & Miles, 1979a: fig. 16). No inframarginal crista (sensu Miles & Westoll, 1968) is developed.

15. Submargznal plate small and closely incorporated into cheek unit. The externally exposed surface of the submarginal (Fig. 2) is quite small as in the other camuropiscids, with irregular contact margins for both the postsuborbital and marginal plates. The submarginal has a long anterior lobe, but does not preclude contact between the suborbital and marginal plates. It meets the postsuborbital along an irregular suture.

16. Skull-roof with well deueloped supraorbital vault. As for Camuropiscis, including the delicate ventral post-ocular process developed (pt.o.pr, Fig 3 ) .

17. Suborbital plate with slender suborbital laminae. The suborbital has a shorter suborbital lamina than that of Camuropiscis, with a deeper, more rounded

A

nos. cap

tub

nos cov

br.cov pr.pos

5 rnm

3 nos cop

postorbital division (Fig. 2 ) . There is an extensive anterodorsal overlap margin for the postnasal plate and a well marked suborbital crista (cr.so, Figs 3, 13;). 'l'he posterior margin of the suborbital is notched for a firm suture t o the postsuborbital plate.

18. Medinn dorsal Plnte with carinal process. The carinal process jcr.pr, Fig. 2 j is quite broad, and stout, directly comparable with that of other camuropiscids. The posterior margin of the median dorsal plate is pointed but not drawn out

N Lit’ AUSTRAL1 AN AKTHRODIKE 249

’ / ’ I crn

pr det

t‘igurr 13. L Q ~ O C U ~ U ~ S S coulthardi gen. et sp. nov. A, A’, Stereo pair showing features of the \isccral surfacr of the check and skull roof. Notr the long quadrate which hcrrds vrntrally brforc rcncliing the triangular deprcssion on the postorbital plate. B, Features of the check complex in \ iscrr;il \ . i rw. iY.411 86.9.699.

into a spine as in Harrytoombsia. The sides of the median dorsal plate are parallel for about half the plate length in the holotype (Fig. 7C). The anterior margin comprises two strongly convex sides (Figs 1, 7C). The sub-median dorsal bone is slender as in Camuropiscis.

19. Prcorbital plate with preorbitaal lamina. As €or Camuropiscis except that the preorbital plate is arched throughout its anterior half to give the snout its downturned appearance (Fig. 2) . The postnasal plates are curved in cross- section having a short dorsal division and a larger lateral lamina posteriorly. The postnasal plate is quite deep, the depth/length index being 64 (Figs 2, 8). ‘The supraorbital sensory-line canal runs off the postnasal plate at the anterior free margin which is not in contact with other plates (Fig. 15).

20. Suborbital plale with internal laminae. As for Camuropiscis, described under 17. 21. Palaloquadrate with separate autopalatine and quadrule bones. The auto palatines

are well preserved attached to the lateral faces of the ethmoid bone (Figs 10-13). In both specimens the autopalatine is fused to the ethmoid ossification to give great rigidity to the attachment surface for the superognathals. The quadrates are long perichondral ossifications bearing articulatory condyles and a small elongated detent process (pr.det, Fig. 13) near the ventral end of the

250 J LONG

bone. The anterior end of the quadrate is very narrow, almost slit-like. As in Camuropurz r the quadrate reaches towards a triangular depression on the postt"rhit,il bone (Dennis & Miles, 1979a fig. 16), but in Latocamurur i t cur\es

22. SuI)a~ognathalJ tedh postpilor procasser. The toothplates have ahead) been entrally before meeting the triangular depression (Fig. 13A)

described no. 2 ) .

ADDITIOSXI. 1'OlXl.S OF STRUGTIIRE

In this section the parasphenoid and ethmoid ossification of the braincase are described. The pclvic girdle of WAM 86.9.699 is well-preserved but is identical l o that of Camuropiscis concinnus and is not described here. Fragments of the scapulocoracoid and the vertebral skeleton are preserved posterior to the trunk ximiour in the holotype (vert, Fig. 5) but these do not differ significantly from those described for other Gogo arthrodires (Dennis & Miles, 1981 ; Dennis- Br, ;m, 1987) to ivarrant firrther comment.

T h e parasphenoid

T h i s boric. (Figs 10- 12) is similar in its narrow shape and deep profile to that ol' Ijruntonichthys (Dennis & Miles, 1980; fig. 4) and Tubonasus (Long, 1988). It is pc.rf'crtly preserved on WAM 86.9.699, still articulated to the ethmoid ossification, where it juts out at an angle of c. 45" from the horizontal plant, of' the autopalatine-ethrnoid suture (Fig. 10B). O n the holotype it sho\vs thc. complete dorsal and lateral surfaces and part of the Lrentral surface which \ \ -as damaged through the plane of splitting when the specimen was fourid (Fig. 1 1 I .

'I'hc ventral surface (Figs IOC, 1 I A ) consists of a smooth, deeply grcto\~d anterior division with a central median crista (cr.m.), and a relatively flat posterior division, the two divisions being separated by a prominent curved ledge (le), just posterior to the depression for the bucohypophysial foramina il>.hyp). There is a short lateral groove (gr.a.com) for the interrial carotid arteries as in the other Gogo arthrodires. The ventral division has a narrow transverse groove for the lateral branchcs of the hypophysial vein (v.1.h) p I .just anterior to the large central foramen for the posteriorly directcd median hypophysial vein (v.m.hyp). Numerous foramina (for) are scattered over the surface of the bone between the small transverse groove and the ledge on the holotype parasphenoid.

In dorsal view (Fig. 11B) there is a small triangular surface which contains the paired ovoid depressions, presumably for the lobus hypothalami, in which the buccohypophysial foramina (b.hyp) are located. There is a deep lateral groove (t.l.gr) on the dorsal surface just posterior to the median process in1.p~). The grooves on the dorsal surface run into the centre of the bone from a dorsolateral direction, rather than horizontally, as do the transverse latera! grooves on the ventral surface of the parasphenoid. This suggests that the grooves on the dorsal surface may have been for veins draining downwards into the median hypophysial vein which then courses posteriorly through the bone via a small foramen (v.m.hyp). An unusual feature of the dorsal surface of the parasphenoid of Latocamurus is the presence of a well pronounced median process m.pr) posterior to the buccohypophysial foramina.

NEW AUSl’RAI.IAN ARTHK0I)IRE 25 1

The deep, narrow form of the parasphenoid in Latocamurus and Tubonasus would suggest that this is a specialized feature of the Camuropiscidae (noting that the parasphenoid has not been described for Camuropiscis or RolfsteuJ). Close morphological relationship between Tubonasus and Rolfsteus suggests that the parasphenoid of Rolfosteus is predicted to be of the narrow, deep type.

The ethmoid ossijication

The ethmoid ossification (rhinocapsular bone; Stensio, 1963) has been described in three other Gogo arthrodires: Rolfosteus (Dennis & Miles, 1979b), Incisoscutum (Dennis & Miles, 198 1 ) and Eastmanosteus (Dennis-Bryan, 1987). Stensio (1963) has restored the ethmoid ossification from a grinding series in Tapinosteus, and described it from actual remains in some other arthrodires (e.g. Pholzdosteus, Trematosteus), and Goujet (1984) and Miles (1971), amongst others, provide descriptions of this bone for some primitive arthrodires. The ethmoid ossification of Latocamurus is perfectly preserved in WAM 86.9.699 (Fig. 10) and fairly complete in the holotype embedded in resin, showing the lateral and internal surfaces clearly, with the ventral surface preserved in the counterpart block of resin (Figs 4, 5, 7A,B, 8, 12). As in other arthrodires the ethmoid ossification has two laminae of perichondral bone enclosing an interperichondral space which in life was cartilage filled. There is no internasal bone present, although there is a stout internasal process projecting anteriorly below the nasal cavities (pr.in, Fig 12D) which would have functioned similarly to an internasal element. Unlike in Tapinosteus where the internasal process is most developed in the dorsal part of the anterior surface of the ethmoid bone (Stensio, 1963: fig. 52), the intcrnasal process in Latocamurus is ventral to the cavities for the nasal capsules.

The dorsal surface of the ethmoid is not roofed by perichondral bone but was closed over by the dermal skull roof. In dorsal view the internal surfaces of the ethmoid ossification are clearly seen (Figs 7B, 12A). It is almost square, having slightly longer anterior margin than posteriorly, and differs from that of Incisoscutum in the well defined separate rhinal lobes of the brain cavity (br.cav), which terminate at the cribrosal ossification. There are several small foramina at the anterior end of the cavity for the olfactory tract (olf), representing the filia ofactoria of cranial nerve 1 which run anterovetitrally into the nasal capsule (nascap). In addition there is a small tubule of perichondral bone running from the mesial side of the cavity, anterior to nerve 1, into interperichondral space abovc the nasal capsule, ending at a point in the midline of the capsule on its dorsal margin. This nerve tube (term?) is seen on both sides of the holotype specimen and may possibly represent the course of the terminalis nerve, previously described in only one other placoderm, the acan thothoracid Brindabellaspis (Young, 1980). In Brindabellahpis, the terminalis nerve runs from the brain cavity just anterior of the olfactory nerve into the nasal capsule, whereas in Latocamurus this nerve ends dorsal to the posterior encapsulated part of the nasal capsule, presumably entering it in its anterior half. WAM 86.9.699 shows paired perichondral tubules for the terminalis in exactly the same position. There is a large break in the dorsal rim of the ethmoid where the two rhinal divisions of the cranial cavity meet, indicating the outwards passage of a large cranial nerve, the optic nerve (gr.II), by comparison with other

252 J . LOXG

arthrodires (e.g. Tapinosteus, Incisoscutum). Behind the optic nerve foramen ihcrc tnissing the dorsal region of bone above the opening) the ethmoid terminates at the basal subocular process, here seen developed exactly as for Incisosculum.

In lateral view the ethmoid ossification (Figs 10B, 12C) shows a curved groove ( 1 .grj running from the base of the subocular process upwards then down anteroventrally ,just behind the nasal capsules where the autopalatines (Aup) are fused to the ethmoid bone. Midway along this suture is a deep excavation with two smaller pits contained inside its rim: a myodome for extrinsic eye muscle attachment (my). I t is also noted that the posteriorly facing orbital vault of the preorbital plate bears a well developed flange (PRO.fl, Fig. 14) which abuts the ethmoid bone and may have acted as an attachment area for superior and inferior obliquus muscles. The anterodorsal region of the lateral surface s1mw.s a smooth attachment area to the preorbital plates (a t t .PR0) which juts o u t as it short ledge; however, when articulated to the ethmoid bone there is a small part of' this ledge which faces posteriorly into the orbital chamber a.or.att) being confluent with the posterior orbital flange of the preorbital

platc. Figure 10D shows the ethmoid bone in life position, with upper jaw toothplates attached. Ventral to the preorbital plate attachment area is a smooth depression for attachment of the subocular process of the suborl>ital p l a t e iatt.SO). Between this region arid the preorbital attachment area is a Ivell-defined groove (gr.al.eth), possibly for passage of the orbitenasal artery and vein. O n the left side of the holotype only there is a small circular ring of bone (pp) dorsal to the suborbital attachment area which may have been for ligaments from the suborbital, although this structure is not present on \YAM 86.9.699. A large foramen penetrates the posterior wall of' the nasal capsule and runs anteroventrally into the nasal capsule, via a perichondral tube ivhich has accessory tubules of the snout sensory plexus branching off it. This c;tnal is for the profundus nerve (prof). 'Hie course of the profundus is shown in Fig. 12B, where most of the tubuli of the interperichondral space are interconnected to this main nerve pathway. Immediately ventral to the large cmbayment for the optic nerve there is a slit-like opening i n the autopalatine~ethmoid suture, possibly for passage of the orbital (or optic) artcr), ! 0rh.a. 1.

'I'he Lrentral surface of the ethmoid ossification is deeply grooved anteriorly for attachment of the anterior superognathal (att. ASg, Fig. 8), posteriorly it hecomcs steep sided to leave room for the hypophysial region where the parasphenoid attaches (Fig. 1OC). Around the anterior margin, just ventral of the curved embayments for the nasal cavities, there is a small groove (n.buc) which runs parallel with thr anterior margin of the ethmoid bone, and then posteriorly to course lateral to where the anterior superognathals were positioned. This groove was presumably for the buccalis nerve and vessels as noted for Tapinosteus and other arthrodires by Stensio (1963; fig. 50, gr.mb). 'I'he anterior superognathals attached to the ventral wall of the ethmoid at tbvo depressed regions (dep 1, dep 2, Fig. 8 ) , and a well developed ridge (ri posteromesially across the top of the superognathals, terminating at a small foramen ( f 1 ) . A second foramen (f2) opens laterally to this foramen. Evidence of another courseway for vascular or nerve supply to the snout and upper lip area is seen in the form of a very small groove (gr) running antero-posteriorly on the lateral side of the ethmoid ventral wall.

NEW AUSTRALIAN AKL'HRODIRE

PRO

253

/ I cm

E'igurc 14. Latocamurus coulthardi gen. et sp. nov. Skctch of cthmoid bone in postcrolatcral vicw situated in orbital cavity t o show relationships brtwren thr ncurocranium, dermal skull roof and chcck. \\'AM 86.9.699.

In anterior view (Fig. 10A) the nasal cavities are separated from the ventral lamina by a flat anterior lamina. This surface is interrupted by the internasal process (pr.in), bu t is otherwise featureless apart from grooves, noted above, along the ventral edge.

In none of the previously described Gogo arthrodires has the connection between the ethmoid ossification and the dermal skull roof and cheek been discussed. WAM 86.9.699 is unique in having a complete ethmoid bone perfectly preserved which can be easily fitted into life position (Figs 14, 15A) showing that there were two major pathways for exit of the nerve, artery and vein supply from the orbital region into the snout. The posterior orbital flange on the preorbital plate (PRO. fi) fits against the suborbital plate allowing the grooved anterior end of the subocular crista to run into an open groove plus foramen (gr.n.buc, Fig. 15A), presumably for the n. buccalis lateralis and n. maxillaris nerves. Mesial to this opening is a second foramen between the

B

I rm . _ - Figure 15. Latocamurus couZtlurrdi gen. et sp. nov. A, Anterior view of skull with cthmoid hone and infrrognathals in life position. B, Attcmptrd restoration of head in anterior view, srnsorv- lirirs shown as unbroken lines.

251 J . L O N G

anteromesial edge of the suborbital and the orbital attachment area on thc ethmoid hone, here termed the anterolateral ethmoid groove (gr.al.cch j . I t probably enabled the orhito nasal vein and artery to pass into the snout region as suggested for Tupinos/eu.c by Stensio (1963).

As few arthrodires have been reconstructed in anterior view I take the opportunity to prrsent such a restoration of Latocamurus. Figure 15A shows the dermal skeleton with ethmoid bone and inferognathals in life position in anterior view, and Fig. 15B shows an attempted restoration of the fish’s fact, nit11 lateral line canals shown as unbroken lines (in life these were undoubtedly pwes as in li\ing fishes). ‘I’he notch for the incurrent naris (na.in, Fig. 1514) is me11 defined between the rostral and postnasal plates. ‘Thc excurrent naris was probably situated lateral to the internasal process (pr.inj at the ventral limit of the nasal capsule.

R t:I..4‘I’IONSHIPS O F LA 7.0

The fiimilj. C.hnuropiscidae was defined by Dennis & Miles [ 1979111 t o include the genera Camuropiscis (two species; Dennis & Miles 1979a), and the unusual tubular-snouted forms Rolfosleus and Tubonasus (Dennis & Miles, 19791): Long, 1988). .\I1 three possess a n elongated armour with pointed rostra ;most dei,eioped i n Rm(fii.cleer.r and Tuhonnsus as tubular rostral plates) as well as other specializations listed in the original familial diagnosis.

Denison j 1984) suggested that the Camuropiscidae arc the sister group t o 1wi.5o.(cuIuttT i\vhich he placed in the monotypic family Incisoscutidae), a s the!, share the t‘ollowing synapomorphics:

1 1 (2) The submarginal plate is reduced more so than in typical coccosteids. 13) ‘lhe spinal plate is reduced antcriorly.

‘lhese characters are corroborated from my own observations of specimens although the last character is here modified from Denison’s original wording “spinal plate reduced anteriorly and posteriorly” because it is difficult t o demonstrate the posterior reduction of this plate. ‘I’he anterior reduction of the spinal is confirmed by the more extensive contact area between the iriterolateral arid anterior lateral plates in these taxa, whereas typical Gogo ‘coccosteids’ show comparati\dy very short contact between these two plates. One feature Denison used to separate the Camuropiscidae from Zncisoscutum-the contact between the anterior lateral and anterior ventrolateral plates--is not found in Zdocamuru.r arid represents the presumed primitive condition for camuropiscids and othcr eubrachythoracids. The cheek of Incisosculum features reduced submarginal and postsuborbital elements which arc tightly connected behind the suborbital, a condition similar to that of camuropiscids but lacking firm suturing of the cheek u n i t t o the skull roof. Other striking similarities between ~ 7 ~ c ~ . s o , s c u ~ u ~ ~ and t,amuropiscids (but not necessarily synapomorphies) are the similar shape of the i tifi.rognathals in Incisosculum and juvenile C‘umuropiscis, and the same t 1 - x of scapulocoracoid ii.e. similar shape and same number of foramina in the articular crest i.

A deep postnasal plate participating in the orbital margin.

NEW AUSTRALIAN ARTHRODIRE 255

Latocamurus and other camuropiscids are more derived than Incisoscuturn in having:

(4) A broad rostral plate. Although the exact shape of the rostral plate differs i n the two specimens, in both it lacks an extensive posterior median lobe, a feature present on all T-shaped rostral plates of coccosteomorphs. Incisoscutum shows some variation in this plate, but the normal condition is to have a T-shaped rostral plate.

(5) A deep postnasal plate which participates in the orbital margin and excludes contact between the preorbital and suborbital plates. In Incisoscuturn the postnasal is comparably broad but does not exclude contact between the suborbital and preorbital plates.

(6) A suborbital plate which is firmly articulated to the postorbital plate. (7 ) The dentition is durophagous. (8) The submarginal and postsuborbital plates are strongly interconnected,

(9) The preorbital plates have short mesial contact with each other. (10) The postmarginal sensory-line canal is not present. ( 1 1 ) The main lateral-line has a ventral course on the anterior dorsolateral

Camuropiscis, Rolfosteus and Tubonasus are more derived than Latocarnurus in

(12) A pointed rostral plate. ( 1 3) The submarginal lacks an anterior lobe, instead being short and deep. ( 14) Elongated preorbitals having more extensive median contact. (15) Anterior lateral plates contacting the anterior ventrolaterals along an

Both Tubonasus and Rolfosteus are more derived than the previous species in

(16) Tubular rostral plates.

The recent discovery of a new advanced camuropiscid having a rostral plate like that of Camuropiscis concinnus but a cheek plate arrangement like Tubonasus

forming a posterior cheek unit behind the suborbital.

plate.

having:

extensive margin.

having:

Rolfosteus

Tubonasus

Camuropiscis

Latocamorus

Incsoscutum

Harrytmmbsm

Figurr 16. Cladograrn of suggested relationships betwccn a typical coccostcid iHnrrytoombsia), carnuropiscids and Zncisosrutum.

256 J. LONG

(in which the postsuborbital sutures with the marginal) suggcsts that the tubular rostra of Kolfosteus and Tubonasus could be independently derived. This problem will be considered in detail after the new form is described. 'The abovc character scheme is summarized in the cladogram (Fig. 16). It is rioted that not all of the above characters are unique to camuropiscids and Zncisoscutum within the whole of the Arthrodira, but most represent specializcd conditions within thc framework of higher eubrachythoracids. As monophyly of camuropiscids is easily demonstrated (character 5), the acquisition of all the other characters can be seen as specializations within the family Camuropiscidae, irrespective of thc fact that certain other arthrodires possess some of these characters.

(:Os(:LUSIONS

A IICW camuropiscid, Lntornrnurus coultfiardi gen. et sp. nov., is described from the Upper Devonian Gogo Formation, \.l"estern Australia, and thc famil)- Camuropiscidae Dennis & Miles, 1979b is redefined to include characters of the new genus. Lntocamurus is regarded as the primitive sister taxon to a l l othcr camuropiscids as it lacks contact between the anterior lateral arid antc'rior ventrolateral plates and does not have a projecting rostra1 plate. The cthnioid ossification of Lntocamurus shows the possible presence of a terrnirialis ncr\.c running into interperichondral space above the nasal capsules, and has tlir autopalatines fused to it. The parasphenoid of Latocnmurus is unusually deep arid narrow as in Tubonnsus, and is firmly attached to the ethmoid boric.. Carnuropiscids and Zncisosculum are closely related b y shared features of' tlic postnasal plate and cheek unit, as proposcd by Denison ( 1984).

h ( : K N 0 \ V L , E D ( ; E ~ ~ E S l S

The author acknowledges a Xational Research Fellowship-Queen Elizabeth I1 Award enabling this research to be undertaken at the University of b'estern ;\ustraiia. Fieldwork at Gogo in 1986 1987 was funded through the National Geographic Society grant Number 3364-86 and the Q E I1 Research Fund. I offer thanks to the following volunteer workers who assisted me at Gogo: &fr Chris Nelson, Miss Susan Creagh, Dr Richard Holst and Mr Terry Barnes, and t o hlr Jim Coulthard and M r 'Len Hill, Gogo Station, for permission to collect specimens. Professor Brian Gardiner (King's College, London) is thanked for his helpful comments on the work.

K E FE K E S c: ES

l)ESlSOS, K. H., 1984. Further ci)tisidcratioii o f the phylogeny and i1assific;rtion of thr orrlrr .\rtlirodir,i Pisccs: Placodermi I . Jou/nol UJ lhrtebrnle Pnleontologv, 4: 396 41 2.

I lESSIS-BKYi\S , K.. 1987. A 1 1 e ~ specks of castmariosteid artlirodirc [ Pisccs: Placodcrmi from ( h g o . ivcstcrri .\usttdi:i. ,'oo/ogglcn/ Jourr id nf the [,ili7/?f1n S o r i c ! ~ , 90: 1-64,

I)t:NSIS, K. 1). & XIILES, R. S.. 1979a. 21 srcwid cuhrach~tlioracici at-throdirr lroni (;ago, \ \ n t r r t i .\iistt-alia. <idogi(ol Jouinnl o j thr Linnrnn Socie!~~. 67: 1-9.

DESNIS . K. 1). & SI11,ES. R.S.. 1979h. Eubrachythoracid arthrodircs with tuhular rostra1 pldtcs from (hqc j , \Vrstrrti .liisct-alia. <oologir.ol Joitrnnl uf lhe Linnenn .Sorie!y. 67. 297-328.

DESSIS. K. 1). & 1 1 ILES. R. S., 1980. Nrw durophagous arthrodirc., froni Gogo, \Vrjtcrti . I i t \ t I ; i l i : i

;ou/o,qical ,j%urnnl c?f the DESNIS , K . D. & S11L R. S.. 1981. A pach)i)stci~moi-ph arthrodirr from Gogo. \Yestt.rri .Iiistr~ili,t

<oo/o,qicnl ,7orrrrinl 0J the I.innunn Socir!y, 73: 2 1 3 - 258.

neon Socirfy, 69: 43-85,

NEW AUS’I’RALIAN AR’I’HRODIRE 257

R L; 1‘482 A r~ i l i r .n l ty i l i t i i . i i iil . i t iliigriliii niili . I iiiiili-tiir-i: l’iiiiii (>lss<s. I Y i ~ ~ ~ + ~ i i i rral of the Linnean Society, 7.5: 1.53- 166.

I)F.NNIS-BRYAN, K. & MILES, R. S., 1989. k’urthrr eubrachythoracid arthrodirrs rrorri Gogo, M’estern Australia. zoological Journal of the Linneaii Society, 77: 145-1 73.

FOREY, P. L. & GARDINER. B. G., 1986. Observations on Ctenur~lln (Ptyctodontida) and the classificatiun (if placoderm fishes. zoological Journal of the Linnean Society, 86: 43-74.

GARDINER. B. G., 1973. Interrrlationships of trlrostotnes. In P. H. Grrenwood, R. S. Miles & C. l’nttrrson ( Eds), fn i~rr~la~ionships of Fishes: 105-35. London: Academir Press.

GARDINER, B. G., 1984. Thr rrlationship of palaroniscoid fishes, a rcvicw hascd on new spccimcns o f . t l i m i n and Moythomasia from the Upper Devonian of Western Australia. Bulletin of Ihe Brilish Museum (.Vatural H i s t o y ) , (;eology, 37: 173-427.

GARDINER, B. G. & BAR’I‘RAM, 4. W., 1977. ‘l’hr homologies of vrirtral rranial lissures in osteichthyans. Linnean Society Of London, Symjosinm Series, 4: 227-245.

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GROSS, W., 1932. Die Arthrodira Wildungrns. <;en/ogiJche und Palaeontolo~<ische Ahhandlungen, 19: 5-61. LONG, J . A., 1985. A new osteolepidid fish from the Upprr Dr\oriian Gogo Formation, \Vestern Australia.

Records of the M‘estern Australian MuJeum, 12: 35 1-366. LONG, J . A,, 1987a. A new dinichthyid fish (Placodermi; Arthrodira) from the Upper Devonian of \Vestrrn

Australia. with a discussion of dinirhthyid interrelationships. Records of the Western Austialian .2fuseirm, 13: 5 15-540.

LONG, J. A, , 1987b. Late Devonian fishes from the Gogo Formation, \Vestern Australia new discoveries. Search, 18: 203-205.

LONG, J. A,, 1988. New information in the arthrodire Tuboriasus from Gogo, LVes~ern Australia. MrrnoirJ (!/ the Asociat iun of A u ~ t r a l a ~ i a n Palaeontologists, 5. In prrss.

XIILES, R. S., 1971. T h e Holonematidae (placoderm fishes), a rrview based on new specimens of Holonema from the Lpper Devonian of It’estrrn Australia. Philosophical Transactions of the Rqal Sociey of London ( B ) , 263: 101-232.

\lILES. R. S., 1977. Dipnoan (lungfish) skulls and the relationships of the group: a study based on new sprcirs from the Devonian of Australia. zo:logical Journal of the Linnean Society, 61: 1-328.

Mll,F,S, K. S. & DENNIS, K. D., 1979. A primitive eubrachythoracid arthrodire from Gogo, Western Australia. zoological j‘ournal of the Linnean Sociely, 66: 3 1-62.

IfILES. R. S. & YOUNG, G. C., 1977. Placodrrm interrelationships reconsidered in the light of‘ new go, it’estern Australia. Linnean Society of London, Symposium Series, 4: 123-198. ’OLL, T. S., 1968. The placoderm fish CoctosteuJ cuspidahs Miller ex Agassiz from the

hliddlr Old Rcd Sandslone of Scotland. Part I . Descriptivr morphology. Transaclions of the Royal Soriely oJ Edinburgh. 67: 367-476.

PLAYFORD, P. E. & LOiYRY, D. C., 1966. Dcvoniari reef complexes of the Canning Basin, Western Australia. Bulletin oJthe Geological Suriipv of Il.Pstern Australia, 118: 1-150.

RI‘I‘CHIE, A, , 1985. Gogo fishes. In P. V. Rirh & G. Van Tets (Eds), X^adimakara: Extinct Barkboned Animals of ,Australia: 102-1U8, Pioneer Design Studios, Lilydale, Victoria.

KIXON, A. E., 1976. Fossil Animal Remains: their Preparation and CunJeraa/iun. London: Athlone Press. KOSEN, D. E. FOREY, P. L., GARDINER, B. G. & PATTERSON, C., 1981. Lunglishes, tetrapods,

palrontology and plesiomorphy. Bulletin of the American Museum of Natural History, 167: 163-275. SI‘ENSIO. E. A., 1963. Anatomical studies on the arthrodiran head. Part I . Preface, geological and

grographical distribution, the organization of the head in the Dolichothoraci, Coccosteomorphi and Pach) ostcomorphi. ‘I’axonomic appendix. k”ungliga Svenska ~blPnskapJcikademiens Handlingar, 9: 1-4 19.

‘I‘EICHERT, C., 1949. Obscrvations on the stratigraphy and palaeontology of the Devonian western portion of Kimberley Division, Western Australia. Bureau of Mineral Resources Report, Canberra, 2: 55pp.

YOUNG, G. C., 1980. A new Early Devonian placoderm from New South Wales, Australia, with a discussion of plaroderm phylogeny. Palaeontographica, 167A: 10-76.

YOCNG, G. C., 1984. Reconstruction of the jaws and braincase in the Devonian placoderm fish BothriolepzJ. I’nlnPontologv, 27: 635-66 I .

ADL .I L X\lV a o r att

A r .%

ABBREVIATIONS USED IN T H E FIGURES

anterior dorsolateral plate at l . ASg attachment area for anterior anterior lateral plate superognathal anlerior median ventral plate att.PRO attaclimrnt area for prrorbital

of cthmoid bone att.SO attachment area for suborbital articular plate anterior superognathal ;\up autopalatine

anterior orbital attachment surfare platr

:interior \entrolatcral plate bticcohypophysial for am in:^ Ixairi cavity

i.iiannel for doi-sal 2isprt.t of prrort)ital procrss o f nciirocraiiiuni c Iiiiiincl fool- dorsal aspect of aulir.i\ q a l process of ~icurocrai i iut~~ mibi osal ossilication nicdian I rist'i of parasphcnoid posterior crista of mrdian dorsal

\uIxiciiLii- crista rc~i~I:iI sc~isor)--linc canal groove opening for the eridol) niplidtic duct drlm~ssioiis on ventral surfice of rthmoid hoiic h r contact with aiitcrior superogiiathal rtlimoid (rhinocapsular) boric hrarnina i n ventral wall of cthmoid I10nc \ rntial stirficr ol ' thc ethninid hi-amina o t i vciitral surfiicr of parazpticnoid groo\ c OII ventral surfice o f cthmoid bonc

h r intcrnal carotid arteries aiitcrdtitcral groovr hctrc..ccn the cthnioid 2nd suborbital horrrs, p t~oI )~ ih l~ fur orbitori;isal artery and \(in groo\-c and foramen fir i t . buccalis fbramrn h r the optic nerve groo\ t' Tor posterior superognathal groo\ e for submarginal plate i~ilerog~iatlial I)oiic iiifraor1)ital scnsory--liiie c a n a l groo1.c in tcrolatcrd pla tr postpcctoral lamiria of postci-ioi \ ciitrol,itcral plate niain late-ral-line canal groin e ~raiisvcrsc ledge 011 parasphenoid lcitcrLtl groovc of cthmoid hone ni,trgiil,il pliitc rncdinii doi.saI platr mcntomrckrlian ossilication rniddlr pit-line gram e nirdi;iti process o n dorsal side (if

p;trasphcnoid possi l i l c myodolnc ~io tc l i liir incurrent n,i i - is n'isal capsulc t i ~ s a l cavity gt-oovc. fix 11. huccalis and vrssels nuch'll "late ovrr1.rp inargin Tor prcorhital p h t c o\ erlnp lamina for rostal platc o\-crlap iirra fbr suborbital plat(.

< cl1tl;II platc

I l l a t <,

groove on parasphenoid

OC

Olf

orb orb. il P P111,

011

pcc. f Pi 1'L PhfG FhfV I" PSC PP

P.P'

pr.dct PRO 1'KO.H pr.in

pr.pos

PSO

PTO pt.o. pr

pr0f

PSI:

1's p

[ J l . l i

PYL

K ri

Sc Set. s11 so soc

so.cr wr

Yd

SOa

SP sue.\

term th.pr t.l.gr

tri

tub vrrt v.l .hyp

\ .m .h )p

occipital sensory-line dndl ~ I . < K J \ c olfactory nerve ohtected riuchal area part of thr orbital margin Ibrarncn for orbital a1-tery:' pineal plate posterior dorsolatcrnl platr prctoral fcnstra pineal foramen posterior lateral plate posterior marginal plate posterior mcdidn \ rntral pl'itc postriasal plate paranuchal platt p s t r r i o r pit l ine g r w n c or posterior process on rthtrioid t i o w mcdisn posterior process on nuclial

dctrnt process of quadra t e preurbital platr prcorbital flange internasal process stipcrlieialis prchndur ri(m c '

postcrior process posterior wpcrognaihlil boiic postsuhorhital p la te parasphenoid bone postorbital plate \ rntral postocular process paired pits on visccr,tl surface o f

posterior vcntrolattral plate quadrate hone

ridge on vrntal surli ice of rthmo~tl bonr sclrrotii bones scapulocoracoid submargiual plat c suhorhital plate subobst;intic area of licadshicld supraorhital sensor! -line c;iiiiiI

groin e suborbital crista of suborbital plate oral pit-linr groovc spinal plate supraorbital vault tcrminalis ncrvc prc-endolymphatic thickrning tr;ins\-ersr lateral srow c on dursiil surface of parasphenoid triangular dcprcasion on p~istwttital platc rostra1 tubuli in eihmoid bone vcrtcbral r lrmrntc groove on parasphrtioid for l a t e r a l bi-anches of the hypophysial \rill 1i)ramc.n for rnrdiari hypophysi,rl

plate

nuchill plate

rostra1 plate

\ ('111