coelacanthus granulatus moythomas

446 J. A. Moy-Thomas and T. S. Westoll—

On the Permian Coelacanth, Coelacanthusgranulatus, Ag.

By J. A. MOY-THOMAS, M.A., University Museum, Oxford, andT. S. WESTOLL, B.SC, University College, London.

I. INTRODUCTION.

A LTHOUGH the Permian species of Coelacanth, Coelacanthus- ^ granulatus, has been known since 1829, and although manyauthors have described specimens of it, it has remained unfortunatelyone of the lesser known of all Coelacanths. Since C. granulatusis the genotype of Coelacanthus, and since all the Carboniferousand some Triassic species have been assigned to this genus, it issurprising that further description has not been forthcoming. One ofus (J. A. M. T.) has for some time been working on the CarboniferousCoelacanths, and it has been impossible to determine whether thesereally belong to the genus Coelacanthus. Accordingly it was hopedthat by re-examining all the available material a more diagnosticdescription might be given. In doing this the authors have onlybeen partly successful, as some of the most important genericcharacters—the dermal bones of the cheek and snout—were notpreserved in any of the material examined. However, sufficientdiagnostic characters have been provided by this research to dis-tinguish the Carboniferous forms from this Permian genus.

Another reason for the re-examination of C. granulatus is thatthe other author (T. S. W.) has recently been revising the Permianfishes of England. As it will still be some time before this workcan be published, it will be mutually convenient to write the presentnote.

During this work the authors have had to borrow and examinea great deal of material from various museums. They have examinedmaterial in the British Museum (Natural History), including thetypes of C. granulatus and " C. caudalis " ; in the Royal ScottishMuseum ; the Yorkshire Museum ; the Hancock Museum of New-castle-upon-Tyne ; the Staatssammlung of Munich, including thetypes of " C. hassiae " and " C. macrocephalus " ; and in the Sor-bonne. The authors would like to express here their gratitude toDr. E. I. White of the British Museum (Natural History), Dr. A. C.Stephen of Edinburgh, Dr. Collinge of York, Mr. T. Russell Goddardof Newcastle-upon-Tyne, Professor F. Broili of Munich, andProfessor M. Jacob of Paris for their kindness and generosity inlending material.

The authors are also indebted to Professor E. S. Goodrich andto Professor D. M. S. Watson for reading this manuscript and formany helpful suggestions. One of the authors (T. S. W.) isindebted to the Department of Scientific and Industrial Researchfor a Senior Research Award.

On Coelacanthus granulatus. 447

II. HISTORICAL NOTE.

The earliest mention of a Permian Coelacanth is by Sedgwick(1829), who figured an almost complete specimen and a separatepterygoquadrate from the Marl Slate, but did not name or describethem. Agassiz (1839) figured two caudal regions from the MarlSlate as Coelacanthus granulatus without description. Miinster(1842) described a specimen from the Kupferschiefer as C. hassiae.In 1844 Agassiz published the description of his figures under thename of C. granulosus. Egerton (1850) described two more Permianfishes, one as C. granulatus and the other as C. caudalis. Geinitz(1861) described a few bones, easily identifiable from his figures asthose of a Coelacanth, as Pygopterus humboldti. Huxley (1866) inhis review of the Coelacanths figured and described Egerton's typespecimen of C. caudalis anew. Willemoes-Suhm (1869) describedand figured a specimen as C. macrocephalus, and redescribed someof Miinster's types of C. hassiae. Reis (1888) suggested that C.macrocephalus is not distinct from C. hassiae, to our knowledge ofwhich species he added many valuable details and figures. Wood-ward and Sherborn (1890) suggested that C. caudalis is an immatureform of C. granulosus, and in 1891 Woodward classified all thepreviously described Permian species into the single species C.granulatus. This conclusion of Woodward's has been confirmed bythe authors beyond doubt after re-examination of all the types.Stensio (1932) defined the genus Coelacanthus, basing his definitionentirely on C. granulatus.

III. COELACANTHUS GRASULATVS AGASSIZ." Fossil Fish." Sedgwick (1829), p. 118, pi. xi, ix, fig. 3.Coelacanthus granulatus, Agassiz (1839), pi. lxii.Coelacanthus hassiae, Miinster (1842), p. 49.Coelacanthus granulosus, Agassiz (1844), p. 172.Coelacanthus granulatus, Egerton (1850), p. 235, pi. xxviii.*Coelacanthus caudalis, Egerton (1850), p. 236, pi. xxviii.Pygopterus humboldti, Geinitz (1861), pi. viii, figs. 1-3.Coelacanthus caudalis, Huxley (1866), pp. 14, 21, pi. v, fig. 5.Coelacanthus macrocephalus, Willemoes-Suhm (1869), p. 74, pi. xi, fig. 2.Coelacanthus hassiae, Willemoes-Suhm (1869), p. 76, pi. x, fig. 1 ; pi. xi, fig. 1.Coelacanthus macrocephalus, Reis (1888), p. 68.Coelacanthus hassiae, Reis (1888), p. 69, pi. iii, fig. 22 ; pi. iv, figs. 7,12,15,16,19Coelacanthus granulosus, Woodward & Sherborn (1890), pp. 39, 40.Coelacanthus granulatus, Woodward (1891), pp. 400-1.Coelacanthus granulatus, Stensio, 1921, p. 118.Coelacanthus granulatus, Stensio, 1932, p. 40.

Type.—Caudal region (British Museum (Natural History), 3338).Locality.—Marl Slate of Durham and Northumberland and

Kupferschiefer of Germany.

Description,(a) General Body Form.

The species varies from medium to large forms, in which thebody is moderately slender and the head measures one-fifth of

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On Coelacanlhus granulatus. 449

the total body-length. The pelvic fins lie slightly posteriorly to theanterior dorsal fin. The anal fin is almost opposite the posteriordorsal fin. The supplementary caudal fin is well marked butprobably rather small.

(b) The Head.The head was almost as broad as deep, unlike that of many

Coelacanths. The anterior bones of the skull roof are not preservedin any of the material at the disposal of the authors. Parts of thefrontals are present in one of the English specimens (B.M., 3340),

s.tem.

TEXT-FIG. 2.—Skull of Coelacanthus granulatus. x $. Mostly fromspecimen P 3340 in the British Museum (Natural History), e.sc. =extrascapulars. fr. = frontal, pa. = parietal, s.tem. = supratemporal.

and are somewhat longer than wide, but probably incomplete.The growth centre is laterally placed. The supraorbitals anddermosphenotics are badly preserved, but there is no doubt thatthe latter is separate from the frontals. The parietals are knownfrom several specimens and are elongated bones ; they are separatefrom the supratemporals, which are somewhat triangular bones

VOL. LXXII.—NO. X. 29


extending anteriorly to a point. The supratemporals bear laterallya very well-marked facet for the articulation with the antero-dorsalmargin of the opercular. There is a continuous internal flangeon the lateral margin of the supra temporal and parietal. Theextrascapulars are poorly represented but must have numberedabout six, and would seem to have been in contact with one another,and with the parietals and supratemporals. All the bones of theskull roof are sparsely ornamented with feebly marked tubercles.

Only the most obscure fragments of dermal bones of the cheek arevisible, but the lacrimo-jugal seems to have been well ossified.

The lower jaw was strongly ossified and consisted of an angular,splenial, dentary, coronoid (possibly more than one), and a pre-

m.pt.

au.pal.

p.vo

ang.

den

TEXT-FIG. 3.—Pterygoquadrate complex of Coelacanthus gramdalus from aspecimen in the Hancock Museum, Newcastle. X J. ang. = angular,au.pal. = autopalatine. cor. = coronoid. den. — dentary. d.pal. =dermal palatine. ec.pt. = ectopterygoid. gu. = gular. m.pt. = meta-pterygoid. pt. = pterygoid. p.vo. = prevomer. qu. = quadrat?.

articular, and in addition to these Meckel's cartilage was ossified atleast in the articular. The coronoid is an oblong bone externallyornamented with vertically elongated tubercles. The internalsurface of this bone is also ornamented with fine vertical striae.Anterior to the coronoid there are traces of small tooth-bearingbones which are probably additional coronoid elements as in Macro-poma (Watson, 1925). The other bones of the lower jaw are, asfar as can be determined, similar to those of other Coelacanths andcall for no further comment.


The neurocranium was comparatively well ossified, but unfortun-ately this region is only known in a recognizable condition froma single specimen in the Hancock Museum in Newcastle. The ethmo-sphenoid moiety is apparently represented by more than one ossifica-tion. The ethmoid region is strongly ossified but badly preservedin the known material, but it seems as though there were pairedossifications. The sphenoid portion is very well ossified and presentsseveral interesting features. The posterior face has a large hollow,on either side of the upper margin of which there is a " condyle ".Between these " condyles " and slightly anterior to the dorsalmargin of the hollow is a pair of tiny pits lying very close together.Antero-dorsally to this is a well-marked transverse groove. It israther difficult to interpret these structures. Immediately dorsalto this region is the ventral margin of the cavum cerebrate, which is

TEXT-FIG. 4.—Xeurocranium of Coelacanthus granulatus, from a specimenin the Hancock Museum, Newcastle. X 1. " eondyle " = condyle onbasisphenoid. pa. = parietal, psph. = parasphenoid. s.tera. = supra-temporal.

4 a.—Posterior view of basisphenoid of this specimen.

too mutilated for further description. Only a pair of well-markedantotic processes is visible. It seems fairly certain that the basi-pterygoid process was not developed. The otic region is dis-appointing, but considerable ossification can be seen.

The parasphenoid is a fairly slender spatulate bone, covered bynumerous closely set teeth. It is very closely connected with thebasisphenoid. The prevomer is a small bone bearing large conicalteeth. The autopalatine is a triangular bone applied to the outersurface of the pterygoid, which has a narrow anterior shank, butbecomes much broader posteriorly, and passes into the verystrong vertical shank which bears a pair of strong ridges on itsouter surface. These ridges are prolonged into short blunt points


dorsally. Only traces of the metapterygoid have been seen. Thequadrate is a large bone closely applied to but perfectly distinctfrom the pterygoid, and bears a large transverse condyle for thelower jaw. The dermopalatine is a small narrow bone bearingboth granular, and a few larger conical, teeth. The ectopterygoidis a small slender bone with large conical teeth.

TEXT-FIG. 5.—Urohyal of Coelacanthus granulatus from a specimen in theHancock Museum, Newcastle. X 1.

The branchial arches are always too crushed for any description.The urohyal is large and bears a strong median ventral grooveleading to the posterior cleft. It tapers anteriorly.

TEXT-FIG. 6.—Left operoulum of Coelacanthus granulatus. Internal view fromspecimen 43472 in the British Museum (Natural History). X f.

The opercular is a triangular bone somewhat deeper than it islong, its posterior margin presenting a sigmoid curve. It is coveredwith characteristic ornament of very sparse feeble tubercles. The

On Coelacanthns granulatus. 453

gular plate is about a quarter as broad as long, and has no ornamentpreserved in any of the material examined.

There is a series of small unornamented plates surrounding theeye ; these are usually termed sclerotic plates, but have been recentlyshown (Moy-Thomas, 1935) to be ornamented in some forms andtherefore, being superficial, cannot be strictly comparable to truesclerotic plates.

The distribution of the sensory canals in the bones of the skullroof is difficult to make out, and the rarity of material makes itinadvisable to prepare the system. So far as can be seen there isa canal passing through the lateral parts of the supratemporal andparietal. In the lower jaw the course of the mandibular canal isshown in several specimens ; the canal is rather wide and opens onthe posterior part of the angular by several wide pores. The canalis also visible in the splenial.

(c) Axial Skeleton.

The axial skeleton consists of about seventy vertebrae. Theneural arches are of the type usually found in Coelacanths, and thespines are short behind the head as far as the anterior dorsal fin.

TEXT-FIG. 7.—Axial skeleton of posterior abdominal region of Coelacanthusgranulatus, showing pleural ribs passing into haemal spines. FromMunich specimen A.S. 239. X 1.

The ventral elements of the more anterior segments are smallpaired ossifications somewhat triangular in shape, the basiventrals.Articulating with these are short free pleural ribs, which can beseen posteriorly to come gradually together at their distal ends andpass continuously into haemal arches. This fact is particularlyinteresting because Stensio (1932) has suggested that similar ribsin Laugia are dorsal ribs. The haemal arches and spines call for nospecial comment.

(d) Paired Fins and their Girdles.The pectoral girdle is of considerable interest, being well pre-

served. The supracleithrum is a small triangular bone with athickened ridge running to each angle on the internal face. The region

454 J. A. Moy-Thomas and T. S. Wesloll—

usually occupied by the cleithrum in other Coelacanths is in thisform occupied by two separate ossifications. The larger of theseforms the whole blade of the bone down to the backwardly pro-jecting angle and is then prolonged ventrally into a narrow anteriorshaft. Behind this lies the second ossification, which is an elongatedoval bone pointed at each end. This bone is entirely ventral to

s.cl.

e.cl.

TEXT-FIG. 8.—Pectoral girdle of Coelacanthus granulatus, mainly from Munichspecimens, cl. = cleithrum. clav. = clavicle, e.cl. — extracleithrum.s.cl. = supracleithrum. The arrow indicates the point of attachmentof the fin skeleton. X §.

the origin of the pectoral fin and therefore cannot be homologizedwith actinopterygian postcleithrum. It must, therefore, be a newossification which has so far not been described in other fishes, forwhich the name extracleithrum is proposed. The clavicle is a smallcurved pointed bone which meets the lower end of both cleithrumand extracleithrum. There are about sixteen lepidotrichia in the

TEXT-FIG. 9.—Pelvic bone of Coelacanthus granulatus from Munich specimenA.S. 138. x 2.

pectoral fin, jointed distally for about two-thirds of their length.The pelvic girdle has already been quite well figured by Reis

(1888, pi. 4, fig. 7). The small inaccuracies in his figure have beencorrected in Text-fig. 9. The two plates meet one another and


possibly overlap slightly in the middle line. The lepidotrichia ofthe pelvic fin are fifteen to sixteen in number and are jointed forabout half their length.

(e) Unpaired Fins.The internal skeleton of the anterior dorsal fin is generally an

oval bone with somewhat angular rounded outlines. The finconsists of from eleven to thirteen strong lepidotrichia which arejointed distally for about two-thirds of their length except in theanterior short rays.

TEXT-FIG. 10.—Anterior dorsal fin skeleton of Coelacanthus granulatus, slightlyrestored, from specimen P 3342 in the British Museum (NaturalHistory). X 1.

TEXT-FIG. 11 a.—Posterior dorsal fin skeleton of Coelacanthus granulatusfrom specimen 43426 in the British Museum (Natural History). X 2.

116.—Anal fin skeleton of specimen in the Hancock Museum, Newcastle. X 1.

The basal plate of the posterior dorsal fin has a slender antero-ventral process extending between the neural spines, and a broaderanterior process ; posteriorly the plate is produced into an anglewhich must represent some of the postero-ventral process of the basalplate of Laugia. The fin is considerably lobed, and has eighteento twenty rays, the larger of which are jointed for about half theirlength.

The internal skeleton of the anal fin is a small narrow plate lyingsome distance ventrally to the posterior ribs. The fin consists ofabout fifteen rays, the longer jointed for about half their length.

456 J. A. Moy-Thomas and T. S. Westoll-

In the caudal fin the radials articulate with the slightly expandeddistal ends of the neural and haemal spines, and distally bearstout lepidotrichia, except in the case of the most anterior two orthree. The lepidotrichia number about twenty above and twentybelow ; there is usually one more ray dorsally than ventrally.One or two anterior rays are unjointed, the remainder are distallysegmented for a little over half their length.

The supplementary caudal fin is rather small and consists ofabout twelve rays both dorsally and ventrally.

The lepidotrichia of all the fins show no trace of ornament.

(/) Squamation.The scales are fairly large and rather thin. The whole scale

(of the anterior flank) is a little longer than high. The exposed

TEXT-FIG. 12.—Scales of Coetacanthus granulatus from specimen P 3338 inthe British Museum (Natural History). X 2.

part of the scale is distinctly higher than long and is ornamented withnumerous well-marked slightly elongated tubercles. The scalescarrying the lateral line are obvious and must have been morestrongly ossified than the rest of the scales.(g) The Swim-bladder.

This is well marked and extends back behind the pelvic fins.

IV. SUMMARY.

The following diagnosis of the genus Coelacanthus can now begiven in a form comparable with that used by Stensio (1932,pp. 39-45).

Medium to large Coelacanths, moderately slender. Head one-fifth of total length, almost as broad as deep. Ethmosphenoid part


of neurocranium probably ossified in three parts, probably alsowith granular ossifications. Basisphenoid with antotic process,probably without distinct basipterygoid process. Otico-occipitalregion well ossified. Supratemporal separate from parietal, dermo-sphenotic separate from frontal. Unornamented " sclerotic plates ".Cheek not yet known. Pterygoid with long low anterior shank,broad vertical shank. Coronoid almost rectangular, stronglyornamented on both faces. Opercular large and triangular, theposterior margin sigmoidally curved. Palatal teeth granular,few conical teeth on prevomer, dermopalatines, and ectopterygoid.Ornament of head bones sparse feeble tubercles.

Ossified basiventral and short separate pleural ribs. Pectoralgirdle with cleithrum and a separate extracleithrum : pectoralfin not situated low down. Pelvic girdle of characteristic shape :pelvic fins situated just behind the anterior dorsal fin. Anteriordorsal fin arising from somewhat oval basal plate. Posterior dorsalfin arising from basal plate with long anterior and antero-ventralprocesses and trace of postero-ventral process. Basal plate of analfin a small narrow plate. Caudal fin well-developed with supple-mentary caudal fin. Lepidotrichia of all fins unjointed for somedistance proximally and always without ornament. Scales some-what longer than high, exposed part higher than long, ornamentedwith tubercles arranged somewhat rostrocaudally.

V. REFERENCES.

AGASSIZ, A., 1833-1844. " Recherches sur les Poissons Fossiles," Neuchatel.EGERTON, P. M. G., 1850. In W. King, " A monograph of the Permian fossils

of England," , Palaeoni. Soc, London.GEINITZ, J. B., 1861. " Dyas, etc.," Leipzig.HUXLEY, T. H., 1866. " Illustration of the structure of Crossopterygian

Ganoids. 2. Coelacanthini," Mem. Geol. Surv. Unit. King., Figs.and Desc. Brit. Org. Rent., dec. 12.

MOY-THOMAS, J. A., 1935. " The Coelacanth Fishes of Madagascar," GEOL.MAG., LXXII, 213.

MUNSTER, G., 1842. " Beschreibung einiger merkwiirdigen Fische, etc.,"Beitrage zur Petrefahten-Kunde, Bayreuth, vol. 5.

REIS, 0 . M., 1888. " Die Coelacanthinen mit besonderer Beriicksichtigung derim Weissen Jura Bayerns vorkommenden Arten," Palaeontographica,35, 1.

SEDGWICK, A., 1829. " On the geological relations and internal structure ofthe Magnesian Limestone, etc.," Trans. Geol. Soc, (2), 3, 37.

STENSIO, E. A., 1921. Triassic Fishes from Spitzbergen, pt. 1, Vienna.1932. " Triassic Fishes from East Greenland," Medd. om Gronland,

Ixxxiii, Nr. 3.WATSON, D. M. S., 1921. " On the Coelacanth Fish," Ann. Mag. Nat. Hist.,

(9), 8, 320.WILLEMOES-SUHM, R., 1869. " Ueber Coelacanthus und einige verwandte

Gattungen," Palaeontographica, 17, 73.WOODWARD, A. S., and SHERBORN, C. D., 1890. Catalogue of British Fossil

Vertebrata.WOODWARD, A. S., 1891. Catalogue of the Fossil Fishes in the British Museum,

pt. 2.

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coelacanthus granulatus moythomas