156 11. on Certain Drnosavrian VERTE~R~ from the CI~RTACEOVS of IND]X and the Isle of Wight. by R. LYD~XER, Esq., BA

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156 MR, 1~. ]~YDEKKER ON DINOSAURIAN VERT]~BR2E

11. On certain DrNosAvRIANVERTE~R~ from the CI~RTACEOVSof IND]X and the IsLE oF WIghT. By R. LYD~XER, ESq., B.A., F.G.S., &c. (Read January 12, 1887.)

IN the year 1877 I published ~ a preliminary description of certain Dinosaurian remains obtained from the Lameta group of the Jabalpur district of India, to which I applied the name of Titano- saurus indicus. The Lameta beds, it may be observed, have been usually referred to the ~Iiddle Cretaceous (Upper Greensand), but later observations indicate that they may be of somewhat newer age. The remains on which the genus was founded are preserved in the Indian Museum, Calcutta, and comprise an imperfect femur, and a considerable number of late caudal vertebrm, together with one imperfect vertebral centrum from an earlier part of the series. In a later memoir t I gave figures of some of the more important of these specimens, and came to the conclusion that the vertelor~e in- dicated two species, for the second of which I proposed the name of T. 131a~fordi, adding the proviso that this form might eventually turn out to be generically distinct from T. indic~s. Both these types of late caudal vertebra3 are characterized by their strongly proccelous centra, to the anterior half of which the anchylosed neural arch is confined; and in the one perfect specimen of T. indic~es the arch carries two well-marked processes, one of which is directed anteriorly and the other posteriorly. The pre- axial process is bifurcated anteriorly, and bears a pair of prezy- gapophysial facets ; while the hinder one, which (judging from the caudal vertebrm of the Sperm-Whale and of certain other Dinosaurs) I think includes the representative of the neural spine +, is single, and carries the postzygapophyses. In T. indicus the h~emal aspect of the bone presents two pairs of Y-shaped ridges, on the extremities of each of which are a pair of well-defined facets for the attachment of chevron-bones, which look directly downwards; while the centrum is relatively short, with its ha, real surface placed nearly at right angles to the lateral surfaces and characterized by its extreme lateral compression. In the form to which the name T. Blan]~ordi has been applied the centrum is larger and subcylindrical, and the ha~mal and lateral surfaces are not distinctly differentiated from one another, the ridges on the former surface are not present, and the facets for chevron-bones are either very indistinct or totally wanting. These two types of vertebrae appeared to me to come nearest to those of Cet~osaurus and the so-called Pelorosaurus of the )~'nglish * Ree. Geol. Surv. Ind. col. x. p. 38 (1877). One of the specimens had been previously described and figured (without name) in Falconer's 'Palmontological Memoirs,' col. i. p. 418, pl. xxxiv, figs. 3-5. t ' Palseontologia Indica' (Mere. Geol. Surv. Ind.), ser. 4, col. i. pt. 3, p. 20. pls. iv. & v. (1879). Many writers adopt a different view in describing analogous specimens. Downloaded from http://jgslegacy.lyellcollection.org/ at New Mexico State University on January 17, 2015

FROM II~DIA AND THE ISLE OF WI6~ttT, 157

Wealden, in which the eentra are amphiccelous ; and also to those of the much smaller Macrurosaurus ~ from the Cambridge Greensand, in which there is a slight precocious character in some parts of the series, and distinct facets for chevron-bones are wanting. Their extreme precocious character seemed~ however, so peculiar that at a later date t T thought myself justified in assigning Titanosaurus to a new family of the Sauropoda. Thus the matter stood till some few months ago, when ]~[r. W. Davies, of the British ]~useum, directed my attention to two vertebral eentra in the Collection under his charge, which had been obtained by the late mr. Fox from the Wealden clay of Brook in the Isle of Wight. These centra, as ]~[r. Davies pointed out to me, agree in general characters with those of Titanosaurus~ and almost certainly belonged to a closely allied form. The least imperfect of the two specimens, which is figured (with the neural arch restored) in the accompanying woodcut, comprises the whole of the

Caudal vertebra of a Dinosaur, with the neural arch restored; from th6 Wea]den of Brook, Isle of Wight. 89nat. size. British l~Iuseum (No. R. 151). centrum and the base of the anchylosed neural arch. The two extremities are somewhat rolled and water-worn, and have thereby lost somewhat of their original roundness ; but in general contour, as well as in size, in the form of the articular surfaces, in the position of the base of the neural arch, and the apparent absence of distinct facets for chevron-bones, this specimen agrees very closely with the centrum of Titanosaurus Blanfordi represented in pl. v. fig. 3 of the memoir in the ' Pala~ontologica Indica ' which has been already

* Seeley, Quart. Journ. Geol. See. vo]. xxxfi, p. 440 (1876). Pa]montologia Indica, ser. 4, re!. i. Introductory Observations, p. v (lss5). Downloaded from http://jgslegacy.lyellcollection.org/ at New Mexico State University on January 17, 2015

158 ~R. R. LYDEKKER ON DINOSAURIAN V]~RT]~R~. quoted. The eentrum is, however, more compressed in the English specimen, while the heemal and lateral surfaces are distinctly differeutiated from one another, and the former surface carries a pair of V-shaped ridges resembling those of T. indicus. The specimen is in fact very nearly intermediate in character between the figured vertebrm of T. Blanfordi and T. indicus. The abrasion of the rim of the articular cup shows that the internal structure of the bone is coarsely cancellous. The second specimen (No. R. 146 a) comprises the anterior half of the centrum of a slightly smaller vertebra, and has been but little rolled. This specimen shows on the ventral aspect the well-marked V-shaped ridges so well displayed in the type specimen of T. indicus*, but lacks the distinct chevron-facets of that form. We may then, I think, consider it most probable that the English specimens indicate the occurrence in the Wealden of a Dinosaur closely allied to Titanosaurus; and it now remains to consider whether, in the first place, they can be referred to any genus already described from those beds, and, in the second place, whether or not they should be regarded as generically identical with one or both of the Indian forms provisionally included in the above- mentioned genus. With regard to the first question, among the large Dinosaurs of the Wealden the caudal vertebrm of Iguanodon and its allies are of a totally different type from the present specimens; while equally different are those of Cetiosaurus (with which may be grouped the so-called Pelorosaurus), as well as those of Megalosaurus, in both of which genera the centra have either flattened or slightly hollowed articular surfaces. Turning, however, to the gigantic Ornithopsis, we find that the caudal vertebrm have not been hitherto known T, and there is accordingly a strong lorimd facie presumption that the specimens under consideration may belong to that genus. The nearest allies to Ornithopsis are certain North-American Dinosaurs included in Marsh's Sauropoda $, such as .Brontosaurus, Morosaurus, Camarasaur~s, Amphiceelias, &c. ; in these, while the precaudal vertebrm have cavities in the centrum like those of Orni- tho2sis , those of the caudal region are solid. Apparently in all the American forms the centra of the caudal vertebrm are amphictelous, while those of the cervical region are opisthocoelous; since, however, in some genera, such as Camarctsaurus w the dorsal vertebrae are opisthoceelous, like those of Ornithopsis, while in others, like Amphico~lias I], they are amphic~lous, there is apparently no reason why similar variations should not also occur in the caudal region of other members of the group. In Brontosaurus, where Palmontologia Indica, ser. 4, vol. i. pt. 3, pI. iv. fig. 1. * See Hulke, Quart. Journ. Geol. See. vol. xxxvi, p. 3[;. There apparently is no reason why the amphiccelian vertebrm there mentioned should not belong to Cetiosaurus, since they agree closely with the specimens from the Great Oolite figured in Phillips's ' Geology of Oxford.' See Marsh, 'Amer. Journ.' vol. xxiii, p. 83 (1882), and vol. xxvii, p. 167 (1884). w Prec. Amer. Phil. Soc., Dec. 21, 1877, p. 237. IJ Ibid. p. 243. Downloaded from http://jgslegacy.lyellcollection.org/ at New Mexico State University on January 17, 2015

FROM INDIA AND THE ISLE 01~ WIGHT. 159

the dorsal vertebrae are amphicoelous, Professor Marsh's v figure and description show that the hinder eaudals have neural arches of the precise type of those of Titanosaurus, while the form of the middle part of their centra is apparently very similar to that of the specimens under consideration. In Camarasaurus, again, the centra are laterally compressed as in Titanosaurus indicus, although the facets for the chevrons are less strongly marked. Gamarasaurus and Amphiccelias, it may be observed, are of Cretaceous, while Brontosaurus is of Jurassic age. The suborder Sauropoda is taken to include Cetiosaurus, which, although none of the vertebral eentra are hollowed, is evidently allied to Orni- tho2sis; while it is probable, judging from the structure of the caudal vertebrze, that Macrurosaurus should also be placed in the same division. There appears therefore to be at least a considerable degree of probability that the Wealden vertebrm may belong to Ornithot)sis ; and if they do not it is pretty certain that they do not belong to any other previously known English genus. With regard to the second question--/, e. whether these vertebra~, which may be provisionally referred to Ornitho2sis , are generically identical with one or both of the two forms described under the name of Titanosau~ts--there is far less possibility of arriving at present at any very satisfactory conclusion. It will~ however, be safe to say that if the characters which distinguish the vertebrae of Titanosaurus indicus from those of T. Blanfordi eventually prove to be of not more then specific value, then the English vertebrae might well be also generically identical, in which case Titqnosaurus should be merged in Ornithopsis. If, however, 0n the other hand, the vertebra~ described under the name of T. Blanfordi should turn out (as it is highly likely that they will) to be generically distinct from T. indicus, then there would also be very considerable probability that the Wealden specimens are likewise generically distinct from both the Indian forms, although their relationship appears nearest to the form called T. Blanfordi. Under these difficult circumstances the only prudent course is to consider that we have evidence in India and Europe of three apparently closely allied Dinosaurs clearly marked off from all other described forms by their strongly precocious later caudal vertebrm, and for the present to retain the generic name Tita~tosaurus for the type Indian species, to refer the Wealden form provisionally to Ornithopsis, and to leave.it open whether the form to which the name Titanosaurus B!anfordi has been applied is generically identical with one or other or even both of these forms, or whether it should form the type of a third genus i". In conclusion, it may be observed that the occurrence in the Amer. Journ. voI. xxvi. pl. i. (1883), and vol. xxi. p. 420 (1881). $ In my description of Titanosaurus I mentioned a larger vertebral centrum which I regarded as preeaudal and precocious. Since,however, similar vertebrm, which are opisthoecelous, occur at Brook, the two types may respectively belong to the early caudal region of the Indian and European Dinosaurs, as the Croeodilia and Macrurosaurusshow that the form of the articular surfaces of the centra may vary in different parts of the caudal region. Downloaded from http://jgslegacy.lyellcollection.org/ at New Mexico State University on January 17, 2015

160 MR. R. LYDEKKER 01~" DINOSAURIAN VERTEBR-~. higher Cretaceous of India of two species of Dinosaurs apparently closely allied to one from the lowest Cretaceous of :Europe seems to be another instance of the survival in India of allied or identical generic types to a date after they had disappeared from Europe. h somewhat similar instance is afforded by the occurrence of Mega- losaurus in the Arri~ilur group (white chalk) of Trichinopoly in Southern India *~that genus being mainly characteristic of the Wealden and Stonesfield Slate, although lingering on to the Maestricht beds t~and also by the oft-quoted Siwalik fauna. I may also observe that if the Wealdcn vertebrm really belong to Ornithopsis, then we shall have good evidence of the distinctness of that genus from the North-American Camaresaurus, with which it has been identified by some writers--a distinction which might, I think, justify the reference of the English genus, together with Titclnosclurus, to a separate ihmily, the Ornithopsidre. Finally, I may express a hope that the Officers of the Geological Survey of India will direct their attention to the acquisition, from the Lametas of Pisdura, of other remains of Dinosaurs which may include vertebrm of the precaudal region, and thus indicate the true relationship of Titanosaurus to Or~ithopsis.

DISCVSSlON. Prof. S~EL:EY regretted the absence of the Author. The vertebra on which Titanosaurus was founded had long been known in Eng- land, but was considered insufficient to enable the relations of the animal to be determined. The femur had not been figured. The characters of the vertebrae were insufficient to show that there was any affinity to Cetiosaurus, and _Pelorosaurus was only a species of Cetiosaurus. The speaker considered that the vertebrm from the Isle of Wight were also insuf~cient for identification. The facets supposed to be those for the attachment of chevron-bones looked for- ward and outward, so that it was very questionable whether they were facets at all. The affiliation to OrnithoTsis rested on insufficient evidence. There was more similarity with Me, crurosaurus, but the eentrum in that genus is cylindrical. Although a large portion of the caudal region of ~he vertebral column of Macrurosaurus was known, its affinities were very doubtful. Mr. HuL~ concurred with the Author in thinking that the close similarity of the Indian and the Isle-of-Wight vertebrm warranted the assumption of a generic, if not specific identity, lie had never (nor, he believed, had Mr. Fox) found these vertebrae in the beds hitherto yielding the remains of O~.nitTwTsis, and he was in- clined to regard their reference to this Dinosaur only as provisional, the view taken, he understood, by the Author.

* Pa?~eontologia Indlca, ser. 4, vol. i. pt. ~, p. 26. t Vide Seeley, Quart, ffourn. Geol, Soc. vol. xxxix, p. 2i6 (1883).