On Protorosaurus speneri (Von Meyer) / by H.G. Seeley.

  • Harry Govier Seeley
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: On Protorosaurus speneri (Von Meyer) / by H.G. Seeley. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The metacarpus has the bones more nearly equal in length than the metatarsus ; three are fasciculated in the middle, and the inner and outer bones are shorter and more spread out laterally. From this discussion I conclude that Protorosaurus has no predominant affinity with any existing order of animals. Its cranial characters appear to separate it widely from other ordinal groups. If the strongest resemblance of the upper surface of the skull is with certain Nothosaurs, the dental characters separate it. The second strongest resemblance is probably with certain Jurassic Ornithosaurs. The vertebral column as a whole has much in common with Pterodactyles, more perhaps than with any other group, but the differences in the articulation of the ribs and the sacrum separate it. The pelvis is intermediate between that of Pterodactyles and Plesiosaurians or Nothosaurs. The hind-limb is in its proximal segments suggestive of Dinosaurs, and in its distal segments approximates to Lizards. The scapular arch is too imperfectly known to yield marked evidence of affinity. The fore-limb shows no striking differentiation. The animal is therefore of an ancient stock, and may have been derived from the group from which Ornithosaurs were developed. Hence I conclude that von Meyer was fully justified in regarding Protorosaurus as the type of a distinct order of Reptiles, for which the name Protorosauria may be conveniently used. Description of the Plates. PLATE 14. Figure of specimen in College of Surgeons (No. 308, natural size). Figs. 2-7. Cervical vertebrse : sa, transverse process of sacral vertebra ; f femur ; ji, fibula ; t, tibia ; a, dermal armour. PLATE 15. Enlargement of skull and details of the teeth. Fig. 1. n, nasal; f frontal; p, parietal; so, supra-occipital; pf, prefrontal ; pm, premaxillary ; s, ? sclerotic armature; q, quadrate bone ; pt, pterygoid bone; pi, palatine bone ; v, vomer ; d, dentary bone ; a, articular bone ; an, angular; s.an, surangular; sp, spleniate. Figs. 2, 3. Teeth in skull. Figs. 4, 5. Teeth on the pterygoid bone. Figs. 6, 7. Teeth on the vomerine bones. Figs. 8, 9, 10. Teeth in the lower jaw. The appearance of a fang in fig. 9 may result from the alveolar border rising above the base of the tooth. Fig. 11. Dermal armour. PLATE 16. Outline restoration of the skeleton of Protorosaurus reduced. The shoulder girdle is omitted. The restoration is based chiefly upon the Vienna specimen.
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