The armour of the extinct reptiles of the genus Pareiasaurus / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1908
Catalogue details

Licence: In copyright

Credit: The armour of the extinct reptiles of the genus Pareiasaurus / 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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    G07 Therefore the restorations which show elevated scutes extending from the skull to the extremity of the tail, or three parallel rows of scutes on the back entirely separated, and those which show the body clustered over with rows or groups of scutes, are entirely imaginary, for the only evidence for the armour is the skeleton in the British Museum. Some writers in this country, and in Germany, have denied that any armour at all is present. The British Museum skeleton is sufficient evidence of its characteristics. If it had been more extensively developed over the body it is improbable that it would have escaped detection in the careful removal of the matrix during the two years that I watched the development of the skeleton ; and there is no reason to modify in any way the original description or figure. That evidence may now be added to by a short account of specimens of scutes already referred to (l.c. pp. 315, 346) as collected by Mr. J. van Renen, R.H., at Steenkamps Poort, south of Fraserberg. I had just collected the Pareiasaurus and was passing north, when this gentleman showed me a series of badly preserved bones collected as weathered, and invited me to select any example which might be necessary. I had no doubt they were Pareiasaurian, though the essential characteristic parts of the skeleton were not preserved. I accepted one caudal vertebra, and a series of nine scutes as giving evidence of armour, which I had not seen at that time. The scutes are free from matrix, vary greatly in size, and belong to a different species from P. baini, which I propose to indicate on the evidence of these scanty materials as Pareiasaurus steenkampensis. The scutes can only be supposed to have been arranged as in P. baini ; that is, in a single longitudinal row down the back, with lateral scutes directed transversely outward on each side from the union between each two successive scutes of the linear series. All the ossifications are irregular, and about half are broken (text-fig. 125). It is possible that all of those preserved belong to the median series only, for none show the curved convex forms of the lateral scutes of P. baini, and this difference may be a specific character. Four or five can be recog- nised as median by their elongated forms ; and the remainder may be median or lateral, if lateral scutes were present, as I think the evidence of the surface characters indicates. They are smooth on the under side, marked on the upper surface with a central conical blunt boss, from which numerous short grooves radiate irregularly to the margin, which is commonly thick and rough, as though the plates were imbedded in the skin. Behind the central boss, which is more or less flattened above, and less than half an inch in diameter, is a distinct pit nearly as wide, which is seen in half a dozen examples. The radiating ridges are more or less pitted, and all the surfaces, superior and inferior, are pierced with fine vascular markings. The largest plates are about 2 J inches long by 1] inch wide, and fully half an inch thick at the central boss. In form they are irregularly ovate; some appear to be trans- versely ovate and have the central boss less conspicuous. [3]