Labyrinthodont tooth from South Africa / by H.G. Seeley.

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

Licence: In copyright

Credit: Labyrinthodont tooth from South Africa / 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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    [.Extracted from the Geological Magazine, Decade Y, Vol. V, No. 528, June, 1908.] A LARGE LaBYRINTHODONT ToOTH FROM THE UPPER KaRROO Beds of Wonderboom, near Burghersdorp. By Professor H. G. Seeley, F.R.S., F.L.S., F.G.S., King’s College, London. (PLATE X.) THIS vomerine tooth was found by Dr. D. R. Kannemeyer when resident at Burghersdorp. It is the only evidence of the dentition of the animal known, and is interesting as being of much larger size than any Labyrinthodont teeth hitherto found in South Africa, though smaller than the large teeth of Mastodonsaurus giganteus from the Keuper of Wiirtemburg. Its presumed position on the palate is based upon the anchylosis of the tooth with a bone which shows a flat oblique suture at the base of the crown. This sutural surface is usual on vomerine teeth, and indicates that the tooth was directed downward, outward, and a little backward. The base of the crown is closed and convex, and appears to be formed of dense tooth substance in which a labyrinthic structure is visible. On one side of the base there is a smooth surface, convex from above downward, concave from side to side, which is imperfectly preserved. This surface extends on to the palate, and is an indication of a vacuity, situated probably beneath an anterior nasal aperture. The bone about the base of the tooth projects all round it as a slight collar. The tooth is broken transversely, 1 £ inch of the length of the crown is preserved in front, and little more than one inch on the hinder border. The total length to the base is about 2 inches. This may indicate, by approximation of the lateral curvatures, an original length of 2£ inches. The base is transversely ovate, rather wider in front than behind, and rather more convex on the outer than on the inner side. But this irregular sub-triangular ovoid form is soon lost, and at the superior fracture the tooth is circular, with a diameter of more than half an inch. The external surface is marked with close-set fine linear ribs, which are flattened and have a tendency to be gathered into bundles, by the grooves from time to time becoming deeper, especially in