On Hortalotarsus skirtopodus, a new saurischian fossil from Barkly East, Cape Colony / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: On Hortalotarsus skirtopodus, a new saurischian fossil from Barkly East, Cape Colony / 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.

    6/12 (page 414)
    well ossified and well rounded from back to front, and concave on the hinder margin in the usual way between the condyles, though the right condyle is not preserved. The tibia and fibula are in natural association, but the proximal articular end of the fibula is lost, and the proximal end of the tibia is slightly broken. Both bones have large central cavities, like Palceosaurus and the allied Triassic reptiles of Europe. The tibia (fig. 2) is inches long. The transverse width of its distal end is 1^ inch. The width at the proximal end is 1TV inch as preserved, but may have been slightly more. The antero-posterior measurement at the proximal end is 2^ inches and at the distal end is ^ inch. Thus the two ends of the bone have the aspect of being twisted nearly at right angles to each other, as in many other Dinosaurs. In general form and size the bone resembles Agrosaurus, and, in a less degree, Palceosaurus. The proximal articular surface is flat, truncate, slightly inclined backward and slightly inclined outward. It appears to have been subtriangular, wide behind, with a slight notch between the condyloid eminences on the posterior surface. The internal contour of the articulation was rounded from behind forward to the cnemial crest, which is small, rounded in front, and defined by a slight shallow fibular groove placed anteriorly, posterior to which was the large condyle on the external or fibular side. Seen from the internal aspect the anterior vertical contour of the bone is nearly straight, being very slightly concave; but the posterior contour is concave in its proximal third, owing to the backward extension of the condyles, and then straight almost to the distal end ; the bone has an aspect of being compressed from front to back in the lower part of the shalt. If there is an appearance of slight distal expansion, it is due to the way in which the metatarsal bones are crushed upon the tibia in front. On the posterior aspect the shaft contracts above the middle length to about T0y inch. It is well rounded from side to side in the middle, but flatter towards the distal end. Both inner and outer contours are concave in length, but the concavity at the distal end is only marked on the fibular side. This is due partly to crushing and partly to extension of the bone towards the fibula. If there is any notch on the distal fibular border of the tibia it is not exposed. There does not appear to be any notch or groove on the anterior side at the distal end, the condition of the bone in this respect resembling the tibia of Euskelesaurus. The absence of the distal notch on the tibia is a distinction from all known allies in the Trias of Europe.