. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. ANNALS OF THE SOUTH AFRICAN MUSEUM Lystrosaurus platyceps Seeley (Figs 68, 69) Lystrosaurus {Mochlorhinus) platyceps Seeley, 1898. Lystrosaurus andersoni Broom, 1907. Type specimen: Albany Museum. Locality: Bethulie, Orange Free State. This species is apparently the most advanced of those species with smooth, Dicynodon-Vike skulls. The snout is relatively deeper than in either L. curvatus or L. bothai. In lateral view the anterior facial surface is only very slightly convex and the transition be
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. ANNALS OF THE SOUTH AFRICAN MUSEUM Lystrosaurus platyceps Seeley (Figs 68, 69) Lystrosaurus {Mochlorhinus) platyceps Seeley, 1898. Lystrosaurus andersoni Broom, 1907. Type specimen: Albany Museum. Locality: Bethulie, Orange Free State. This species is apparently the most advanced of those species with smooth, Dicynodon-Vike skulls. The snout is relatively deeper than in either L. curvatus or L. bothai. In lateral view the anterior facial surface is only very slightly convex and the transition between facial and frontal planes is more abrupt than in curvatus or bothai, although there is no ridge or angular, sharp division between the two planes. A feature of Lystrosaurus platyceps, setting it apart from L. curvatus, is the inclusion of the entire nasal within the premaxillary facial plane, suggesting that deepening of the snout, which involves the maxilla and premaxilla in L. curvatus, has proceeded to the extent of involving the nasal in L. platyceps. That this is probably not an age phenomenon is shown by the fact that the four specimens of L. platyceps examined ( 706 and ) were smaller than several specimens of L. curvatus investigated. Lystrosaurus andersoni is included here on account of its smooth skull roof and the inclusion of the nasals in the facial plane. Resemblances between L. platyceps, L. curvatus and the apparently inter- mediate L. bothai include the broad, approximately rectangular preparietal, the interdigitating frontonasal suture, the lack of a transverse frontonasal ridge and the absence of longitudinal ridges on the snout. These three species can also be regarded as primitive in that, while they display the specializations of. Fig. 68. Lystrosaurus platyceps. No. 706. Skull in lateral Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - color
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