Print ISSN: 0031-0247
Online ISSN: 2274-0333
Les traces de pas de Dinosaures et autres Archosaures du Lias inférieur des grands Causses, Sud de la France
Field trip guides/EAVP Annual Conference/2023
Les traces de pas d'amphibiens, de dinosaures et autres reptiles du Mesozoïque Français
Hypoplasia: CT-scan or naked eye?
Werneburg et al. New Permian Caseid from France
The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)cranium; pelycosaur; Permian; therapsid origins
Tetraceratops insignis is known from a single, crushed skull from the Lower Permian of Texas. Its unique proportions and osteological details gained central meaning in the question of the origins of Therapsida since this early synapsid has been determined as the oldest and less derived therapsid. Apart from Tetraceratops, the ‘mammal-like’ Therapsida and their sister, the pelycosaur-grade Sphenacodontidae, are separated by one of the longest ghost lineages in tetrapod fossil record. However, the minor, though well justified critique faced insistent publication regarding the therapsid hypothesis. A carefull re-evaluation of the holotypic skull reveals that therapsid traits cannot be supported, including a rejection of the formerly supposed adductor shelf in the temporal fenestra. Increased understanding of ‘pelycosaur’ character variation underlines a haptodontine-grade or, less likely, sphenacodontid position for Tetraceratops.
Published in Vol 43-1 (2020)