Current issue


June 2022
45-1
<< prev. next >>

Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual

Article Management

You must log in to submit or manage articles.

You do not have an account yet ? Sign up.


The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)
Frederik Spindler
Keywords: cranium; pelycosaur; Permian; therapsid origins

doi: 10.18563/pv.43.1.e1
 
  Abstract

    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


  Article infos

Published in Vol 43-1 (2020)

PDF