Cranial morphology and taxonomy of South African Tapinocephalidae (Therapsida: Dinocephalia): the case of Avenantia and Riebeeckosaurus
Date
2013-12-18
Authors
Guven, Saniye
Rubidge, Bruce S.
Abdala, Fernando
Journal Title
Journal ISSN
Volume Title
Publisher
Evolutionary Studies Institute, University of the Witwatersrand
Abstract
Tapinocephalid dinocephalians comprise a large component of Middle Permian herbivorous tetrapod biodiversity and are significantly abundant in the Karoo rocks of SouthAfrica. In order to understand the effect of the alleged Middle Permian extinction in the terrestrial record of amniotes a clear understanding of the taxonomic diversity of this group is essential. The tapinocephalids Avenantia kruisvleiensis and Riebeeckosaurus longirostris have in the past been distinguished by a set of characters, including differences in the snout length which was previously interpreted as a key diagnostic character. Further preparation of the material attributed to these species shows that the purported distinguishing characters, such as snout length, low intertemporal crest, and surface thickening of the parietal represent postmortem deformation (including distortion and weathering) or can be interpreted as individual or ontogenetic variation. Accordingly A. kruisvleiensis is synonimized with R. longirostris.
Description
Keywords
herbivorous Dinocephalia, Tapinocephalidae, Tapinocephalus Assemblage Zone, Karoo Basin, South Africa