A new dicynodont (Anomodontia: Emydopoidea) from the terminal Permian of KwaZulu-Natal, South Africa
Date
2019-04
Authors
Kammerer, Christian F.
Journal Title
Journal ISSN
Volume Title
Publisher
Evolutionary Studies Institute
Abstract
A new taxon of dicynodont (Thliptosaurus imperforatus gen. et sp. nov.) is described based on a dorsoventrally-crushed skull from latest
Permian (upper Daptocephalus Assemblage Zone) strata in KwaZulu-Natal, South Africa. Thliptosaurus is distinguished from all other
dicynodonts by an elongate intertemporal bar with broad dorsal exposure of the parietals but apparently no pineal foramen. Absence of
the pineal foramen in dicynodonts is exceedingly rare; the only other taxa which exhibit this feature either have substantially broader
(Kawingasaurus fossilis) or narrower (Kombuisia frerensis) intertemporal regions. Inclusion of Thliptosaurus in a phylogenetic analysis of
dicynodonts recovers it as a kingoriid emydopoid, a position supported by its anteriorly-restricted pterygoid keel, elongate, curved
anterior process of the lacrimal, relatively posterior position of the median pterygoid plate, and occlusion of the mandibular fenestra by
a lateral plate of the dentary. Intriguingly, even in the other kingoriids which retain a pineal foramen (Dicynodontoides spp. and
Kombuisia antarctica), this structure is reduced in size relative to other dicynodonts, suggesting that the pineal eye was less important
for thermoregulatory activity in this clade than in other anomodonts. Although part of a local fauna including taxa that are otherwise
widespread in the Karoo Basin (Daptocephalus, Lystrosaurus), the unique presence of Thliptosaurus in the relatively poorly-sampled
Daptocephalus Assemblage Zone deposits of KwaZulu-Natal suggests that this region may preserve endemic taxa, and should be
prioritized for future fieldwork.
Description
Keywords
Synapsida, Dicynodontia, Permian, end-Permian mass extinction, South Africa