First trematosaurid temnospondyl from the Lystrosaurus Assemblage Zone of South Africa and its biostratigraphic implications

Abstract

A large temnospondyl mandible from the Lystrosaurus Assemblage Zone (Early Triassic) of South Africa is referred to the higher-level taxon Trematosauridae. The mandible is remarkably similar to that described for Trematosaurus from the Middle Buntsandstein of Germany, a genus closely related to the South African Trematosuchus, for which the mandible is unknown. However, the mandible cannot be referred unequivocally to either of these taxa. Trematosuchus is considered to be restricted to the lowermost subzone of the overlying Cynognathus Assemblage Zone, which, based principally on the temnospondyl and therapsid fauna, is considered to be of Upper Olenekian age. The mandible described here extends back the range of the Trematosauridae to the underlying Lystrosaurus Assemblage Zone and argues against the long-held notion of a sharp palaeontological break between the faunas of the Lystrosaurus and Cynognathus Assemblage zones. It also supports the hypothesis that the Lystrosaurus Assemblage Zone extended up to the Upper Olenekian.

The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence

“…The stratigraphic position of the type and only specimen of Lacertulus bipes is not constrained beyond Permian–Triassic [80]. Whereas Carroll [10] considered Paliguana whitei [77] to be of uncertain Late Permian–Triassic age, Kitching [81] and Groenwald & Kitching [82] listed this species as derived from the Lystrosaurus Assemblage Zone of Early Triassic age (Induan–?Olenekian [83]–[85]). …”

Preliminary observations on the bone microstructure, growth patterns, and life habits of some Triassic temnospondyls from India

“…However, Laurin et al (2004) in a recent study on Paleozoic temnospondyls have shown that these animals were terrestrial, and were secondarily adapted to water. Moreover, Damiani et al (2000) and Damiani and Welman (2001) suggested that trematosaurids occupied varied ecological niches ranging from near shore regions to fluvial settings.…”

The Permian Extinction and the Tethys: An Exercise in Global Geology

“…The archosaurs (ruling reptiles) soon produced prodigious predators (Benton, 2004, fi g. 1.9) and the unassuming Lystrosauri disappeared, probably mostly into the bellies of the early archosaurs at the latest by late Olenekian time (Damiani et al, 2000). But the primitive archosaurs could not keep pace with their much more sophisticated cousins who dominated the world from the late Anisian onwards to the end of the Cretaceous.…”