Heleosuchus an enigmatic diapsid reptile from the late permian or early triassic of southern africa
The primitive diapsid reptile Heleosuchus griesbachi, from the Late Permian or Early Triassic of southern Africa, is redescribed on the basis of a new cast made from the type specimen. Few diagnostic features of the skeleton are preserved, making it difficult to establish specific affinities. No characters are known that are uniquely shared with archosauromorphs. In common with lepidosauromorphs, but in contrast with stem diapsids, cervical vertebrae 3–5 are shorter than the anterior trunk vertebrae, and the transverse processes are relatively short. Heleosuchus may be a member of the Eosuchia or an otherwise unrecognized lineage of primitive lepidosauromorphs. The possibility that this specimen shows thyroid fenestration of the pelvis and a shortened and (or) hooked fifth metatarsal cannot be unequivocally established.