Acanthotoposaurus bremneri and the origin of the Triassic archosauromorph reptile fauna of South Africa

Acanthotoposaurus bremneri, an early diapsid reptile from the Upper Permian Dicynodon Assemblage Zone of the Beaufort Group in South Africa's Karoo Ba sin, is not an archosauromorph, but is a junior subjective synonym of Young ina capensis, the most common diapsid reptile known from South African Perm ian sediments. This re-identification eliminates archosauromorphs from the Permian of South Africa, and reduces the number of Palaeozoic members of th is group to two European taxa: Protorosaurus speneri and Archosaurus rossic us. Removal of Acanthotoposaurus from Archosauromorpha supports recent pala eobiogeographical ideas that the earliest Triassic fauna of South Africa's Lystrosaurus Assemblage Zone did not evolve in the Karoo Basin, but instead is the result of migration into the basin from other regions of Gondwana.