Karoo tupilakosaurid: a relict from Gondwana

A new temnospondyl,Thabanchuia oomiegen. et sp. nov., is described from three skulls and associated postcranial elements from the Early TriassicLystrosaurusZone of South Africa.T. oomieis the best-preserved member of the Tupilakosauridae, a temnospondyl taxon previously known only from disarticulated material from Russia and Greenland, but shown here to includeKourerpeton bradyi, an articulated specimen with no locality data but presumed to be from North America. Tupilakosaurids are the only Mesozoic survivors of the dvinosaurian radiation, the sister group to the archegosaurs of the Permian plus the stereospondyl clade. It is postulated that their occurrence in Russia, Greenland and North America represents a reinvasion from Gondwana, where they survived the Late Permian extinctions along with the stem of the stereospondyl clade.T. oomieis probably immature but, like other members of the dvinosaurian clade, was fully aquatic, had ossified ceratobranchials and most likely an increased number of vertebrae and reduced limbs. LikeTupilakosaurus, T. oomiehad diplospondylous centra.