Permian origins of the Lystrosauridae (Therapsida: Dicynodontia)

New material referable to the dicynodont family Lystrosauridae from the Permian of southern Africa is described. Three lystrosaurid species are recognized in the upper Madumabisa Mudstone Formation of the Luangwa Basin, Zambia, of which two are new (Euptychognathus kingae, sp. nov. and Madumabisa opainion, gen. et sp. nov.). Another new taxon, Lystrosauravus bothae, gen. et sp. nov., is described from the Cistecephalus Assemblage Zone of the South African Beaufort Group. The range of Euptychognathus bathyrhynchus is expanded, with new records from Zambia and possibly Zimbabwe. The holotype of the supposed basally branching lystrosaurid Kwazulusaurus shakai is reinterpreted as a juvenile specimen of Lystrosaurus. Inclusion of the new lystrosaurid taxa in a phylogenetic analysis of anomodonts recovers Madumabisa as the sister-taxon to Euptychognathus and Lystrosauravus as the sister-taxon to Lystrosaurus. Madumabisa is a relatively abundant taxon in the uppermost levels of the Madumabisa Mudstone Formation, indicating that lystrosaurids were not uniformly rare prior to habitat disruption surrounding the Permo–Triassic mass extinction, when Lystrosaurus became a hyper-abundant component of terrestrial faunas. The general morphological similarity of the Permian lystrosaurids to Lystrosaurus itself indicates that the unusual cranial morphology of this group did not evolve in response to pressures associated with the mass extinction, but may have been preadaptations aiding its survival.