A new species of basal rhynchosaur ( D iapsida: A rchosauromorpha) from the early M iddle T riassic of S outh A frica, and the early evolution of R hynchosauria

Rhynchosauria was an important clade of herbivorous archosauromorph reptiles during the T riassic, with a worldwide distribution. We describe a new genus and species of early rhynchosaur, Eohyosaurus wolvaardti gen. et sp. nov. , from the early M iddle T riassic (early A nisian) C ynognathus   A ssemblage Z one ( S ubzone B ) of the K aroo S upergroup, S outh A frica. E ohyosaurus wolvaardti is known from a single skull, and is recovered as the sister taxon of R hynchosauridae in a new phylogenetic analysis. C ynognathus   S ubzone B has previously yielded the stratigraphically oldest well‐understood rhynchosaur species, M esosuchus browni and H owesia browni . E ohyosaurus wolvaardti increases the rhynchosaur diversity within this stratigraphical horizon to three species. Intriguingly, all currently confirmed rhynchosaur occurrences from the E arly T riassic to earliest M iddle T riassic are from S outh A frica. This may suggest a relatively restricted palaeogeographical distribution for early rhynchosaurs, followed by a global dispersal of rhynchosaurids during the Middle Triassic. © 2015 The Linnean Society of London