Cranial osteology of A rctognathus curvimola , a short‐snouted gorgonopsian from the L ate P ermian of S outh A frica

Gorgonopsia is one of the major clades of nonmammalian therapsids and includes the dominant vertebrate predators of the L ate P ermian. Unfortunately, gorgonopsian taxonomy is extremely problematic, due in large part to the lack of thorough descriptions and clear differential diagnoses for most nominal species. Here, the S outh A frican gorgonopsian species A rctognathus curvimola is redescribed based on a well‐preserved skull. Autapomorphies identified for A .  curvimola include a characteristic curvature to the alveolar margin of the snout, extremely reduced lacrimal, lengthy upper postcanine tooth row and a unique vomerine morphology. The nominal gorgonopsian species A rctognathoides breviceps and L ycaenodontoides bathyrhinus are considered junior synonyms of A .  curvimola . Other referred species of A rctognathus ( A .  whaitsi , A .?  cookei and A .?  nasuta ) share no unique characters with A .  curvimola and are removed from the genus; their generic placement is uncertain at present. Previous reports of A rctognathus from T anzania and the Middle Permian of South Africa are not referable to this taxon. At present, definitive specimens of A .  curvimola are restricted to the Upper Permian Cistecephalus and Dicynodon assemblage zones of South Africa.