The emblematic South African therocephalian Euchambersia in China: a new link in the dissemination of late Permian vertebrates in Pangea

Therapsids were widely distributed along Pangea in the late Permian. South Africa in Gondwana and Russia in Laurasia are acknowledged as the principal areas of record of tetrapod (including therapsids) of this age. Sustained recent field explorations increased the importance of Chinese late Permian faunas which also was strongly reflected in the discovery of new therapsids and, in particular, several therocephalians recovered from the Naobaogou Formation in Nei Mongol. Here we report a therocephalian from that unit identified as a new species of the emblematic South African akidnognathid therocephalian Euchambersia. The new species, E. liuyudongi, is represented by a well preserved skull and mandible showing a well-developed maxillary fossa and absence of postcanine teeth. This is the third akidnognathid recovered from the Naobaougou Formation, but in a twisted way, the two basal Chinese akidnognathids previously known were recovered from a younger unit of the formation than the derived E. luiyudongi. This is the first time that a same therocephalian genus is recorded in northern and southern continents, making the record of the Naobaougou Formation, a key component to understand the evolution of late Permian continental faunas in general and of akidnognathid therocephalians in particular.