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.

The data matrix used for the phylogenetic analysis was originally presented by Liu & Abdala (2020). We introduce some modification deleting and adding some characters, changing wordings of characters and scorings. We add the scores of the new Chinese taxa Euchambersia liuyudongi and of Nothogomphodon sanjiaoensis. Modified, and deleted characters are presented in supplementary information file. The produce the matrix we used Mesquite (Maddison and Maddison, 2021). This matrix was transformed from Mesquite to a TNT matrix and the phylogenetic analysis was produced by TNT (Goloboff and Catalano, 2016).

Mesquite and TNT.Funding provided by: Chinese Academy of Sciences*Crossref Funder Registry ID: Award Number: XDB26000000 and 132311KYSB20190010