Sinophoneus

Sinophoneus is an extinct genus of carnivorous dinocephalian therapsid belonging to the family Anteosauridae. It lived 272 to 270 million years ago at the beginning of the Middle Permian (Lower Roadian) in what is now the Gansu Province in northern China. It is known by a skull of an adult individual (the holotype GMV1601), as well as by many skulls of juvenile specimens. The latter were first considered as belonging to a different animal, named Stenocybus, before being reinterpreted as immature Sinophoneus. Sinophoneus shows a combination of characters present in other anteosaurs. Its bulbous profile snout and external nostrils located in front of the canine are reminiscent of the basal anteosaur Archaeosyodon, while its massive transverse pterygoids processes with enlarged distal ends are more similar to the more derived anteosaurs Anteosaurus and Titanophoneus. First phylogenetic analyzes identified Sinophoneus as the most basal Anteosaurinae. A more recent analysis positioned it outside the Anteosaurinae and Syodontinae subclades, and recovers it as the most basal Anteosauridae.

==Description== The holotype of Sinophoneus is a somewhat dorsoventrally deformed skull measuring 32 cm in length from the tip of the snout to the occipital condyle and about 35 cm in total length to the posterior border of the squamosal. The upper part of the orbits is crushed, giving them an oval shape. They had to be originally circular. Most of the temporal arches are missing, as is the dentition of the upper jaws. The lower jaw is not preserved. The skull is mainly characterized by the presence of a median ridge starting between the eye sockets (where it is poorly developed) and extending to the tip of the snout (where it is more robust) which it protrudes beyond in dorsal view. The nostrils are smaller than in other anteosaurs. As in Archaeosyodon, the nostrils are entirely located in front of the upper canine whereas in other anteosaurs they are mainly located above or behind the canine. The snout profile is bulbous as in Archaeosyodon. The transverse processes of the pterygoids have a very enlarged distal end giving them a palmate morphology in ventral view as in Anteosaurus and Titanophoneus.