Named By: Efremov - 1954.
Classification: Chordata, Synapsida, Therapsida, Phthinosuchia, Phthinosuchidae.
Species: P. discors (type).
Size: Total length uncertain due to incomplete fossil material, although estimates often cite 1.5 meters long. Skull is about 20 centimetres long.
Known locations: Russia.
Time period: Capitanian of the Permian.
Fossil representation: Partial skull.
Although Phthinosuchus is only known from a partial skull its classification required quite a bit of thought. This is because while the skull is that of a therapsid, it also displays some distinctly synapsid features more typical of a sphenacodont (like Dimetrodon and Sphenacodon). It may be that Phthinosuchus represents what was a transitional form, although without the light of additional fossil material this find can not be appreciated in its full.