Genus: Phthinosaurus EFREMOV, 1954
Etymology: Greek, phthino, "decline, wane" and Greek, sauros, "lizard": Declining lizard.

Species: borissiaki EFREMOV, 1954
Etymology:

Holotype: PIN 164/7

Locality: Belebei locality, Belebeiskii District, Bashkortostan (Bashkiry) Province, Western Cisuraly, European Russia.

Horizon: Biarmian Series, Belebey Formation, Zone II.

Biostratigraphy: Ocher Faunal Assemblage, Ocher Faunal Subassemblage, Zone II.

Age: Upper Kazanian substage, Capitanian Stage, Middle Zechstein Epoch, Late Middle Permian.

Material: Fragmentary dentary.

Referred material:

PIN 297/1, 297/2: Fragmentary lower jaws.

PIN 164/12: Scapula.

PIN 164/3: Ulna.

PIN 164/6: Angular.