Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Reptilia Linnaeus, 1758 - reptiles
     Subclass †Synapsida Osborn, 1903 - synapsids see Class Synapsida Osborn, 1903
       Order †Therapsida Broom, 1905 see [unranked] Therapsida Broom, 1905
         Suborder †Eotitanosuchia (Boonstra, 1963)
           Family †Phthinosuchidae Efremov, 1954
             Genus †Phthinosuchus Efremov, 1954