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 †Pelycosauria Cope, 1878 - pelycosaurs
         Family †Sphenacodontidae Marsh, 1878
           1 Genus †Sphenacodon Marsh, 1878
           2 Genus †Dimetrodon Cope, 1878, nom. cons.