vertebrates Cuvier, 1812 - vertebrates
   Cohort Amniota Haeckel, 1866 see Clade Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988]
     Class "Reptilia" Linnaeus, 1758 - reptiles
       Subclass †Theropsida Seeley, 1896
         Order †Pelycosauria Cope, 1878 - pelycosaurs
           Suborder †Sphenacodontia Marsh, 1878 see Order Pelycosauria Cope, 1878
             1 Family †Sphenacodontidae Marsh, 1878