Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Mammalia Linnaeus, 1758 - mammals
             Theria Parker & Haswell, 1897
               †Trituberculata
                 †Symmetrodonta Simpson, 1925 see Infraclass Symmetrodonta Simpson, 1925
                   †Spalacotheriidae Marsh, 1887