Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Mammalia Linnaeus, 1758 - mammals
             1 Subclass Prototheria Gill, 1872 - monotremes
             2 Subclass †Allotheria Marsh, 1880 [monotypic]
             3 Subclass Theria Parker & Haswell, 1897
             4 Family †Didymoconidae Kretzoi, 1943, incertae sedis