Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Goodrich, 1930
         Amniota Haeckel, 1866 - 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