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
             Subclass Theria Parker & Haswell, 1897
               Theria of Metatherian-Eutherian grade
                 Infraclass Eutheria Gill, 1872
                   Order Cetacea Brisson, 1762 - whales, dolphins, and porpoises see Infraorder Cetacea Brisson, 1762
                     Suborder †Archaeoceti Flower, 1883 see Infraorder Archaeoceti Flower, 1883
                       1 Family †Protocetidae Stromer, 1908
                       2 Family †Basilosauridae Cope, 1868