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 Odontoceti Flower, 1867 - toothed whales see Parvorder Odontoceti Flower, 1867
                       01 Family †Kentriodontidae Slijper, 1936
                       02 Family †Squalodontidae Brandt, 1873 - shark-toothed dolphins
                       03 Family Platanistidae Gray, 1846 - river dolphins
                       04 Family Ziphiidae Gray, 1850 - beaked whales
                       05 Family Delphinidae Gray, 1821 - oceanic dolphins
                       06 Family †Rhabdosteidae Gill, 1871 see Family Eurhinodelphinidae Abel, 1901
                       07 Family †Albireonidae Barnes, 1984
                       08 Family †Acrodelphidae Abel, 1905 see Family Acrodelphinidae Abel, 1905, nom. dub.
                       09 Family Monodontidae Gray, 1821 - white whales
                       10 Family Phocaenidae see Family Phocoenidae Gray, 1825
                       11 Family Pontoporiidae Gray, 1870 - Franciscana, La Plata dolphin
                       12 Family Physeteridae Gray, 1821 - sperm whales
                       13 Family †Agorophiidae Abel, 1913