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 Artiodactyla Owen, 1848 - even-toed ungulates see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
                     Suborder Suina Gray, 1868
                       Superfamily †Entelodontoidea Lydekker, 1883
                         1 Family †Choeropotamidae Owen, 1845
                         2 Family †Cebochoeridae Lydekker, 1883
                         3 Family †Entelodontidae Lydekker, 1883
                         4 Family †Leptochoeridae Marsh, 1894 see Subfamily Leptochoerinae Marsh, 1894