Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Mammalia Linnaeus, 1758 - mammals
     Subclass Theria Parker & Haswell, 1897
       Infraclass Eutheria Gill, 1872
         Cohort Epitheria McKenna, 1975
           Superorder Ungulata Linnaeus, 1766
             Order Artiodactyla Owen, 1848 - even-toed ungulates see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
               Suborder Tylopoda "Illiger, 1811"
                 Family †Merycoidodontidae Hay, 1902 see Subfamily Oreodontinae Leidy, 1869
                   Genus †Promerycochoerus Douglass, 1901
                     1 †Promerycochoerus superbus (Leidy, 1870)
                     2 †Promerycochoerus carrikeri (Peterson, 1907)