Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Infraclass Eutheria Gill, 1872
       Cohort Ferungulata
         Superorder Mesaxonia (Marsh, 1884)
           Order Perissodactyla Owen, 1848 - odd-toed ungulates
             1 Suborder Hippomorpha Wood, 1937
             2 Suborder Ceratomorpha Wood, 1937
             3 Suborder †Ancylopoda Cope, 1889 see Superfamily Chalicotherioidea Gill, 1872