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 Perissodactyla Owen, 1848 - odd-toed ungulates
               Suborder Hippomorpha Wood, 1937
                 Family †Brontotheriidae Marsh, 1873
                   1 Genus †Brontops Marsh, 1887
                   2 Genus †Brontotherium Marsh, 1873
                   3 Genus †Dolichorhinus Hatcher, 1895 see Genus Sphenocoelus Osborn, 1895
                   4 Genus †Embolotherium Osborn, 1929
                   5 Genus †Eotitanops Osborn, 1907 see Genus Palaeosyops Leidy, 1870