Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Bilateralia
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Mammalia Linnaeus, 1758 - mammals
               Subclass Eutheria Gill, 1872 see Infraclass Eutheria Gill, 1872
                 Superorder Mesaxonia (Marsh, 1884)
                   Order Perissodactyla Owen, 1848 - odd-toed ungulates
                     Suborder Hippomorpha Wood, 1937
                       Superfamily Equoidea (Gray, 1821) Hay, 1902 see Family Equidae Gray, 1821
                         Family Equidae Gray, 1821 - horses, zebras, and asses
                           Genus Equus Linnaeus, 1758 - horses, zebras, and asses
                             Subgenus Hemionus Stehlin & Graziosi, 1935 see Equus hemionus group Pallas, 1775
                               Equus (Hemionus) hemionus Pallas, 1775 - onager
                                 1 ‡Equus (Hemionus) hemionus anatoliensis
                                 2 Equus (Hemionus) hemionus hemippus Geoffroy, 1855
                                 3 Equus (Hemionus) hemionus onager Boddaert, 1785 - onager
                                 4 Equus (Hemionus) hemionus kulan (Groves & Mazák, 1967) - kulan
                                 5 Equus (Hemionus) hemionus hemionus Pallas, 1775
                                 6 Equus (Hemionus) hemionus khur Lesson, 1827
                                 7 Equus (Hemionus) hemionus kiang Moorcroft, 1841 - kiang see Equus kiang Moorcroft, 1841