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 Equus Linnaeus, 1758 see Equus caballus group Linnaeus, 1758
                               Equus (Equus) przewalskii Poliakov, 1881 see Equus caballus przewalskii Poliakov, 1881
                                 1 ‡Equus (Equus) przewalskii gmelini Antonius, 1912 see Equus caballus gmelini Antonius, 1912
                                 2 ‡Equus (Equus) przewalskii silvaticus Vetulani, 1928 see Equus caballus silvaticus Vetulani, 1928
                                 3 Equus (Equus) przewalskii przewalskii Poliakov, 1881 see Equus caballus przewalskii Poliakov, 1881
                                 4 Equus (Equus) przewalskii caballus Linnaeus, 1758 see Equus caballus caballus Linnaeus, 1758
                                 5 ‡Equus (Equus) przewalskii robustus Pomel, 1853 see Equus caballus robustus Pomel, 1853
                                 6 †Equus (Equus) przewalskii gracilis