living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Mammalia Linnaeus, 1758 - mammals
               Subclass Theria Parker & Haswell, 1897
                 Infraclass Eutheria Gill, 1872
                   Order Perissodactyla Owen, 1848 - odd-toed ungulates
                     Family Equidae Gray, 1821 - horses, zebras, and asses
                       Genus Equus Linnaeus, 1758 - horses, zebras, and asses
                         1 Equus caballus Linnaeus, 1758 - horse
                         2 Equus africanus (Fitzinger, 1857) - African ass see Equus asinus africanus Heuglin & Fitzinger, 1866
                         3 Equus asinus Linnaeus, 1758 - ass
                         4 Equus hemionus Pallas, 1775 - onager
                         5 Equus grevyi Oustalet, 1882 - Grévy's zebra
                         6 Equus burchelli (Gray, 1824) see Equus burchellii (Gray, 1824)
                         7 Equus zebra Linnaeus, 1758 - mountain zebra
                         8 ‡Equus quagga Boddaert, 1785 - quagga