Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Infraclass Eutheria Gill, 1872
       Magnorder Boreoeutheria Springer & de Jong, 2001
         Superorder Laurasiatheria Waddell, Okada & Hasegawa, 1999
           Order Perissodactyla Owen, 1848 - odd-toed ungulates
             Suborder Hippomorpha Wood, 1937 [monotypic]
               1 Family Equidae Gray, 1821 - horses, zebras, and asses