Kingdom Animalia Linnaeus, 1758 - animals
   Phylum Craniata Linnaeus, 1758 see Subphylum Craniata auct.
     Class Mammalia Linnaeus, 1758 - mammals
       Subclass Theria Parker & Haswell, 1897
         Infraclass Placentalia Owen, 1837 see Cohort Placentalia Owen, 1837
           Order Perissodactyla Owen, 1848 - odd-toed ungulates
             Family Equidae Gray, 1821 - horses, zebras, and asses