Phylum Chordata Bateson, 1885 - chordates Subphylum Vertebrata Cuvier, 1812 - vertebrates Class Mammalia Linnaeus, 1758 - mammals Order Artiodactyla Owen, 1848 - even-toed ungulates see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997 Family †Protoceratidae Marsh, 1891