Class Mammalia Linnaeus, 1758 - mammals Order Artiodactyla Owen, 1848 - even-toed ungulates see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997 Family Giraffidae Gray, 1821 - okapi and giraffe Genus Okapia Lankester, 1901 - okapi Okapia johnstoni (Sclater, 1901) - okapi