There is one family of mammals that contains only two species: the Okapi and which other?
Giraffidae Giraffidae The Giraffidae are a family of ruminant artiodactyl mammals that share a common ancestor with cervids and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant genera, the giraffe (one species of "Giraffa") and the okapi (the only known species of "Okapia"). Both are confined to sub-Saharan Africa: the giraffe to the open savannas, and the okapi to the dense rainforest of the Congo. The two genera look very different on first sight, but share a number of common features, including a long, dark-coloured tongue, lobed canine teeth, and horns covered
Okapi okapi before the Zoological Society of London that depicted its physical features with some clarity. Much confusion arose regarding the taxonomical status of this newly discovered animal. Sir Harry Johnston himself called it a "Helladotherium", or a relative of other extinct giraffids. Based on the description of the okapi by Pygmies, who referred to it as a "horse", Sclater named the species "Equus johnstoni". Subsequently, Lankester declared that the okapi represented an unknown genus of the Giraffidae, which he placed in its own genus, "Okapia", and assigned the name "Okapia johnstoni" to the species. In 1902, Swiss zoologist Charles Immanuel