Ancodonta

Hippopotamidae is a family of stout, naked-skinned, and semiaquatic artiodactyl mammals, possessing three-chambered stomachs and walking on four toes on each foot. While they resemble pigs physiologically, their closest living relatives are the cetaceans. They are formally referred to as hippopotamids.

Anthracotheriidae is a paraphyletic family of extinct, hippopotamus-like artiodactyl ungulates related to hippopotamuses and whales. The oldest genus, Elomeryx, first appeared during the middle Eocene in Asia. They thrived in Africa and Eurasia, with a few species ultimately entering North America during the Oligocene. They died out in Europe and Africa during the Miocene, possibly due to a combination of climatic changes and competition with other artiodactyls, including pigs and hippopotamuses. The youngest genus, Merycopotamus, died out in Asia during the late Pliocene, possibly for the sam

Choeropotamidae, also known as Haplobunodontidae, are a family of extinct mammal herbivores, belonging to the artiodactyls. They lived between the lower/middle Eocene and lower Oligocene (about 48 - 30 million years ago) and their remains were found in Europe and Africa.

Amphirhagatherium is an extinct genus of artiodactyl that lived in Northern Europe during the late Eocene to Early Oligocene.

Ancodonta is an infraorder of artiodactyl ungulates including modern hippopotamus and all mammals closer to hippos than to cetaceans (whales). Ancodonts first appeared in the Middle Eocene, with some of the earliest representatives found in fossil deposits in Southeast Asia. Throughout their evolutionary history they have occupied different browsing and grazing niches in North America, Eurasia and Africa. The last continent is notable as they were among the first laurasiatherian mammals to have migrated to Africa from Europe, where they competed with the native afrothere herbivores for the sam