(superorder Paraxonia, order Artiodactyla)
A family of large, primitive artiodactyls that were especially common in the middle Tertiary in the Old World. They were pig-like in general appearance. From the nature of the sediments in which they are fossilized, it seems that they were amphibious. This supports the view based on anatomical evidence that they were the ancestors of the hippopotami. They arose in the Eocene and became extinct in the Pleistocene.
Subjects: Zoology and Animal Sciences.