Helohyidae

Helohyidae were a group of artiodactyl mammals. They were most prominent in the mid-to-upper Eocene (~50 to 39 million years ago).

Achaenodon is an extinct artiodactyl mammal belonging to the family Helohyidae. It lived in the mid-late Eocene (about 43-39 million years ago) and its fossil remains have been found in North America.