What is "merycoidodon"

Merycoidodon (" ruminating teeth") is an extinct genus of terrestrial herbivore of the family Merycoidodontidae, subfamily Merycoidodontinae ( oreodont), more popularly known by the name Oreodon ("hillock teeth") endemic to North America during the Late Eocene- Early Miocene subepochs (38—16.3 mya) existing for approximately .