Merycochoerus (Greek: "ruminant" (merux)-like "swine" (khoiros)) is an extinct genus of oreodont of the family Merycoidodontidae, endemic to North America. They lived during the Early Oligocene 33.9—30.8 mya, existing for approximately . Fossils are widespread through the western United States.
Merycochoerus was a cud-chewing plant-eater with a long face, tusk-like canine teeth, heavy body, long tail, short feet, and four-toed hooves. The long animals are thought to have been amphibious, as members of the genus possessed an elongated, barrel-shaped body and short limbs that are typical adaptations found in semi-aquatic mammals.
Species
M. carrikeri (syn. Promerycochoerus thomsoni) M. chelydra (syn. Promerycochoerus barbouri) M. magnus M. matthewi M. pinensis M. proprius M. superbus (syn. M. fricki, M. leidyi, M. macrostegus, M. montanus, M. temporalis, Promerycochoerus grandis, P. hatcheri, P. hollandi, P. inflatus, P. latidens, P. loomisi, P. lulli, P. marshi, P. microcephalus) M. vantasselensis