Oreopithecus, extinct genus of primates found as fossils in Late Miocene deposits in East Africa and Early Pliocene deposits in southern Europe (11.6 to 3.6 million years ago). Oreopithecus is best known from complete but crushed specimens found in coal deposits in Europe. The relation of the genus to other primates has been a matter of some debate and confusion; Oreopithecus appears to combine primitive and advanced features that, on one hand, seem to ally it with the Old World monkeys and, on the other, with the advanced, manlike apes. It is probable that Oreopithecus represents a specialized side branch of primate evolution that did not give rise to more advanced forms; it is generally included in a separate ape family, the Oreopithecidae. Oreopithecus, an inhabitant of swampy regions, was about 1.2 m (4 feet) tall and had long arms; it is estimated that Oreopithecus weighed about 40 kg (90 pounds). The skull was small and the teeth were specialized; it probably ate soft plant foods. It is doubtful that Oreopithecus habitually stood erect.