Oreopithecus (ôr'ēōpĭth`əkəs, –pĭthē`kəs), extinct genus of apes whose fossils have been found in E Africa and Italy. It is best known through specimens preserved in coal deposits. It lived in swampy areas, was herbivorous, and had long arms. It has some similarities to later ancestors of humans, probably as a result of parallel evolution. Although related to predecessors of modern apes and humans, it is generally classed in a family by itself.