Cercopithecidae
Old World monkey is the common English name for a family of primates known taxonomically as the Cercopithecidae . Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons (genus "Papio") and macaques (genus "Macaca"). Common names for other Old World monkeys include the talapoin, guenon, colobus, douc (douc langur, genus "Pygathrix"), vervet, gelada, mangabey (a group of genera), langur, mandrill, surili ("Presbytis"), patas, and proboscis monkey. Phylogenetically, they are more closely related to apes than to New World monkeys. They diverged from a common ancestor of New World monkeys around 45 to 55 million years ago.