Today, primates are split into two major suborders: Strepsirrhini (lemurs, galagos, lorises, and pottos) and Haplorhini (tarsiers, New World Monkeys, Old World Monkeys, and apes). The Haplorhini suborder is further divided into three parvorders: Catarrhini (Old World Monkeys and apes), Platyrrhini (New World Monkeys), and Tarsiiformes (tarsiers).
The catarrhines share the following distinctive features: downward facing nostrils, a lack of prehensile tail, flat fingernails and toenails, a tubular ectotympanic ear bone, eight premolars, and diurnal behavioral patterns. The catarrhine species are all native to either Africa or Asia.
