Science Fair Project Encyclopedia
Hominidae Catarrhini is the unranked group of the Primates, one of the three major divisions of the suborder Haplorhini. It contains the family Cercopithecidae (Old World monkeys), the gibbons or lesser apes (Hylobatidae) and the Hominidae (hominids), which include humans, chimpanzees, gorillas, bonobos and orangutans. Some count the orangutan as its own family, called Pongidae. Older authors described humans and their most close extinct relatives/ancestors as family on its own and placed the great apes in the family Pongidae. The other haplorhines are the prosimian tarsiers, which were formerly classified as strepsirhines, and the Platyrrhini (New World monkeys), which live in South America.
Catarrhini means narrow nose, and the term describes their narrow, downward pointing nostrils. Unlike the platyrrhini, they are generally diurnal and their tails (if they have tails at all) are not prehensile. They have flat fingernails.
Their dental formula is
Classification and evolution
The apes and Old World monkeys split from their New World monkey kin about 40 million years ago. The major catarrhine division occurred about 25 mya, with the gibbons separating from the great apes and humans about 18 mya.
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