ABSTRACT
The New World monkeys, or platyrrhines, are anthropoid primates that live in the lushest, most biodiverse rainforests of the world, in South America. They are part of the haplorhine branch of primate evolution, together with tarsiers and catarrhines, the Old World monkeys, and apes that are the platyrrhines’ nearest relatives. All platyrrhines are arboreal. One genus, the owl monkey, is nocturnal. Ecologically, the three families have evolved distinctive diets and three size classes that enable differentiation in communities: large-bodied frugivore-folivores, medium-sized fruit-huskers and seedeaters, and small-to-medium-sized predaceous omnivorous frugivores. The locomotor and postural variety of New World monkeys is distinctive. Two lineages have each evolved a different type of prehensile tail, several genera developed leaping adaptations, some are specialized foot-hangers, and there is a small-bodied radiation that has claws for climbing and clinging. Other notable adaptations are the communal social groups that help care for young in marmosets and tamarins, which give birth to twins twice a year, and tool-using in the relatively large-brainedcapuchin monkeys.
