New World monkeys are the simian primates of the infraorder Platyrrhini, native to the Americas. They occur from southern Mexico through Central America into South America and nearby islands. For broader context see primates and for taxonomic overviews consult general resources via reference sites. Their range and diversity are summarized below; for regional checklists try regional databases.

Families and representative species

  • Callitrichidae (marmosets and tamarins) — small-bodied species, often twin-bearing. Examples: Callithrix jacchus (common marmoset), Saguinus imperator (emperor tamarin).
  • Cebidae (capuchins and squirrel monkeys) — intelligent, dexterous primates. Examples: Cebus capucinus (white-faced capuchin), Saimiri sciureus (common squirrel monkey).
  • Aotidae (owl monkeys or night monkeys) — typically nocturnal. Example: Aotus species (owl monkeys).
  • Pitheciidae (titis, sakis, uakaris) — seed- and fruit-specialists. Examples: Pithecia (sakis), Cacajao (uakaris).
  • Atelidae (howler, spider, woolly monkeys) — many have fully prehensile tails. Examples: Alouatta (howler monkeys), Ateles (spider monkeys).

These groups contain dozens of described species distributed among several genera. Some taxa have been recently reclassified as molecular studies refine relationships; names and species limits may change as research continues. For concise species lists consult taxonomic checklists or conservation databases via specialist portals.

Key characteristics that distinguish New World monkeys include broadly spaced, side-facing nostrils (hence "platyrrhine"), a dental formula that often differs from Old World monkeys, and in many species a prehensile tail used as a grasping limb. Most are arboreal and diurnal, with the exception of nocturnal owl monkeys. Body size ranges from very small marmosets to large howler and spider monkeys.

Evolutionary evidence suggests New World monkeys colonized South America tens of millions of years ago, then diversified into the families listed above. They play important ecological roles as seed dispersers, pollinators, and components of forest food webs. Many species face threats from habitat loss, hunting, and the illegal pet trade; conservation status varies by species and region. For conservation actions and species assessments see conservation resources.