Callitrichids

Callitrichids are a diverse group of small New World primates in the family Callitrichidae, encompassing what are commonly known as marmosets and tamarins. They occupy tropical forests and woodland edges across Central and South America, and are among the smallest of the simians. Typical callitrichid anatomy includes a dental comb formed by the lower incisors and canines, and a tendency toward arboreal, highly social life. A notable ecological adaptation is their reliance on tree sap and gum as a major food source, supplemented by fruit and insects; several species gouge tree bark to access gum, a habit known as exudivory.

In social structure, callitrichids commonly live in small family groups that may include multiple adults. A defining feature is cooperative breeding: non-breeding group members contribute to the care of the young, and births are often twins, with both parents and helpers involved in infant care. Group composition and breeding patterns vary by species, with some lineages showing tighter pair bonds and others more fluid alliances.

Taxonomically, the group includes the genera Callithrix and Cebuella (the true marmosets), Mico and Callimico, and the tamarin lineages Saguinus and Leontopithecus (the lion tamarins). Some classifications place these genera in different subgroups, reflecting ongoing revisions in primate systematics.

Conservation concerns reflect widespread habitat loss and fragmentation; several species are listed as threatened or endangered. Captive breeding and reintroduction programs have aided some populations, but ongoing habitat protection is essential.