Callithrix is a genus of New World monkeys of the family Callitrichidae, the family containing marmosets and tamarins. The genus contains the Atlantic Forest marmosets. The genera Mico and Callibella were formerly considered a subgenus of the genus Callithrix. Callithrix differs from Mico in dental morphology and in geographic distribution — Callithrix species are distributed near the Atlantic coast of South America, while Mico species are distributed further inland.