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. Callithrix differs from Callibella in these features, as well as in size, with Callithrix species being significantly larger. Callithrix species differ from the tamarins of the genus Saguinus in that Callithrix has enlarged mandibular incisor teeth the same size as the canine teeth which are used for gouging holes in trees to extract exudates.