The Rio Acarí marmoset is a small monkey from the southern Brazilian Amazon. Bright orange patches stand out against much of its white upper coat, while its wild behavior and diet remain poorly studied.
Bright orange fur covers the lower back, underparts, legs, and base of the tail; the rest of the tail is black. Most of the upper body is white, with a white chest contrasting with black markings on part of the muzzle, the triangular nose patch, and the eye rings.
Detailed studies of its wild behavior and diet are not yet available. A 2007 field report recorded groups at three sites along the Sucundurí River.
An extinction-risk assessment has not been added yet.