Lesson’s saddle-back tamarin lives in lowland forest from southeastern Colombia to northwestern Brazil. It has a black head and face, a reddish throat and belly, and a mottled back.
The head, face, and crown are black; the throat, chest, and belly are reddish. Tan and black hairs create a mottled pattern across the back, rump, arms, and legs, and the tail is black.
It inhabits lowland forest between the Japurá/Caquetá and Içá/Putumayo river systems. The EAZA account names both primary and secondary forest.
An extinction-risk assessment has not been added yet.