Martins' Bare-faced Tamarin occurs in forests between rivers in northern Brazil. Fruit was the main food recorded for one wild group of a named subspecies.
The face is bare and black. The upper coat is a streaked mixture of buff, olive, and brown, with the forequarters more faded than the hindquarters.
In one S. m. martinsi group followed in Pará from 2013 to 2014, fruits made up about 85% of feeding records. The group ate more fruit in the rainy season and used more insects and exudates in the dry season.
An extinction-risk assessment has not been added yet.