Black striped capuchin

The black-striped capuchin (Sapajus libidinosus), also known as the bearded capuchin, is a capuchin monkey from South America. It was the first non-ape primate in which tool usage was documented in the wild, as individuals have been seen cracking nuts by placing them on a stone "anvil" while hitting them with another large stone. Adaptations to carrying large stones and fruit include strengthened back and leg muscles that permit the monkey to walk on its hind legs while carrying stones. The black-striped capuchin has traditionally been considered a subspecies of the tufted capuchin. On the contrary, the southern population here included in S. libidinosus has sometimes been considered another species, Azaras's capuchin (S. cay) (syn. S. paraguayanus).

The black-striped capuchin is found in the Caatinga, Cerrado, and Pantanal of Brazil. Some confusion surrounds the taxon juruanus, here included as a subspecies of the black-striped capuchin. It has been considered to occur from the upper Juruá River east and south to Mato Grosso, or alternatively entirely restricted to the region near the upper Juruá River. In the latter case, its range would be surrounded by C. apella, leading to doubts over its true taxonomic status.

Groves (2005) recognizes four subspecies:

In 2011, Jessica Lynch Alfaro et al. proposed that the robust capuchins such (formerly the C. apella group) be placed in a separate genus, Sapajus, from the gracile capuchins (formerly the C. capucinus group), which retain the genus Cebus.