Roosmalens' dwarf marmoset

The Roosmalens' dwarf marmoset (Mico humilis), also known as the black-crowned dwarf marmoset, is a small New World monkey native to the Amazon rainforest on the east bank of the lower Madeira River and the west bank of the Aripuanã River in Brazil, with the smallest distribution of any primate in Amazonia. It was first described in 1998, after Marc van Roosmalen, who in 1996 received a captive animal from a river trader, traced it to the region near Nova Olinda in southeastern Amazonas. It has sometimes been placed in the monotypic genus Callibella, but genetic analysis places it in Mico. Adults are 38 to 39 centimetres long including a tail of 22 to 24 centimetres and weigh 150 to 185 grams, which makes it the second smallest monkey after the pygmy marmoset. The crown is blackish, the bare face is pale pink, and it usually gives birth to a single baby rather than twins.