Roosmalens' dwarf marmoset (
Callibella humilis or
Callithrix (Calibella) 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. It has the smallest distribution of any primate in Amazonia. This
marmoset has several unique attributes, which has resulted in it being placed in the
monotypic genus Callibella.