The Golden Lion Tamarin (Leontopithecus rosalia) is listed as endangered on the IUCN Red list. There are around 1,000 living in the wild and close to 500 in zoos and captive breeding programs worldwide. Deforestation is the major threat, as their original habitat has been reduced to less than 10% of its original area.
To learn more about the Golden Lion Tamarin go to:
http://animals.nationalgeographic.com/animals/mammals/golden-lion-tamarin/
http://www.arkive.org/golden-lion-tamarin/leontopithecus-rosalia/