Goeldi's monkey - Callimico goeldii

Found in the tropical rainforests of Bolivia, Brazil, Peru and Columbia, "Goeldi's monkey is a zoological puzzle. It is small and looks rather like a Tamarin and like them, has claws rather than nails on the fingers. But its teeth and skull shape are more like the bigger New World primates, such as Capucins. It is now thought to be in a separate group of primates, distantly related to both Tamarins and Capucins."