Cephalopachus bancanus

Horsfield's tarsier (Cephalopachus bancanus), also known as the western tarsier, is the only species of tarsier in the genus Cephalopachus. It occurs on Borneo, Sumatra and nearby islands and is, like other members of the group, entirely nocturnal. Although Horsfield's tarsier was usually placed in the genus Tarsius with all other living tarsiers, it is quite distinct from the Philippine tarsier and the various tarsiers of Sulawesi and nearby islands; therefore, scientists have placed it in a separate genus, Cephalopachus. The taxonomy of this species is in doubt, with some subspecies considered unsure. In fact, over 20 years few studies have been done on C. bancanus and a taxonomic revision based upon intensive and systematic field surveys is overdue. The IUCN believes that these subspecies should be treated as distinct and named as separate taxa until more definitive evidence is available. When splitting the species into its own genus, Colin Groves and Myron Shekelle recognized the natunensis population as a distinct subspecies.