Presbytis percura
Range
East-central Sumatra
On Sumatra the banded surili is the East Sumatran banded langur, Presbytis percura. It was long treated as a subspecies of Raffles' banded langur (P. femoralis), but genetic work led to it being recognised as a full species, and P. femoralis is now restricted to Singapore and southern peninsular Malaysia (Wikipedia, general species account).
It is found in east-central Sumatra and, like other surilis, is threatened mainly by habitat loss. Older field guides and checklists list the Sumatran banded form under the name femoralis.