Nomascus leucogenys (Ogilby 1840)
[Hylobates] leucogenys Ogilby 1840, Proc. Zool. Soc. Lond., 1840: 20.
Type Locality: Laos, Muang Khi (Fooden, 1987).
Vernacular Names: Northern White-cheeked Gibbon.
Distribution: SW Yunnan (China) to 19°N in Vietnam and Laos.
Conservation: CITES – Appendix I; U.S. ESA and IUCN – Endangered.
Discussion: Separated from concolor by Dao (1983) and Ma and Wang (1986).