Nomascus siki Delacour 1951
Nomascus siki Delacour 1951, Mammalia, 15: 122.
Type Locality: Vietnam, Thua Luu.
Vernacular Names: Southern White-cheeked Gibbon.
Distribution: C Vietnam and Laos, from 15°45’ to 20°N.
Conservation: CITES – Appendix I; U.S. ESA – Endangered; IUCN – Data Deficient as N. leucogenys siki .
Discussion: Separated from leucogenys and gabriellae by Groves (2001 c).