The northern buffed-cheeked gibbon resembles Nomascus gabriellae in appearance. Males and females of Nomascus annamensisdiffer in morphology and color. The male has a primarily black pelt that glistens silver in sunlight, with a lighter brown chest. The cheeks are a deep golden-orange, and the crest is very prominent. The female, on the other hand, lacks the characteristic crest and is orange-beige in color.
^ abThinh, Van Ngoc, Alan R. Mootnick, Vu Ngoc Thanh, Tilo Nadler and Christian Roos, Van Ngoc Thinh, Alan R. Mootnick, Vu Ngoc Thanh, Tilo Nadler and Christian Roos. "A new species of crested gibbon, from the central Annamite mountain range". Vietnamese Journal of Primatology. Vol 1. No. 4.