Nomascus

Nomascus is a genus of gibbons in the family Hylobatidae and the second most species-rich gibbon genus, found from Yunnan province in southern China to southern Vietnam and Hainan Island. Once classified as a subgenus of Hylobates with all its species lumped as a single species, Hylobates concolor, it now comprises eight species, seven living and one extinct, whose members carry 52 chromosomes and range in coloration from solid black to beige or peach with black crown tufts. Every species in the genus is classified as endangered or critically endangered, with the eastern black crested gibbon, Nomascus nasutus, considered the most critically endangered ape species in the world.