Species within " Nomascus " are characterized by 52 chromosomes.
One species, " Nomascus nasutus, " has been deemed " the most critically endangered ape species in the world ".
For example, the highly endangered eastern black crested gibbon ( " Nomascus nasutus " ) replaced the Hainan black crested gibbon.
The Tonkin black crested gibbon ( " Nomascus concolor concolor " ) occurs in southern China ( southwestern Yunnan ) and northern Vietnam ( Red Rivers.
One thousand years ago, gibbons which may have been crested gibbons ( " Nomascus " ) were found over a large part of southern and central China up to the Yellow River.
It was formerly considered a subspecies of the eastern black crested gibbon ( " Nomascus nasutus " ) from Cao B?ng provinces of Vietnam and Jingxi County in Guangxi Zhuang Autonomous Region, China.
These include the globally vulnerable pig-tailed macaque, Assam macaque, stump-tailed macaque and white-cheeked crested gibbon ( " Nomascus leucogenys " and " Nomascus leucogenys siki " ).
These include the globally vulnerable pig-tailed macaque, Assam macaque, stump-tailed macaque and white-cheeked crested gibbon ( " Nomascus leucogenys " and " Nomascus leucogenys siki " ).
Since 2003 KFBG has been involved with conserving the Hainan gibbon ( " Nomascus hainanus " ), thought to be the rarest ape in the world, at its last refuge at Bawangling National Nature Reserve.
The Hainan black crested gibbon ( " Nomascus hainanus " ), which was removed from the 2008 2010 list, still has fewer than 20 individuals left, but significant efforts to protect it are now being made.