Hoolock Gibbon - Classification

Classification

The classification of this gibbon has changed several times in the past few years. Classically, all gibbons were classified in the genus Hylobates, with the exception of the siamang. After some studies, the genus was divided into three subgenera (including the siamang's Symphalangus), and then into four (recognizing Bunopithecus as the hoolock subgenus distinct from other gibbon subgenera). These four subgenera were elevated to full genus status. However, the type species for Bunopithecus is Bunopithecus sericus, an extinct gibbon or gibbon-like ape from Sichuan, China. Very recent investigations have shown the hoolocks are not closely related to B. sericus, so have been placed in their own genus, Hoolock. In the process, the two subspecies of hoolocks have been raised to species level.

The two species of hoolock are:

• Western hoolock gibbon, Hoolock hoolock
• Eastern hoolock gibbon, Hoolock leuconedys