Taxonomic note: Bunopithecus: A genus-level taxon for the hoolock gibbon (Hylobates hoolock).

The recent discovery that the hoolock gibbon (Hylobates hoolock [Harlan, 1834]) has a karyotype distinct from all other hylobatids provides a new and strong motive for revising gibbon taxonomy and establishing hoolocks in a separate, higher taxon. Revising Groves's taxonomy of 1972, we propose that hoolock, along with the fossil species sericus, occupy a subgenus, Bunopithecus. With the newly added taxon, the genus Hylobates would thus contain four subgenera: Bunopithecus, Hylobates, Nomascus, and Symphalangus.