Hylobates muelleri Martin, 1841 . Nat. Hist. Mamm. Anim., p. 444.

TYPE LOCALITY: Indonesia, Kalimantan, "Southeast Borneo"; restricted by Lyon (1911:142) .

DISTRIBUTION: Borneo from the N bank of the Kapuas River clockwise around the island to the E bank of the Barito River.

STATUS: CITES - Appendix I; U.S. ESA - Endangered.

SYNONYMS: abbotti, funereus .

COMMENTS: Subgenus Hylobates . May be conspecific with H. agilis; a wide intergrade zone with H. agilis albibarbis in Borneo (Marshall and Sugardjito, 1986) .