Black Langur

The Indochinese black langur is a poorly known Old World monkey native to Laos and adjacent Vietnam. It was originally described as a subspecies of a different langur, later found to belong to the Francois' langur group, and in 2001 it was recommended to treat it as a separate species. Except for its almost entirely black pelage, it resembles the other members of that group (Wikipedia, general species account).

It appears to be parapatric with the Hatinh langur, with signs of intergradation, and genetically the two are barely separable, which has led to suggestions that it may be a black morph of that taxon.