White-thighed Surili

The white-thighed surili, also called the pale-thighed langur or surili, is an Old World monkey that lives in trees in sub-montane forest. It is endemic to the Thai-Malay Peninsula, the Riau Archipelago and Sumatra, and is characterised by the white patches on the outside of its legs, which give it its name. Four subspecies are recognised: siamensis, cana, paenulata and rhionis; Sumatran animals are generally attributed to cana and can look different from the Malaysian form (Wikipedia, general species account).