DistributionRead full entry
Range DescriptionThis species occurs in Indonesia (eastern Sumatra and the Riau Archipelago in the Strait of Malacca), Peninsular Malaysia, and extreme southern peninsular Thailand. It is found throughout the Malay Peninsula except for the south and northwest. In Sumatra, it occurs in a few small sections of the eastern forests (between the Siak and Inderagiri Rivers, between the Rokan and Barimun Rivers, the Lake Toba region, and perhaps the Jambi district); in the Riau Archipelago it is found on Kundar, Bintang, and probably Batam and Galang Islands. Population isolates are known within the range of P. femoralis in Thailand and P. melalophos in Sumatra (Groves 2001).
Presbytis siamensis siamensis
Occurs in Malaysia and Thailand. Found in most of Peninsular Malaysia except for the south and northwest (Perak north to the Piah Valley; Selangor; Negri Sembilan; Pahang; Melaka), with a population isolate reported in Thailand at 6°22'N, 101°08'E within the range of P. femoralis robinsoni (Groves 2001).
Presbytis siamensis rhionis
Known for certain only from Pulau Bintang, in the Riau Archipelago, Indonesia; might occur on Pulau Batam and Pulau Galang as well (Groves 2001).
Presbytis siamensis cana
Occurs in Indonesia. Found in eastern Sumatra between the Siak and Inderagiri Rivers, and on Palau Kundur in the Riau Archipelago (Groves 2001).
Presbytis siamensis paenulata
Occurs in Indonesia. Found in east-central Sumatra, where it is confined to a small wedge of coastal forest and with a population isolate reported from near Lake Toba (Groves 2001).