|Brown-backed Bearded Saki|
|Range||Amazon in north-western Brazil (north of the Rio Negro and west of the Branco River) and southern Venezuela.|
The Brown-backed bearded saki (Chiropotes israelita) is a species of bearded saki, a type of New World monkey. It is endemic to the Amazon in north-western Brazil (north of the Rio Negro and west of the Branco River) and southern Venezuela. It is possible the correct scientific name for this species is Chiropotes chiropotes, in which case the more easternly Red-backed bearded saki would be named Chiropotes sagulatus.
Previously, this and all other dark-nosed bearded sakis were included as subspecies (or taxonomically insignificant variations) of Chiropotes satanas. Based on molecular and morphological evidence, Chiropotes utahickae, Chiropotes chiropotes and Chiropotes sagulatus were split from Chiropotes satanas in 2002. Chiropotes chiropotes and C. sagulatus were the only members of the genus found north of the Amazon River, with the former west of the Branco River (a major zoogeographic barrier) and the latter east. Supporting evidence for the basic split into four species of dark-nosed bearded sakis was published in 2003, though with one significant difference compared to the earlier study: They treated the population east of the Branco River as Chiropotes chiropotes (Chiropotes sagulatus in the 2002 study) and west of the river as Chiropotes israelita (Chiropotes chiropotes in the 2002 study). The taxonomy proposed in 2003 was followed in Mammal Species of the World in 2005. In the study in 2003, a direct comparison of Chiropotes israelita and the type specimen of Chiropotes chiropotes was not included, but it is assumed that bearded sakis in Venezuela are Chiropotes israelita, while Chiropotes chiropotes is not present in that country, thereby matching what would be expected from a species pair separated by the Branco River. This is potentially problematic, as the type specimen of Chiropotes chiropotes is from Venezuela, which could leave israelita as a junior synonym of Chiropotes chiropotes, thereby matching the taxonomy proposed in 2002. Due to this confusion, neither Chiropotes sagulatus nor Chiropotes israelita were recognized by the IUCN in 2008, which maintained all bearded sakis north of the Amazon River as Chiropotes chiropotes. However, regardless of the uncertainties over exactly what population the specific name chiropotes belongs to, it is clear that there are two distinct populations of bearded sakis north of the Amazon River: A reddish-backed from the Branco River and eastward, and a brown-backed from the Branco River and westward.