The taxonomy proposed in 2003 was followed in Mammal Species of the World in 2005. In the study in 2003, a direct comparison of C. israelita and the type specimen of C. chiropotes was not included, but it is assumed that bearded sakis in Venezuela are C. israelita, while C. 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 C. chiropotes is from Venezuela, which could leave israelita as a junior synonym of C. chiropotes, thereby matching the taxonomy proposed in 2002. Due to this confusion, neither C. sagulatus nor C. israelita were recognized by the IUCN in 2008, which maintained all bearded sakis north of the Amazon River as C. chiropotes. However, regardless of the uncertainties over exactly what population the species 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. References Further reading Peters, G.; T. Haus; and R. Hutterer (2014). Neotropical primates from the Cologne Zoo in the collections of the Zoologisches Forschungsmuseum Alexander Koenig: noteworthy specimens, taxonomic notes and general considerations. Bonn zoological Bulletin 63 (2): 173–187. red-backed bearded saki Mammals of Brazil Mammals of Venezuela Mammals of Suriname Mammals of Guyana Mammals of French Guiana red-backed bearded saki Taxa named by Alexander von Humboldt