Brown-backed bearded saki

The brown-backed bearded saki (Chiropotes israelita) is a New World monkey of the Amazon, one of the bearded sakis of the genus Chiropotes. It is endemic to north-western Brazil, north of the Rio Negro and west of the Branco River, and to southern Venezuela. Its standing as a species is unsettled. A 2003 study treated the bearded sakis west of the Branco River as C. israelita and those east of it as C. chiropotes, while a 2002 study used the names the other way round, and because the type specimen of C. chiropotes came from Venezuela, israelita could be a junior synonym. The IUCN lists the reddish-brown bearded saki as a valid species with israelita as a synonym, while noting that both might be valid. Whatever the names, two distinct populations live north of the Amazon River, a reddish-backed one east of the Branco River and a brown-backed one west of it.