Distribution. Brazilian Amazon, S of the Rio Amazonas, between the Tapajos/Juruena system and the Tocantins/Araguaia river system to the E, in the Brazilian states of Para and Mato Grosso; the exact S limit ofits distribution is unclear, but it seems likely that it coincides with the transition between the Amazon rainforest and the cerrado savannas of C Brazil; this ecotone encompasses headwaters of the Xingu and Tapajos river systems in N Mato Grosso. Vieira's Titi (C. vieirai) is also known to occur in this region, but there are too few records to confirm whether their distributions intergrade, or in fact where the exact limits of their distributions are. One recent study also found that the Red-bellied Titi may be absent from or present at extremely low densities in large areas of the Tocantins-Xingu interfluvium. Given the overall lack of records, while it is clear that the Red-bellied Titi occurs over a vast area of the SE Amazon Basin, the exact limits of its distribution within this area remain unclear. in Phitheciidae

Distribution. Brazilian Amazon, S of the Rio Amazonas, between the Tapajos/Juruena system and the Tocantins/Araguaia river system to the E, in the Brazilian states of Para and Mato Grosso; the exact S limit ofits distribution is unclear, but it seems likely that it coincides with the transition between the Amazon rainforest and the cerrado savannas of C Brazil; this ecotone encompasses headwaters of the Xingu and Tapajos river systems in N Mato Grosso. Vieira's Titi (C. vieirai) is also known to occur in this region, but there are too few records to confirm whether their distributions intergrade, or in fact where the exact limits of their distributions are. One recent study also found that the Red-bellied Titi may be absent from or present at extremely low densities in large areas of the Tocantins-Xingu interfluvium. Given the overall lack of records, while it is clear that the Red-bellied Titi occurs over a vast area of the SE Amazon Basin, the exact limits of its distribution within this area remain unclear.