Distribution. Widespread in the upper Amazon, extending from NW Brazil (W of rios Negro, upper Uaupés, and Amazonas-Solimoes) into SE Colombia (S of the Rio Tomo in the Orinoco Basin, and perhaps the upper Rio Guyabero), and S into the Ecuadorian Amazon and NE Peru (to the N bank of the rios Maranon and Amazonas, W as far as the Rio Chinchipe); it occurs also S of the Rio Solimoes in a small area on the lower Rio Purus. Ma's Night Monkey (A. nancymaae) replaces it in a small enclave N of the Rio Maranon between the lower rios Tigre and Pastaza. in Aotidae - Russell A. Mittermeier (Lynx Edicions, 2013)