According to Hershkovitz (1977), Mico humeralifer is

expected to occur in the Sucundurí-Tapajós-Juruena inter-fluve. Rylands (1994) suggested that this species ’ range could extend as far south as 8º S. This study however, does not support these expectations. It is possible that Mico mauesi’s range extends between the Rios Sucundurí and Juruena, reaching as far south as the transition between dense tropical forest, open tropical forest and savanna (BRASIL, 1975) at around 7°40´S, or even as far as the Serra do Sucundurí at 8°10´S. These predictions coin-cide with the southern limit for M. humeralifer proposed by Rylands (1994). According to Rylands (1981), south of this latitude the species M. melanurus should occur between the Rios Aripuanã and Juruena. This hypothesis is partially supported by the occurrence of M. melanurus in the Serra do Sucundurí (08°34’S, 59°08’W) and on th