Muriquis are endemic primates of the Brazilian Atlantic Forest, with two recognized species: Brachyteles hypoxanthus and Brachyteles arachnoides. Although the state of Rio de Janeiro is the type locality for B. arachnoides the muriqui population of this region was, until recently, poorly known. We report our surveys for muriquis in seven localities in the state. Our objectives were to estimate the number of muriquis remaining and to identify local threats. We recorded muriquis in Parque Nacional da Serra dos Órgãos, Parque Nacional do Itatiaia and Guapiaçu Private Reserve. Based on our sightings and information from local people we estimate that the remaining muriquis in Rio de Janeiro total c. 160, with 110 B. arachnoides and 50 B. hypoxanthus. The most severe threat to muriquis in these areas is hunting, followed by small population sizes, habitat fragmentation, forest disturbance and ecotourism. Central Rio de Janeiro state still harbours large tracts of intact forests potentially available to muriquis. Thus, if conservation actions could be targeted to mitigate the main threat of hunting there is potential for the recovery of muriquis in the state of Rio de Janeiro, at least in the short-term.
