The Amazon marmosets are poorly known and severely threatened – endemic to the arc of deforestation in southern Amazonia. Based on data from field expeditions across this global deforestation frontier, we provide new records and extend the range of Mico chrysoleucos, provide new records and refine the range of M. acariensis, report the first records of a species of Mico on permanently flooded forests, and hypothesize the existence of a hybrid zone of these two species and also M. melanurus.

This paper discusses the status of a tamarin specimen housed at the American Museum of Natural History that is wrongly labelled as Saguinus fuscicollis tripartitus and might represent a species or subspecies unknown so far or a hybrid.

Baboons occur in a large range of different habitats. However, data on the ecology of Guinea baboons were scarce. We provide information on the ranging behaviour, habitat use, and diet of a population of Guinea baboons in the Niokolo-Koba National Park, Senegal. Home ranges were about 25 km², and they moved up to 13 km per day. They seem to prefer the more forested parts of their home range near the river. Fruit dominates their diet, and the nuts of the palmyra palm are a year-round food source.