The region of Porto Rico, on the Upper Paraná River, is a contact zone between the Atlantic Rainforest and the Cerrado, with elements of the Pantanal wetlands. During surveys from September 2003 to September to 2005, we recorded the presence of non-volant mammals on 14 islands and the adjacent riverbanks. Surveys were by foot and by boat, and we also interviewed local people about the mammals of the region. Sightings of three primate species - Cebus nigritus (Goldfuss, 1809) (left margin of the river), C. libidinosus Spix, 1823 (right margin) and Alouatta caraya (Humboldt, 1812) (both margins and 12 islands) - were plotted on a satellite image. Alouatta clamitans Cabrera, 1940 was not recorded. However, interviews indicated that this species has occurred in this region in the past. The survey of mammals revealed the occurrence of 32 native species, a native genus with one or more unidentified species, and two introduced species [Lepus europaeus Pallas, 1778 and Sus scrofa (Linnaeus, 1758)]. The study discusses the permeability of the Paraná River to dispersal, as well as its potential as a geographical barrier to some species. Hypothesis on the local extinction of A. clamitans is also addressed. This study provides information that can be useful for promoting the conservation of this region.
Exotic species; gallery forest; geographical barrier; neotropical primates
