This work aims to determinate the spatial distribution of two sympatric freshwater shrimp species, Potimirim glabra (Kingsley, 1878) and Potimirim potimirim (Müller, 1881) in Sahy River, municipality of Mangaratiba. The populations were collected from September, 1997 to February, 1999. The animals were collected monthly by sieving the marginal vegetation, on rocky surface and among litter on river bottom. The animals were sorted sexed. Their carapace length measured and total length measured. A total of 4,889 animals were collected in Sahy River: 3,281 P. glabra and 1,608 P. potimirim. The spatial distribution of P. glabra and P. potimirim showed an environmental partition. Potimirim glabra occurred in abundance at the farthest stations from the beach, wilst and P. potimirim, at the nearest stations from the sea.
Potimirim glabra; Potimirim potimirim; spatial distribution; environmental partition