Invasive freshwater gastropods in South America: Physa acuta and its expansion to Austral Patagonia in Argentina

Physa acuta is a freshwater snail of North American origin that has spread to all continents. In South America it was detected for the first time in 1966 (Brazil) and is currently present in Argentina, Brazil, Peru, Chile, Colombia, Ecuador and Uruguay, occupying 13 of the 52 South American freshwater eco-regions. Its introduction would be related to the import and transportation of aquatic plants. Here we update the distribution of P. acuta in Argentina based on a review of scientific collections, published works and new collections. Our review expands the distribution of the species from 11/23 Argentine provinces (until 2010) to 19/23, and we report the first record for the province of Santa Cruz, this being the southernmost site of the species. This new discovery in the province of Santa Cruz (Austral Patagonia), with an established and reproducing population in an urban area, poses a potential threat to local biodiversity (where there are no records of other non-native mollusks) and to human and animal health. This is due to the finding of populations in southern Argentina that are naturally infested by Fasciola hepatica. The record of P. acuta in aquatic environments of southern Patagonia makes it necessary to generate monitoring and control plans with the objective of identifying the dispersion vectors and preventing the spread of the species in other water bodies in the region.