Freshwater gastropods from del Plata basin, Argentina

Abstract

The greatest floral and faunal biodiversity estimated from Argentina -not including molluscs - is found in three subtropical forests belonging to the del Plata Basin, two of them at the northeastern part of Argentina (NEA). The aim of this study is to show new records as well as an update of the distribution of the freshwater Gastropoda species in the main NEA rivers: Iguazú, Paraná, Paraguay, and Uruguay. At NEA, 66 species belonging to 9 families are known from literature records. According to the preferences of habitats in this area littoral and bottom species, could be recognized. The former includes 33 species belonging to Ampullariidae, Ancylidae, Lymnaeidae, Physidae, and Planorbidae, and the latter with 33 species of Lithoglyphidae, Cochliopidae, Thiaridae, and Chilinidae. In this paper, 30 species of 8 families were recorded, 25 of them are littoral whereas only 5 species inhabiting the bottom were found, because of the high level of the rivers. Two new records were registered for the country, both belonging to Ancylidae: Gundlachia ticaga and the genus Laevapex. Thus, now there are 68 species at NEA. Twenty-three species increase the number of localities. Planorbidae was the family with more collected species (13). No Thiaridae species were found.