Distribution of the genus Anodontites (Mollusca: Bivalvia: Mycetopodidae) in Uruguay

Seven species of the freshwater mussel genus Anodontites were recorded from Uruguay. The populations of these bivalves suffer the negative effects of invasive bivalves, damming, industrial and urban discharges, and agrotoxic runoff. The distribution of these species is generally characterized at the level of basin or politic divisions, and precise geographic records are scarce. In order to detail the distribution of those species, the most representative collections of Uruguay were examined, the material of Anodontites was identified (612 records) and geographic coordenates were assigned at each locality (213 localities), using Geographic Information System (GIS) to obtain a distribution map for each species. Most of the localities with Anodontites were located in the left margin of Uruguay River and southwest of Uruguay, mainly in Soriano, Artigas, Salto and Colonia departments. The Salto Grande basin presented the highest species richness. The species with a highest number of records was A. patagonicus, which was also recorded in all basins. A. trapesialis and A. tenebricosus had a wide distribution and a high number of records. A. lucidus and A. ferrarisii, had a wide distribution (more than 6 basins) but comparatively lower number of records. Finally A. trapezeus and A. trigonus showed a limited distribution. There is a critical lack of samples in Merin Lagoon, Atlantic and Upper Negro River basins. It is necessary to carry out new sampling considering many variables in order to evaluate the current distribution and the ecologic preferences for each species.Original Abstract: Se han registrado siete especies de almejas dulceacuicolas del genero Anodontites en Uruguay. Las poblaciones de estos bivalvos estarian sufriendo efectos negativos por la presencia de bivalvos invasores, represamiento de rios, vertidos industriales y urbanos y escorrentia de agrotoxicos. La distribucion de estas especies esta generalmente caracterizada a nivel de cuenca o divisiones politicas siendo aisladas las citas de localidades puntuales. Para caracterizar detalladamente la distribucion de las mismas fueron revisadas las colecciones mas representativas de Uruguay, determinando el material (612 registros) y asignando coordenadas geograficas a cada localidad (213 localidades). A traves de un Sistema de Informacion Geografica (SIG) se confeccionaron mapas de distribucion de las especies. Las localidades presentes en las colecciones se situaron principalmente en el litoral del R