Range extension for three species of South American freshwater crabs (Crustacea: Decapoda: Trichodactylidae)

New sampling programs have extended the distribution of three species of freshwater crabs (family Trichodactylidae): Dilocarcinus septemdentatus and Sylviocarcinus pictus from the Amazon basin to southern South America, and S. australis, from the north of Argentina southwards. The three species are now found in the floodplain of the middle Parana River (31 degrees 39'S, 60 degrees 45'W). The extension of their distribution is approximately 500 km and 2000 km further south. The number of freshwater crab species in the alluvial valley of the Parana River has increased by 30\% with these new records.