Cold, Warm, Temperate and Brackish: Bivalve Biodiversity in a Complex Oceanographic Scenario (Uruguay, Southwestern Atlantic)*

Abstract

Abstract: The temperate zone of the southwestern Atlantic Ocean (23–42°S), which includes the Patagonian Shelf Large Marine Ecosystem and the Subtropical Convergence Zone, is one of the most productive areas of the Southern Hemisphere. Key features of this region are a wide continental shelf, the convergence of cold and warm currents, and continental freshwater input of the La Plata River. The Uruguayan marine and estuarine waters are at the core of this zone. The marine and estuarine bivalve fauna of Uruguay has received good attention since the publication of the Voyage of Alcide d'Orbigny (1834–1846). Here we provide an overview of taxonomic, faunistic and biogeographic issues, identifying knowledge gaps and highlighting priorities for future research. The main threats for that fauna are discussed, with emphasis on species of current or potential socioeconomic interest. Of the 231 species reported from the area, only four species are strictly estuarine: Erodona mactroides Bosc, 1801, Tagelus plebeius (...