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Volkmer-Ribeiro, C, Ezcurra De Drago and Parolin, M., 2007. Spicules of the freshwater sponge Ephydatia facunda indicate lagoonal paleoenvironment at the Pampas of Buenos Aires Province, Argentina. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 449 – 452. Gold Coast, Australia, ISSN 0749.0208 Sediments dredged at the site Puente de la Tropa by the banks along the middle reach of River Luján (34°34´40"S-59°08´14"W), northeastern Pampas of Buenos Aires Province, Argentina, were 14C dated as 4,000 (80 cm) and 11,000 (222cm) yr B.P. Abundant gemmular spicules of the freshwater sponge Ephydatia facunda (Weltner, 1895), were seen in the samples dated 11,060 and 10,420 yr B.P. The spicules were associated with diatoms together with a rich gastropod and ostracod fauna, silicophytoliths and fish bones. Hyalodiscus subtilis (Bailey) a brackish, benthic diatom dominated the diatom flora. The detected taxocene indicates the existence of a lagoonal environment in this area during the Pleistocene. The remarkable presence of E. facunda lends weight to this interpretation as the species has been proven to presently thrive in coastal lagoonal brackish to fresh water rivers and swampy areas along the Brazilian and Argentinean ocean border. A strong relationship was seen between the species and the enrichment by floating meadows that occurs in such areas, the corresponding organic enrichment of the waters and sediments and the reduction of the free water column. [ABSTRACT FROM AUTHOR]