Nuevos registros de la almeja asiática invasora Corbicula fluminea (Bivalvia: Veneroida: Cyrenidae) en humedales de las cuencas Papaloapan, Grijalva y Usumacinta

First records of the Asian clam Corbicula fluminea (O. F. Müller, 1774) are provided for wetlands in the Papaloapan, Grijalva and Usumacinta basins. A total of 1,668 individuals were colected in 7 localities in Papaloapan, 16 in Grijalva and 24 in Usumacinta basins, sampling was performed from June 2011 to September 2015, in riverine, lacustrine and estuarine wetlands, in a variety of substrates from silt to sand and rocks, and substrates with vegetation. The highest abundances were in lacustrine wetlands and in the Usumacinta watershed. This study contributes with records in 47 localities and also, to the knowledge of exotic species in southern Mexico even when the ecological and economic impacts that this species may cause have not been assessed so far.