New records of freshwater mussels (Unionida, Unionidae and Mycetopodidae) from rivers, lakes, and lagoons in El Salvador, with notes on the expansion of invasive mollusc species

We examined 35 sites across 24 rivers, lakes, and lagoons in El Salvador and documented two native and one non-native freshwater mussel species in addition to the invasive Corbicula. Phylogenetic analyses supported the synonymy of Nephronaias lempensis Marshall, 1926, under Nephronaias goascoranensis (Lea, 1858). Mussel distributions were patchy; Mycetopoda subsinuata (Sowerby, 1868) occurred in soft, lentic habitats, whereas N. goascoranensis occupied a broader range. Sinanodonta pacifica (Heude, 1878), a non-native species, occurred in the upper Lempa basin, and Corbicula showed recent expansion. These results provide essential data for conservation planning.