The Sabinas River basin in Coahuila, a new hotspot of molluscan biodiversity near Cuatro Cienegas, Chihuahuan Desert, northern Mexico

The malacofauna of the Sabinas River basin, Coahuila, North Mexico, was studied at 9 sites. In total, 21 native and 2 invasive species were found. Nineteen species were gastropods and 4 species were bivalves. One genus and 2 species of subterranean gastropods are endemic to the area. We report for the first time, a member of the family Amnicolidae in Mexico, Lyogyrus sp. Mexithauma cf. quadripaludium Taylor, 1966 and Juturnia coahuilae (Taylor, 1966) (Cochliopidae), previously known only as endemic in the neighboring Cuatro Cienegas basin, were found for the first time outside of this basin. Also, Cincinnatia integra (Say, 1821) (Hydrobiidae), previously known in Mexico only from 1 relict site in San Luis Potosi state, was found living in Sabinas River. In all studied sites, the invasive species Melanoides tuberculata (O. F. Muller, 1774) (Thiaridae) and Corbicula fluminea (O. F. Muller, 1774) (Cyrenidae) dominate the aquatic molluscan communities. Both molluscs are potential risks for native species, especially if the water pollution continues. At least 10 species from Sabinas River System are of special conservation significance (7 imperiled and 3 vulnerable), due to their endemism, extremely reduced habitat, or relict occurrence in Mexico.