We present an updated checklist of native Mexican freshwater gastropods with data on their general distribution, hotspots of endemicity, threats, and for the first time, their estimated conservation status. The list contains 193 species,representing 13 families and 61 genera. Of these, 103 species (53.4%) and 12 genera are endemic to Mexico, and 75 species are considered local endemics because of their restricted distribution to very small areas. Using NatureServeRanking, 9 species (4.7%) are considered possibly or presumably extinct, 40 (20.7%) are critically imperiled, 30 (15.5%) are imperiled, 15 (7.8%) are vulnerable and only 64 (33.2%) are currently stable. With 61 species in 21genera, the Cochliopidae are the most diverse family, followed by the Planorbidae (37 species) and Pachychilidae (31). Pachychilus is the most species-rich genus with 30 species. Despite the high number of imperiled species (84), only 7 species (3.6%) are currently listed as endangered by the Mexican Secretariat of Environment and Natural Resources. We identified 3 hotspots and 2 potential centers of gastropod endemicity. Our research serves as a first step for determining priority areas for conservation of imperiled Mexican freshwater gastropods.

This paper describes a new genus, two new species and new records of subterranean gastropods from the Sabinas and Álamos River, Coahuila, and the Nazas River, Durango, in northern Mexico.Phreatomascogosgregoigen. n. et sp. n.from Don Martín Basin, Coahuila, is described based on shells and opercula that show some morphological similarities with shells ofPhreatodrobiaHershler & Longley, 1986 (Lithoglyphidae), which is a subterranean genus from neighboring area in Texas, United States. Conchologically, the new genus can be distinguished fromPhreatodrobiaand all other subterranean genera by a unique combination of characteristic shell morphology and opercula apomorphies.Balconorbissabinasensesp. n.(Cochliopidae) is the second species of this genus, which was previously known only from caves and associated subterranean habitats in Texas. The new record ofCoahuilixparrasense, Czaja, Estrada-Rodríguez, Romero-Méndez, Ávila-Rodríguez, Meza-Sánchez & Covich, 2017 (Cochliopidae) from Durango and Coahuila is the first record of extant member of this genus out of its hitherto known habitat in the Cuatro Ciénegas basin, Coahuila. These records are remarkable becauseC.parrasensehad been described recently as a fossil species. Shell morphologies of the new subterranean snails could be interpreted as possible evolutional adaptations to different hydrodynamic and other specific conditions in their habitat.