The freshwater snails (Mollusca: Gastropoda) of Mexico: updated checklist, endemicity hotspots, threats and conservation status

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 NatureServe Ranking, 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 21 genera, 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.