List of vulnerable molluscs
As of September 2016, the International Union for Conservation of Nature (IUCN) lists 879 vulnerable mollusc species. 12% of all evaluated mollusc species are listed as vulnerable. The IUCN also lists 18 mollusc subspecies as vulnerable. No subpopulations of molluscs have been evaluated by the IUCN. For a species to be assessed as vulnerable to extinction the best available evidence must meet quantitative criteria set by the IUCN designed to reflect "a high risk of extinction in the wild". "Endangered" and "critically endangered" species also meet the quantitative criteria of "vulnerable" species, and are listed separately . See: List of endangered molluscs, List of critically endangered molluscs. Vulnerable, endangered and critically endangered species are collectively referred to as "threatened species" by the IUCN. Additionally 1988 mollusc species (27% of those evaluated) are listed as "data deficient", meaning there is insufficient information for a full assessment of conservation status. As these species typically have small distributions and/or populations, they are intrinsically likely to be threatened, according to the IUCN. While the category of "data deficient" indicates that no assessment of extinction risk has been made for the taxa, the IUCN notes that it may be appropriate to give  them "the same degree of attention as threatened taxa, at least until their status can be assessed." This is a complete list of vulnerable mollusc species and subspecies evaluated by the IUCN. Gastropods. There are 828 species and 16 subspecies of gastropod assessed as vulnerable. Stylommatophora. Stylommatophora includes the majority of land snails and slugs. There are 339 species and six subspecies in the order Stylommatophora assessed as vulnerable. Vertiginids. Species Subspecies Helicids. Species Subspecies Hygromiids. Species Subspecies Other Stylommatophora. Species Subspecies Littorinimorpha. There are 324 species and seven subspecies in the order Littorinimorpha assessed as vulnerable. Hydrobiids. Species Subspecies  Sorbeoconcha. There are 55 species in the order Sorbeoconcha assessed as vulnerable. Architaenioglossa. Species Subspecies Hygrophila. Species Subspecies Bivalvia. There are 49 species and two subspecies in the class Bivalvia assessed as vulnerable. Unionida. There are 37 species and two subspecies in the order Unionoida assessed as vulnerable. Unionids. Species Subspecies Iridinids. Species Subspecies