In September 2016, the International Union for Conservation of Nature (IUCN) listed 507 endangered mollusc species. Of all evaluated mollusc species, 7.0% are listed as endangered. The IUCN also lists nine mollusc subspecies as endangered. No subpopulations of molluscs have been evaluated by the IUCN. For a species to be considered endangered by the IUCN it must meet certain quantitative criteria which are designed to classify taxa facing "a very high risk of extinction". An even higher risk is faced by critically endangered species, which meet the quantitative criteria for endangered species. Critically endangered molluscs are listed separately. There are 1088 mollusc species which are endangered or critically endangered. 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 endangered mollusc species and subspecies evaluated by the IUCN.
Gastropods There are 448 species and seven subspecies of gastropod assessed as endangered.
Stylommatophora Stylommatophora is a very diverse group that includes the majority of land snails and slugs. There are 187 species and two subspecies in the order Stylommatophora assessed as endangered.
Partulids
Achatinellids
Cerastids
Endodontids
Charopids
Helicarionids
Orthalicids Species
Subspecies
Orthalicus reses reses (Stock Island tree snail)
Euconulids
Streptaxids Species
Subspecies
Tayloria urguessensis subangulata
Camaenids
Helicids
Hygromiids
Other stylommatophoran species
Littorinimorpha There are 147 littorinimorph species and three subspecies assessed as endangered.
Hydrobiids
Bithyniids Species
Subspecies
Assimineids
Pomatiopsids
Other Littorinimorpha species
Sorbeoconcha
Architaenioglossa Species
Subspecies
Bellamya unicolor abyssinicus Maizania hildebrandti thikensis
Cycloneritimorpha
Hygrophila species There are 22 Hygrophila species assessed as endangered.
Planorbids
Lymnaeids
Neogastropoda
Other gastropod species
Bivalvia There are 57 species and two subspecies in the class Bivalvia assessed as endangered.
Unionida There are 54 species and two subspecies in the order Unionoida assessed as endangered.
Margaritiferids
Unionids Species
Subspecies
Catspaw (Epioblasma obliquata obliquata) Rough rabbitsfoot (Quadrula cylindrica strigillata)
Other Unionida species
Venerida
Cephalopods Cirroctopus hochbergi Opisthoteuthis mero
See also Lists of IUCN Red List endangered species List of least concern molluscs List of near threatened molluscs List of vulnerable molluscs List of critically endangered molluscs List of recently extinct molluscs List of data deficient molluscs
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