page_title: List of non-marine molluscs of Great Britain
hierarchical_section_title: List of non-marine molluscs of Great Britain
caption_attribution_description: English: Illustrated Index of British Shells. Plate XXIII. Fig.Name in textAccepted name (2013)1Helix pisana MüllerTheba pisana2Helix aspersa MüllerHelix aspersa3Helix virgata CostaCernuella virgata4Helix cantiana MontaguMonacha cantiana5Helix ericetorum MüllerHelicella itala6Helix rufescens PennantArianta arbustorum7Helix lapicida LinnaeusHelicigona lapicida8, 9Helix hispida LinnaeusTrochulus hispidus10Helix fusca MontaguZenobiella subrufescens11Helix sericea DraparnaudTrochulus sericeus12Helix obvoluta MüllerHelicodonta obvoluta13Helix fulva MüllerEuconulus fulvus14Helix pomatia LinnaeusHelix pomatia15Helix caperata MontaguCandidula intersecta16Helix carthusiana MüllerMonacha cartusiana17, 18Helix nemoralis LinnaeusCepaea nemoralis19Helix arbustorum LinnaeusArianta arbustorum20, 21Helix rotundataDiscus rotundatus22, 23Helix pulchella MüllerVallonia pulchella24Helix revelata FérussacPonentina revelata25Helix apertaHelix aperta26Helix umbilicata MontaguPyramidula umbilicata27Helix pygmæa DraparnaudPunctum pygmaeum28Helix lamellata JeffreysSpermodea lamellata29Helix aculeata MüllerAcanthinula aculeata
context_page_description: This list comprises 231 species of non-marine molluscs that have been recorded in the scientific literature as part of the fauna of the island of Great Britain; this total excludes species found only in hothouses and aquaria. The list includes terrestrial and aquatic gastropods, and aquatic bivalves. Molluscs that are fully marine are not included here, except for two marine pulmonate snails. In other words, this list includes land snails and slugs, and freshwater and brackish water snails. It also includes freshwater mussels and clams, including some that can tolerate brackish water.
  Great Britain is a European island in the northeastern Atlantic, comprising the contiguous countries of England, Scotland and Wales. The mollusc fauna of the island of Ireland, which includes both the Republic of Ireland and Northern Ireland, is listed in another article: List of non-marine molluscs of Ireland.
  A number of species of snails listed here are sometimes also found on lists of marine species. Two listed here, in the genera Onchidella and Otina, are fully marine in habitat, but are pulmonate snails that breathe air at low tide rather than having gills like most marine species.
context_section_description: This list comprises 231 species of non-marine molluscs that have been recorded in the scientific literature as part of the fauna of the island of Great Britain; this total excludes species found only in hothouses and aquaria. The list includes terrestrial and aquatic gastropods, and aquatic bivalves. Molluscs that are fully marine (adapted to live in the sea) are not included here, except for two marine pulmonate snails. In other words, this list includes land snails and slugs, and freshwater and brackish water snails. It also includes freshwater mussels and clams, including some that can tolerate brackish water.
  Great Britain is a European island in the northeastern Atlantic, comprising the contiguous countries of England, Scotland and Wales. (Great Britain is not the same entity as the United Kingdom of Great Britain and Northern Ireland; for more information on the complex nomenclature of this area, please see terminology of the British Isles.) The mollusc fauna of the island of Ireland, which includes both the Republic of Ireland and Northern Ireland, is listed in another article: List of non-marine molluscs of Ireland.
  A number of species of snails listed here are sometimes also found on lists of marine species. Two listed here, in the genera Onchidella and Otina, are fully marine in habitat, but are pulmonate snails that breathe air at low tide rather than having gills like most marine species. Other species listed here live in habitats that are intermediate between land and saltwater, or in brackish water habitats intermediate between freshwater and full-salinity saltwater.
  Additional species are still being added to the list of the non-marine malacofauna of Great Britain. Four of the more recent discoveries are: Papillifera papillaris, first recorded in 1993 but probably the result of introductions with Italian statuary a century or more earlier; Selenochlamys ysbryda, a species new to science, which was first found in 2004; Candidula olisippensis, discovered on a Cornish cliff in 2011; and Monacha ocellata, found near Tilbury docks in 2017. Other species have been added to the list as a result of taxonomic revisions; for instance, only in 2009 was it recognised that snails previously known as Pupilla muscorum constituted two sibling species occupying different habitats, with both Pupilla muscorum sensu stricto and Pupilla pratensis occurring in Britain. A major revision of the slug fauna published in 2014, partly based on genetic sequencing, established that there were 20% more species than had previously been recognised. Not all these species have been definitely identified and some are formally undescribed.
  In addition to the species that survive outdoors in Great Britain, there are also another 14 exotic gastropod species (some terrestrial and some aquatic) which live as "uninvited guests" in greenhouses and their enclosed aquaria. These species are known as "hothouse aliens", and are listed separately at the end of the main list. In this list these species are not counted as part of the fauna. Also not included are species such as Eobania vermiculata and Milax nigricans that have been found outdoors on single occasions but seem never to have established persisting populations.
  The following table shows a summary of species numbers.
caption: A plate from G. B. Sowerby's 1859 book Illustrated Index of British Shells shows some shells of British land snails
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