List of non marine molluscs of Great Britain

This list comprises 220 species of non-marine molluscs that have been recorded in the scientific literature as part of the fauna of the island of Great Britain. These are terrestrial and aquatic gastropods, and aquatic bivalves; the list does not include species of molluscs which are considered to be fully marine, except for two marine pulmonate gastropods.

Contents

• Conservation
• Systematic list
• Gastropoda
• Bivalvia
• List of hothouse alien species
• References

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. Molluscs that are fully adapted to live in the sea are not included here, except for two species that are air-breathing and thus are more closely related to most land and freshwater snails than they are to the majority of sea snails.

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 semi-terrestrial and so 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 which 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. Three of the more recent discoveries are Papillifera bidens first found in 1993, Selenochlamys ysbryda a species which appeared to be new to science and which was first found in 2005, and Eobania vermiculata first found in 2006 and possibly not really established at that point. 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.

The following table shows a summary of species numbers.