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Defolin’s lagoon snail
Caecum armoricum
This tiny creature, measuring only 2mm long, looks nothing like the more familiar sea snails. Defolin’s lagoon snail has neither a spiral shell (typical of, for example, whelks) or a domed limpet-like shell, but is instead shaped like a slightly curved test-tube.
A very rare creature, Defolin’s lagoon snail lives between small pebbles high on the beach, where seawater seeps through the shingle to form lagoons.
As it is so rare, Defolin’s lagoon snail is very vulnerable. Any changes to the lagoons in which it lives could result in the complete disappearance of the lagoon snails.
Coastal lagoons are often transient, and may disappear through natural beach movement. Human actions, such as the construction of coastal defences, can cause beaches to shrink or grow, and so can speed up the loss of coastal lagoons.
Brief description of European distribution
In this country, live colonies have been found only in Fleet, Lydd Ranges and Pagham Harbour SSSI. Outside England there is one site on the coast of north Africa in the South Gibraltar Strait. Shell records have been found in Ireland, the Atlantic coast from Gibraltar to the Channel, the Black Sea, and Mediterranean.
Conservation status / need
Nationally rare marine animal
Protected under Schedule 5 of the Wildlife and Countryside Act 1981
The coastal lagoons in which Defolin’s lagoon snails are found are a UKBAP priority habitat and are listed in Annex I of the Habitats Directive
Further information sources
DeFolin's lagoon snail - Caecum armoricum
(MarLIN)
Saline lagoons (UKBAP)
