The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Habitat & distribution
A warm-water species of hermit crab at the northern limit of its distribution range. It has a very exacting habitat, being found on shores with extensive reefs and where the slate rocks have steeply-tilted bedding planes. Here it usually occurs in very shallow pools or damp crevices, between MHWN and MTL, and moderately exposed to wave action. It seems to have a preference for the shells of Dogwhelk Nucella lapillus . First described as new to the British fauna in 1959, its numbers have declined since 1967. An uncommon species recorded in the Channel Islands; formerly sporadic in south Devon and Cornwall.
The spillage of oil from the Torrey Canyon in 1967 and the subsequent use of industrial detergents eliminated this species from many of its known sites. The last known record was from Battery Rocks, Penzance in 1985. Elsewhere it extended its range southwards to Brittany through to the Azores and the Mediterranean.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.