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 rare species, found living in only five sites on the south British coast as far as west
Sussex. Until recently known only from shells in Cornwall (shell sand at Porthcurno in the 19th century and in 1976; shell sand Falmouth area in the 19th century; and a single shell at Fowey in 1962). The first confirmed living record was in 1998 in St. Mawes Bay. It feeds on vegetable detritus and small algae (Fretter & Graham, 1978) and lives at the base of moist rotting Eelgrass Zostera spp. or saltmarsh vegetation at high water in sheltered tidal lagoons and estuaries where there is full salinity (Graham, 1988).
Destruction or pollution of seagrass and saltmarsh vegetation. Graham (1988) suggests that it has already suffered from destruction of many sites.
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.