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.
Range & Status
Previously recorded in Cornwall, Devon, Somerset, Gwent, Hereford and Worcester; now scattered records from Devon, Gwent and the River Wye.
The single record for Cornwall is mentioned in the Victoria County History (Clark, 1906).
Habitat & Ecology
Occurs in rivers amongst vegetation (including tree roots) in slow-flowing regions.
It is a pollution sensitive species.
The host watercourses should be given special recognition to ensure protection against changes to river morphology, water quality and bankside management.
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.