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.