GB rarity status: Nationally Scarce
This coastal pill-woodlouse (to 6mm in length) is poorly pigmented, typically a mottled ‘sand’ colour, and the body surface is covered in minute spines. It has a characteristic stance when disturbed where the body partly enrols to leave a few pairs of protruding legs to grip the underlying substrate. It can be confused with juveniles of Armadillidium vulgare.
Distribution and Habitat
It is uncommon, and occurs sporadically around the British coastline as far north as the Scottish borders, and is known at several sites on the east coast of Ireland. It is strongly associated with undisturbed sand-dune systems, favouring a particular sand grain size, more rarely in salt marsh.
It is typically associated with storm strandline debris, where it is found clinging to the underside of driftwood, hiding within crevices, or at depths of 20-30 cm into underlying sand. It may occur with Armadillidium vulgare.
This summary is based on the detailed account in Gregory (2009).