The serrated edges of the uropod exopod and the plumose setae on pereopods 1-3 distinguish this pill isopod from other Sphaeromatid species. The propodus of the first pereopod has 15-20 distal setae. Males up to 11.5mm, females up to 10.0mm.
Distribution and Habitat
Found on south and west coasts of Britain and Ireland and sporadically elsewhere, under stones and in crevices around MTL.
Jacobs, B. J. M. 1987. A taxonomic review of the European, Mediterranean and NW. African species generally placed in Sphaeroma Bosc, 1802 (Isopoda: Flabellifera: Sphaeromatidae). Zoologische Verhandelingen 238, 3-71.
Naylor, E. & A. Brandt. 2015. Intertidal Marine Isopods. Synopses of the British Fauna (New Series), No. 3. Field Studies Council, for The Linnean Society of London.