Jaera hopeana Costa, 1853
Jaera are small, ubiquitous intertidal marine isopods which can be identified to species by the examination of male reproductive structures (specifically the preoperculum) and pereopods. Preopercula can be examined using a binocular dissecting microscope, but examination of pereopods is best done using a compound microscope at low power.
Jaera hopeana is a small ectocommensal species (males 1.5mm, females up to 2.0mm). The male preoperculum is diagnostic, having narrow, long arms. See further the Identifying Jaera page.
Recorded only from a single location (and not recently) in south Devon, living ectocommensally on the ventral surface of the marine isopod Sphaeroma serratum near a freshwater seepage between HWN and MTL.
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.