Length: 9-13 mm. Head and body smooth except for antero-lateral projections on pereonites 2, 3 + 4. Head angular at front. Body and gnathopods 2 covered in minute sensory hairs. Antenna 1 approximately equal to cephalon plus pereonite 2, peduncle articles 2 and 3 setose; antenna 2 longer than antenna 1 peduncle, flagellum with short setae. Gnathopod 1 with serrate grasping margin to propodus and dactylus. Gnathopod 2 attached posterior to median of pereonite 2; basis with lateral and median anterior ridges; propodus very large, width less than half length; palmar surface with small proximal spine, prominent distal poison spine separated by cleft from more distal triangular projection. Dactylus heavy and slightly curved, inner margin slightly denticulate. Gills round. Pereopods 5 to 7 increase in length; propodus palm concave with proximal grasping spines. Female differs in having short pereonite 1; gnathopod 2 propodus palm has proximal grasping spine and accessory spine, distal minute poison spine; pereopods much more slender.
China; Vladivostok and Beringa Is. Russia; Akkeshi Bay, Japan; Alaska; Coos Bay (OR)
Caprellid, “Ghost” or “Skeleton” shrimps, so called for their skeletal appearance. Amphipod crustaceans, easily distinguished by the elongate stick-like body form and reduction of the abdominal appendages. Head is generally fused with pereonite 1. Pereopods on first 2 segments (pereonites) are most flexible and called gnathopods; gnathopods 2 being the largest, used in defense, feeding and substrate attachment. In many species pereopods 3 and 4 may also be reduced or absent. Gills on pereonites 3 + 4, rarely on pereonite 2. Pereopods 5 - 7 much smaller than 1 + 2, used for clinging to the substratum. In females, brood plates (öostegites) develop on pereonites 3 + 4. Much remains to be learnt about their biology, ecology and in many cases changing distributions.
Surface – 15m. In fouling communities
Probably introduced to Coos Bay (Oregon, N. America) in ship fouling from Japan; now known from as far south as San Francisco Bay (Ashton pers. obs.)
National Museum of Natural History, Washington DC: (NMNH) 13331; Chamisso Harbor; Esch-Scholts Bay; Alaska; WHDall 3677 (1701) 5-8 ftms; (NMNH) 13446; Bering Island; Commander Ids; Siberia; Leonhard Stiejneger; 1882-83 (no. 2383 4)
