Posterodistal angle of epimeral plate 3 slightly produced, posterior margin sinuous. Head with the lateral lobes only weakly produced, truncated; eyes moderately large, rounded, black in colour. Antenna 1 reaching little beyond peduncle of antenna 2, flagellum up to about 11-articulate in male, up to 7-articulate in female. Antenna 2 quite short and robust, less than three times length of head, flagellum up to about 12-articulate in male, about 9-articulate in female; flagellar articles with numerous very short setae. Gnathopod 1 basis in male short and robust, tapering proximally, carpus with rounded posterior lobe and small group of marginal spines, propodus rectangular, palm convex and almost transverse, delimited by small spine, posterior margin with small group of spines. Gnathopod 1 in female generally similar to male except basis slender and propodus more narrowly rectangular. Gnathopod 2 basis in male with broad anterior lobe, posterior margin with only few short spinules, propodus very large and robust, oval, palmar margin less than half length of posterior margin, palm convex and weakly oblique delimited by obtuse process, dactylus robust. Gnathopod 2 in female slightly larger than 1 but generally similar, basis with more pronounced anterior lobe. Pereiopods 3 and 4 only sparsely setose, propodus usually without a group of setae on the anterior mid-margin. Pereiopods 5 to 7 robust, spinose, in female numerous setae may be present amongst spines, basis broadly rounded, posterior margin weakly crenulate, propodus without group of setae on posterior mid-margin. Uropods short and spinose; uropod 3 rami shorter than peduncle.
Up to 8 mm.
Variable brown to green.
Intertidal on rocky shores amongst algae and extending into the shallow subtidal.
Arctic Ocean; North Atlantic, American and European coasts; North Sea. European coasts from northern Norway and Iceland to Atlantic coast of France.