Urosome segment 1 with a dorsal keel, segments 2 and 3 with a pair of dorsal spines. Coxal plates moderately large, plates 1 and 2 posterodistal angle with a small tooth. Epimeral plate 3 posterodistal angle with a small tooth, margin smooth. Head with lateral lobes truncated; eyes small, rounded. Antenna 1 almost half body length, peduncle article 1 robust, flagellum much longer than peduncle, multi-articulate; accessory flagellum about 4 or 5-articulate. Antenna 2 much shorter than 1, peduncle article 5 shorter than 4, flagellum equal to length of peduncle. Gnathopod 1 propodus shorter than carpus, both strongly setose, palm transverse, delimited by closely set group of curved spines. Female gnathopod 2 little larger than 1, elongate, propodus little longer than carpus, both strongly setose, palm oblique delimited by large spine, palmar margin spinulose. Male gnathopod 2 extremely large and very robust, merus and carpus very short, propodus enormous, suboval, palm not delimited from posterior margin, palmar margin very densely fringed with long setae, and with several small spines and rounded lobe close to base of dactylus, inner margin of carpus also with dense fringe of long setae, dactylus very elongate, in large specimens reaching almost entire length of propodus. Pereiopods 5 to 7 robust; pereiopod 7 basis with mid-posterior margin rather angular. Uropods 1 and 2 spinose; uropod 3 outer ramus equal to length of peduncle, inner ramus only half length of outer ramus. Telson short, cleft almost to base, each lobe rounded with apical spinule.
Up to 10 mm.
Depth range from the intertidal to about 100 metres; locally common amongst rich algal cover.
Mediterranean; Atlantic coast of Europe and North Africa to Shetlands.