Urosome segments 2 and 3 with a single dorsolateral spine and few setae, segment 1 with numerous dorsal setae but no spines. Coxal plates 1 to 4 with the distal margin densely setose in male, very sparsely setose in female. Epimeral plate 3 obtusely quadrate, posterior margin with short setules, distal margin with 7 to 8 groups of long setae. Head with lateral lobes broadly truncated, upper angle slightly produced; eyes large, elongate or weakly kidney-shaped. Antenna 1 peduncle article 1 equal to length of 2 and 3 combined, articles 1 and 2 with about 5 ventral setal groups, article 3 with 3 setal groups; accessory flagellum about 5-articulate in male, 3-articulate in female. Antenna 2 setose, proximal flagellar articles with calceoli in male. Male gnathopod 1 propodus oval, palm oblique, concave, with median palmar spine and 2 or 3 angle spines. Male gnathopod 2 much larger than 1, propodus broadly oval, palm oblique, sinuous, with short median spine and 3 angle spines. Female gnathopod 1 propodus oval, palm oblique, convex, with 2 or 3 slender angle spines. Female gnathopod 2 propodus rectangular, palm almost transverse, convex, with 2 or 3 slender angle spines. Pereiopods 3 or 4 in male merus and carpus densely setose; pereiopods 5 to 7 in male with basal article broad, tapering distally, dactylus small, margins densely setose and robustly spinose. Pereiopods in female also short and stout but only sparsely setose. Uropods 1 and 2 peduncle outer margins setose. Uropod 3 outer ramus elongate, spinose and setose; smaller and less densely setose in female; inner ramus scale-like with few spines and setae. Telson lobes with lateral and apical spines and few long setae.
Male up to 9 mm, to about 5 mm in female.
White without markings.
Intertidal on clean shingle beaches; locally quite common; the only amphipod which is a permanent resident of this habitat.
Atlantic coast of Europe; Mediterranean.