Leach, 1814
Description:
Head smooth, domed and skull-shaped. Body stout, with varying numbers of small, paired dorsal tubercles on all segments except on 1; tubercles may be elongate in large specimens. Posterior regions of segments 2, 3 and 4 often with a single tubercle behind the pair. Maximum length 13 mm in male and 8 mm in female.
Antenna 1 about two-thirds of the body-length, sparsely covered with short setae, which are not arranged in parallel rows; flagellum of two articles. Mandible without palp.
Propodus of gnathopod 1 with a proximal spine. Gnathopod 2 inserted in the posterior third of the segment, often massive in large males; palm of propodus concave, with a proximal spine and a median tooth. In old and large males and females, segment 2 and gnathopod 2 may be covered in dense, fine setae.
Gills club-shaped, on segments 3 and 4 only.
Pereiopods 3 and 4 absent. Pereiopods 5, 6 and 7 with a pair of grasping spines on the propodus, and two to four accessory spines proximal to the grasping spines. Female gnathopod 2 inserted in the anterior half of the segment; anterior incubatory lamellae setose.
Abdomen with a pair of lobes and a pair of biarticulate appendages in male, in female without either.
Habitat:
Midshore level to sublittoral. Frequent in rock pools and gullies, on algae, hydroids and bryozoans.
Distribution:
Widely distributed in the North Sea, possibly more frequent in north.