Rathke, 1837
Description
Rostrum straight or very slightly upcurved; seven to nine dorsal teeth, three ventral teeth (rarely two or four), tip often bifid. Three (occasionally two) of the dorsal teeth behind posterior edge of the orbit.
Carapace with antennal and branchiostegal spines. Antennules triramous; shorter ramus of the outer flagellum stout, about equal in length to peduncle and fused for about two-fifths of its length to longer ramus. Outer edge of stylocerite straight or very slightly concave; anterior border convex, becoming markedly concave adjacent to apical spine.
Scaphocerite extends to proximal half of propus of pereiopod 2 (maximum); apical spine not exceeding lamellar portion. Third maxilliped about 0.5 x length of scaphocerite; exopod present.
Mandible with incisor and molar process, and two-segmented palp. Dactyl of pereiopod one third the length of propus; carpus equal to or very slightly longer than merus.
Telson with two pairs of lateral spines.
Size
Length up to 63 mm.
Colour
Carapace and pleonites with dark yellow-brown bands. Rostrum colourless or with small red chromatophores. Legs with yellow and blue bands.
Ecology
This species may move offshore during winter in northern latitudes. Allen (1966a) noted this behaviour off the coast of Northumberland, but Forster (1951b) found little migration at Plymouth and Rodriguez and Naylor (1972) recorded no migration off the South Wales coast.
P. elegans is omnivorous, feeding on algae, small crustaceans and foraminiferans.
Ovigerous females occur from April-May to August-September. Many females produce two broods per season. The complete larval history of this species was given by Fincham (1977).
Depth range
Essentially a shore-dwelling species, frequently occurring in rock-pools around mid-tide level and sometimes higher. May also occur in shallow water close offshore.
Hyperbenthic species, may swim up at night; adults may get caught with pelagic sampling.
Distribution in the North Sea
All North Sea.
World distribution
Ranges from SW Norway to the coasts of SW Africa. Known also from the Baltic, Mediterranean, Black Sea, Caspian Sea and the Azores.
[mainly after Smaldon, 1993]