Rathke, 1837
Description
Rostrum extending beyond tip of scaphocerite; straight, with five or six dorsal teeth (rarely four or seven) and three ventral teeth (rarely two or four); tip often bifid; one dorsal tooth behind posterior edge of orbit, the second often directly above the edge.
Carapace with antennal and branchiostegal spines. Antennules triramous, the shorter ramus of the outer flagellum normally exceeding the length of the peduncle and fused for one third of its length to the longer ramus. Outer edge of the stylocerite very slightly convex, anterior edge convex. Third maxilliped about 0.5 x length of scaphocerite; exopod present.
Mandible with molar and incisor process, and three-segmented palp. Dactyl of pereiopod 2 little over 2 x length of propus; carpus about 1.2 x length of merus.
Telson with two pairs of lateral spines.
Remarks
The dentition of the rostrum may vary considerably and Gutu (1971) has illustrated several forms. Deformities of Pereiopods 1 and 2 have been described by Heerebout (1969).
Size
Length up to 70 mm.
Colour
Usually a yellowish-grey, the carapace and pleon without the bands of pigment often found on other Palaemon species. Characteristic red pigment spots on lower half of rostrum.
Ecology
A shallow water species, often in estuarine conditions. Gravid females occur from May to August. The complete larval development has been described by Fincham (1985).
Depth range
Hyperbenthic species, may swim up at night, mostly confined to the nepheloid layer; adults may get caught with pelagic sampling. Down to about 0-10 m.
Distribution in the North Sea
Although this prawn is scarce around British shores, it occurs in large numbers off the Danish coast, where a thriving commercial fishery is based on this species (see Jensen, 1958a).
World distribution
Ranges from Norwegian coasts and Baltic Sea southwards to the Mediterranean, Black Sea, and Caspian Sea.
[mainly after Smaldon, 1993]