Eualus gaimardii

(Milne Edwards, 1837)

Description:
Rostrum curving upwards slightly, depth variable; twice length of antennular peduncle; five to seven dorsal teeth, three to five ventral teeth.
Carapace with antennal and pterygostomian spines.
Stylocerite acutely pointed, 0.66 x length of antennular peduncle or little more.
Scaphocerite about twice the length of antennular peduncle, outer border straight becoming concave towards apex; apical spine not exceeding lamellar portion. Third maxilliped equal to or slightly shorter than scaphocerite; epipod and exopod present.
Mandible with molar and incisor process, and two-segmented palp.
Pereiopods 1 and 2 with epipods, reduced setobranch on pereiopod 3. Carpus of pereiopod 2 seven-segmented. Pleonite 4 with acute ventro-posterior spine.
Telson with three to five pairs of lateral spines.

Remarks
The rostrum of this species varies considerably in shape and armature — illustrated by Dons (1915). Two forms of E. gaimardii were noted by Holthuis (1947). E. gaimardii forma gaimardii is a southern form with pleonite 3 smooth and rounded in both males and females. E. gaimardii forma belcheri (Bell, 1855) is a northern form, in which the posterior-median part of pleonite 3 in males bears a strong tubercle, which ends in a curved hook. The females have only a blunt, but distinct tubercle.

Size:
Length up to 100 mm, usually 60-70 mm.

Colour:
Pale, translucent, with brownish-red markings on carapace and pleon.

Habitat:
Down to about 10-200 metres. Hyperbenthic species, may swim up at night, mostly confined to the nepheloid layer. Ovigerous females occur from January to April, although the breeding period may be longer.

Distribution in the North Sea:
Adults reported from southwestern and northern North Sea, British NE coasts.

World distribution:
A circumpolar species, reaching its southern limits around northern Britain. It ranges from W Greenland, Jan Mayen, Spitzbergen, Franz Josef Land, N and W Norway, White Sea, Barents Sea, Siberia and Alaska southwards to Cape Cod (Massachusetts), the Firth of Forth and the Clyde Sea area.

%LABEL% (%SOURCE%)