Bosc, 1802
Description
Body oblong. Cephalon subquadrate, with a marked transverse sinuous furrow behind the eyes. Eyes large and bulbous. Antenna 1 hardly extending beyond article 3 of the peduncle of antenna 2; antenna 2 robust, flagellum shorter than peduncle and about 1/6 the length of the body. Maxillipedal palp of four articles. Coxal plates triangular, extending over the whole length of the segment in pereion segments 2 or 3 to 7; segments 5 to 7 sharply produced laterally. Pereiopods all more or less alike. Pleon of two complete segments, and one partial suture in the pleotelson. Pleotelson with the sides and posterior border straight. Uropods uniramous.
Colour is uniformly greyish or brown.
Size
Length in males recognisable from about 8 mm, ranging to about 30 mm; females from 9 to 18 mm.
Depth range/habitat
Surface dweller, among floating weed, timber and colonies of Lepas (Subclass Cirripedia, Barnacles).
Distribution
This species occasionally reaches the North Sea from the east coast of North America, carried by the Gulf Stream and North Atlantic Drift.
World distribution
Oceanic, warmer waters.
Remark
This oceanic, warm water species was reported from plankton catches made from the former Dutch Texel Lightship in the S North Sea (Van der Baan and Holthuis, 1969a). Later, the species has been reported from the German Bight off Helgoland as a recent invader and as a possible indicator species for warming of the southern North Sea (Franke et al., 1999).