First recorded occurrence of Cheirocratus robustus Sars, 1894 in the British Isles

Background Collections of the amphipod genus Cheirocratus from the North Sea and Ireland proved to include C. robustus Sars a species previously known only from Norway and Sweden. Results Material of C.robustus is described and figured from the Humber and Ireland together with the closely related species C. sundevalli (Rathke). A key to males of the Cheirocratus species of the North East Atlantic and Mediterranean is provided. Conclusions C. robustus is shown to be widespread in the eastern North Atlantic where it was previously overlooked.