The characters widely used for identifying members of the Ampelisca diadema group of species (A. diadema, A. spinipes, A. tenuicornis and A.armoricana) are reassessed. Highly variable characters are discarded in favour of more stable ones. Both sexes

The Ampeliscidae Kröyer, 1842 is amongst the most diverse amphipod families; it comprises four genera, Ampelisca being the richest with more than 200 species. The Ampelisca genus presents high morphological homogeneity and the identification of the

The genus Ampelisca comprises more than 150 species and is one of the more important benthic genus of marine amphipods. New species are regularly added (Barnard & Agard 1986; Bellan-Santini & Marques, 1986; Goeke, 1987). Ampelisca are found from the