Gammarus, FABRICIUS, 1775

Hou, Zhonge & Li, Shuqiang, 2010, Intraspecific or interspecific variation: delimitation of species boundaries within the genus Gammarus (Crustacea, Amphipoda, Gammaridae), with description of four new species, Zoological Journal of the Linnean Society 160 (2), pp. 215-253 : 223

GENUS GAMMARUS FABRICIUS, 1775

Diagnosis: Antenna 1 longer than antenna 2, primary flagellum longer than peduncle, accessory flagellum with more than two articles. Maxilla 1 with 11 apical spines on outer plate, palps asymmetric. Maxilla 2 with a diagonal row of plumose setae on inner plate. Gnothpods with one or more midspines on the palmar margin of propodus. Uropod 3 with two articles for outer ramus. Telson deeply cleft. Coxal gills present on gnathopod 2 and pereopods 3–7.

Remarks: Gammarus as one of the largest genera of Amphipoda , is widely distributed throughout the Northern Hemisphere. Most of the species are epigean freshwater taxa, with a few species reported from subterranean habitats and coastal marine waters. Barnard & Barnard (1983) reviewed the freshwater Amphipoda worldwide and 117 species were listed under the genus Gammarus . Since then, some regional works of the taxonomy of Gammarus have been undertaken, such as Gammarus species from Iran ( Khalaji-Pirbalouty & Sari, 2004) and a Gammarus list from Turkey ( Özbek & Balik, 2009). Up to now, more than 200 Gammarus species have been recorded ( Väinölä et al., 2008).