Atyloella tribinicuspidata sp. n. (Crustacea, Amphipoda, Gammaridea, Eusiridae), a common amphipod in benthic communities off Bouvet Island (Southern Ocean)

Atyloella tribinicuspidata sp. n. was obtained and described from Agassiz trawl and dredging samples carried out in waters off Bouvet Island during the FS “Polarstern” ANT XXI/2 expedition in November 2003. Atyloella tribinicuspidata is a very common amphipod species characteristic of the deeper sublittoral, from 122 m to 134 m water depth. Atyloella tribinicuspidata is closely related to A. magellanicus Stebbing 1888, from the Magellan region of southernmost America. This allowed suggesting a speciation process within the genus, which is briefly discussed.