Faunal diversity of the benthic amphipods (Crustacea) of the Magellan region as compared to the Antarctic (preliminary results)

To investigate the marine benthic ecosystems of the Magellan region and to compare them with the better known Antarctic systems, three campaigns were recently carried out in this area: the Joint Magellan "Victor Hensen" Campaign 1994, the "Polarstern" ANT XIII/4 cruise 1996, and the "Vidal Gormaz" CIMAR FIORDO II cruise 1996. Numerous and diverse zoobenthos samples were collected mostly with an Agassiz trawl and with a small dredge, an epibenthic sledge, with baited traps or by diving. All gears together gathered more than 132,000 specimens of gammaridean and caprellidean amphipods. 137 species of gammaridean amphipods have been identified from the material to date. About 20% of these species appear to be new for science. This taxonomic work takes place in the framework of a general revision of the Southern Ocean amphipod fauna undertaken by the "Antarctic Amphipodologists Network". A complete list of the benthic species of gammaridean and caprellidean amphipods is presented, including the zoogeographical distribution and the new records. The new abundant material collected, still under study, will allow a comparison of faunal diversity, zoogeographical and ecological traits of the Magellan benthic amphipod taxocoenoses with those of the West and East Antarctic benthos.