AN ACCOUNT OF THE MYSIDACEA (CRUSTACEA, MALACOSTRACA) OF THE SOUTHERN-OCEAN

An inventory of Antarctic and Subantarctic mysid fauna is presented, t ogether with a summary of the present state of knowledge of species an d their taxonomic diversity, geographic and bathymetric distribution p atterns. Fifty nine species of Mysidacea (Crustacea, Peracarida) are n ow known. Of these, 37 were reported for the Antarctic region and 31 f or the Magellan region; six species occur further north in the Souther n Ocean, but south of 40 degrees S. 51% of the Antarctic Mysidacea are endemic, and the figure for the Magellan region is 48%. Most of the s pecies live hyperbenthically, but some also occur bathy- or mesopelagi cally. Mysidetes has the most species in the Southern Ocean, and Eucop ia australis is the species with the widest bathymetric distribution ( 600-6000 m depth). It is concluded that an emergence of species onto t he Antarctic shelf in the Neogene was quite unlikely, because none of the mysid species is a true deepsea species, and most species occur on the shelf or at the shelf break. It is more probable that present day species colonized the Southern Ocean via shallower waters. The exampl es of the distribution of different genera suggest that the Mysidacea of the Southern Ocean probably had various geographical origins.