Systematics and biogeography of marine gastropod molluscs from South Georgia

Abstract

The gastropod fauna of South Georgia is reviewed and a complete list of the 121 species known from the archipelago is provided; 65 species were re-examined upon the study of 3,048 specimens and reference specimens illustrated; other 56 species were included in the list from literature records. Iothia coppingeri (Smith, 1881), Submargarita unifilosa Thiele, 1912, Eumetula dilecta Thiele, 1912, Omalogyra burdwoodiana Strebel, 1908 and Newnesia antarctica Smith, 1902 are reported for the first time from South Georgia, and the presence of 16 species is confirmed by a second finding. Moreover, new bathymetric ranges for 30 species are given. The analysis of faunistic affinities of the gastropod fauna from South Georgia revealed a high similarity with South Orkney Islands (35 %), the Antarctic Weddell Sector (35 %) and South Shetland Islands (32 %). These data suggest the placement of the South Georgia in the Antarctic Region. However, the high number of gastropod species only known from South Georgia (53 species, 43 % of the total) and the distinctiveness of the composition of their assemblages, suggest that South Georgia should be considered as an own section within the Antarctic Region