Two new species of the genus Austroniscus Vanhoeffen, 1914 (Isopoda: Asellota: Nannoniscidae) from the Antarctic shelf

During the BENDEX expedition (BENthic Disturbance-EXperiment) with RV Polarstern in Antarctic summer 2003/04, species of the genus Austroniscus Vanhoeffen, 1914 were sampled from the continental shelf of the eastern Weddell Sea. Besides Austroniscus ovails Vanhoeffen, 1914, which is the first record of this species from western Antarctica, two other species were found, i.e. Austroniscus chelus sp. nov. and Austroniscus obscurus sp. nov. They both bear many resemblances to Austroniscus ovails, but can be easily distinguished from A. ovails by the shape of the rostral crest and the first pereonite. The two new species are very similar to each other but differ in the number of articles of the antennula and the shape of pleopods 3 to 5.