Microarthridion corbisierae sp nov (Harpacticoida, Tachidiidae), a new meiofaunal copepod from the Northern coast of Sao Paulo State, Brazil

During studies on the diversity of meiobenthic marine harpacticoid copepods, a new representative of the family Tachidiidae was found on the inner continental shelf of Sao Paulo State, between Sao Sebastiao Channel and Ubatumirim Bay, Ubatuba (23 degrees 24'S, 44 degrees 57,6'W). Complementary material was collected near Enseada Beach, Ubatuba (23 degrees 30'S, 45 degrees 05'W). Although the new species shares with M. laurenticum (Nicholls, 1940) the reduced antennules, it can be easily distinguished from its congeners by leg 4 endopod with only two segments and the reduction of the number of inner setae of legs 1-4 endopod-3 and leg 3 exopod-3. Tachidiids, typically inhabiting fine sediments of brackish and marine shallow waters in the Northern Hemisphere, are good indicators of heavy organic pollution. This is the first record of the family Tachidiidae in the southern hemisphere.