Novel distribution records of marine Tardigrada from abyssal sediments of the Northwest Atlantic Ocean

Four species of marine tardigrades were found in deep sea sediment samples of the Newfoundland Basin in the Northwest Atlantic Ocean. Samples were collected during expedition SO286 at more than 3000 m depth in an abyssal area that belongs to the intended new marine protected area “North Atlantic Current and Evlanov Seamount” (NACES). The genus Coronarctus was represented by two specimens of C. dissimilis. The genus Angursa was represented by four specimens of A. capsula, five specimens of A. abyssalis, and one specimen of A. lanceolata. In order to investigate the morphology and morphometry, we primarily used light microscopy with differential interference contrast. However, some specimens were additionally investigated with confocal laser scanning and scanning electron microscopy. The morphological and morphometric details and the new geographic records of the four identified species increase our knowledge of the taxonomy and biogeography of marine tardigrades. For C. dissimilis and A. lanceolata, the new records could indicate a pan-Atlantic distribution for both species, which were so far only known from the South Atlantic Ocean. The new record of A. capsula is even more remarkable since that species was so far only known from its type locality in the East Pacific deep sea.