Ascidians collected during the Spanish Antarctic expedition CIEMAR 99/00 in the Bransfield and Gerlache Straits

During the Spanish expedition CIEMAR 99/00, on board the BIO‐Hespérides, 30 species of ascidians (distributed in 13 genera and eight families) were collected using a rock dredge in the Bransfield and Gerlache straits. Most of them were already known, but one species, Tetrazona ciemari sp. nov., is new for science. Additional morphological data are provided for six species. Five are reported for only the second time and the known distributions of five species are extended.