An exceptional occurrence of deep-sea sponges in the region of former Larsen Ice Shelves, Antarctic Peninsula, with the description of two new species

Abstract

Two new species of deep-sea sponges from the Weddell Sea are described. Both are new to science: a carnivorous Demospongiae species Abyssocladia antarctica sp. nov. and a Hexactinellida species Caulophacus leonieae sp. nov., the latter characterized by a new type of microscleres. Both were sampled at the former Larsen Ice Shelf region, Antarctic Peninsula, that was covered by ice until recent breakup events started in 1995. Abyssocladia Lévi, 1964 and Caulophacus Schulze, 1886 are well-known genera in the deep sea but were discovered here at only 200–300 m depths. The findings support the hypothesis that deep-sea and sub-shelf environments provide similar life conditions. These discoveries should urge us to further investigate areas of disintegrated Antarctic shelf ice as soon as possible, since new trophic conditions may have a severe impact on biodiversity and faunal composition.