Review on the distribution and biology of Antarctic Monoplacophora, with first abyssal record of Laevipilina antarctica

Records of extant Monoplacophora are still scarce, often limited to single specimens or empty shells. Little is known about monoplacophoran diversity, distribution and biology. This study summarizes the present distributional knowledge of all Antarctic monoplacophorans, adding new records from the Eastern Weddell Sea. The record of Laevipilina antarctica from over 3,000 m depth extends its previously known bathymetrical range from 210 to 644 m down to abyssal depths. Special symbiosis with bacteria might contribute to this remarkable eurybathy that is unique amongst extant monoplacophoran species. L. antarctica now is known from several stations along the shelf and slope of the Eastern Weddell and Lazarev Seas. Micropilina arntzi seems limited to the shelf and upper slope of the Lazarev Sea. An undescribed Laevipilina species is known only from a single station at the upper slope of the Eastern Weddell Sea. Distributional patterns are discussed and correlated to environmental conditions and available biological information.