King crabs of the western Atlantic sector of Antarctic and adjacent areas: new records, molecular barcode data and distribution (Crustacea: Decapoda: Lithodidae)

In many areas of the Antarctic and Subantarctic, king crabs records are still fragmentary. New data on the distribution of Lithodidae in the Scotia Sea and the adjacent area of the south-west Atlantic and the south-east Pacific have been collected during exploratory pot fishing in the year 2010 and are also based on some earlier collections that are deposited in Russian museums. The occurrence of Lithodes macquariae off Peter I Island is confirmed. Lithodes confundens, Lithodes turkayi and Neolithodes diomedeae were found in abundance on the Northern Scotia Ridge at a depth of, respectively, 315-775, 315-1,410 and 840-1,300 m. Paralomis formosa was recorded for the first time on the shelf of the South Orkney Islands, which is the southernmost record of this species. New material and literature data demonstrate the existence of two discontinuous lithodid faunas: the Antarctic Pacific fauna that extends up to the western Antarctic Peninsula and the Magellanic-Scotia fauna. The origin of this faunal discontinuity is discussed. The molecular barcodes (subunit I of the mitochondrial cytochrome-oxidase gene-COI) data for N. diomedeae and L. turkayi are provided for the first time. COI gene tree suggests that two main Subantarctic/Antarctic lineages of Lithodes, i.e. a pair Lithodes santolla/L. confundens and L. turkayi (with possibly closely related Lithodes murrayi and L. macquariae) are phylogenetically distant from each other as well as with low-latitude Pacific and Atlantic species of this genus.