King crabs are a taxon of decapod crustaceans chiefly found in cold seas. Because of their large size and the taste of their meat, many species are widely caught and sold as food, the most common being the red king crab (Paralithodes camtschaticus). King crabs are generally thought to be derived from hermit crab ancestors within the Paguridae, which may explain the asymmetry still found in the adult forms. This ancestry is supported by several anatomical peculiarities which are present only in king crabs and hermit crabs. Although some doubt still exists about this hypothesis, king crabs are the most widely quoted example of carcinisation among the Decapoda. The evidence for this explanation comes from the asymmetry of the king crab's abdomen, which is thought to reflect the asymmetry of hermit crabs, which must fit into a spiral shell. Controversial taxon Although formerly classified among the hermit crabs in the superfamily Paguroidea, king crabs are now placed in a separate superfamily, Lithodoidea. This is not without controversy, as there is widespread consensus in the scientific community that king crabs are derived from hermit crabs and closely related to pagurid hermit crabs, and therefore a separate superfamily in the classification poorly reflects the phylogenetic relationship of this taxon. Species Around 121 species are known, in 10 genera: Cryptolithodes Brandt, 1848 Cryptolithodes expansus Miers, 1879 Cryptolithodes sitchensis Brandt, 1853 – umbrella crab Cryptolithodes typicus Brandt, 1848 – butterfly crab Glyptolithodes Faxon, 1895 Glyptolithodes cristatipes (Faxon, 1893) Lithodes Latreille, 1806 Lithodes aequispinus J. E. Benedict, 1895 – golden king crab or brown king crab Lithodes aotearoa Ahyong, 2010 Lithodes australiensis Ahyong, 2010 Lithodes ceramensis Takeda & Nagai, 2004 Lithodes chaddertoni Ahyong, 2010 Lithodes confundens Macpherson, 1988 Lithodes couesi J. E. Benedict, 1895 – scarlet king crab Lithodes ferox Filhol, 1885 Lithodes formosae Ahyong & Chan, 2010 Lithodes galapagensis Hall & Thatje, 2009 Lithodes jessica Ahyong, 2010 Lithodes longispina Sakai, 1971 Lithodes macquariae Ahyong, 2010 Lithodes maja (Linnaeus, 1758) – Norway king crab or trollkrabbe Lithodes mamillifer Macpherson, 1988d Lithodes mandtii Lithodes manningi Macpherson, 1988 Lithodes megacantha Macpherson, 1991 Lithodes murrayi Henderson, 1888 Lithodes nintokuae Sakai, 1976 Lithodes panamensis Faxon, 1893 Lithodes paulayi Macpherson & Chan, 2008 Lithodes rachelae Ahyong, 2010 Lithodes richeri Macpherson, 1990 Lithodes robertsoni Ahyong, 2010 Lithodes santolla (Molina, 1782) – Chilean centolla or Chilean king crab Lithodes turkayi Macpherson, 1988 Lithodes turritus Ortmann, 1892 Lithodes unicornis Macpherson, 1984 Lithodes wiracocha