king crab

The phylogeny of king crabs as hermit crabs who underwent secondary calcification and left their shell has been suspected since the late 1800s. They are believed to have originated during the Early Miocene in shallow North Pacific waters, where most king crab genera – including all Hapalogastrinae – are distributed and where they exhibit a high amount of morphological diversity.{{cite journal|last1=Karasawa|first1=Hiroaki|last2=Mizuno|first2=Yoshiaki|last3=Hachiya|first3=Kiichiro|last4=Ando|first4=Yusuke|title=Reappraisal of anomuran and brachyuran decapods from the lower Miocene Morozaki Group, Japan, collected by the Tokai Fossil Society|journal=Bulletin of the Mizunami Fossil Museum|date=March 2017|issue=43|pages=47–69|issn=0385-0900|url=https://www.city.mizunami.lg.jp/_res/projects/default_project/_page_/001/002/283/bmfm43karasawa-1.pdf|access-date=5 December 2024|via=the Mizunami Fossil Museum}}

In 2007, the king crabs were moved from their classification among the hermit crabs in the superfamily Paguroidea into a separate superfamily, Lithodoidea. This was 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; therefore, a separate superfamily in the classification poorly reflected the phylogenetic relationship of this taxon.{{cite journal |last1=Anker |first1=Arthur |last2=Paulay |first2=Gustav |date=2013-10-22 |title=A remarkable new crab-like hermit crab (Decapoda: Paguridae) from French Polynesia, with comments on carcinization in the Anomura |url=https://www.mapress.com/zootaxa/2013/f/zt03722p300.pdf|url-status=live |journal=Zootaxa |volume=3722 |issue=2 |pages=283–300 |doi=10.11646/zootaxa.3722.2.9 |archive-url=https://web.archive.org/web/20190724212126/https://www.mapress.com/zootaxa/2013/f/zt03722p300.pdf |archive-date=2019-07-24}} In 2023, king crabs were folded back into Paguroidea, with Lithodoidea being considered superseded.{{sfn|Poore|Ahyong|2023|pp=311–312}} The king crab's relationship to other hermit crabs as well as the family's internal phylogeny can be seen in the following two cladograms:{{cite journal |last1=Wolfe |first1=Joanna M. |last2=Breinholt |first2=Jesse W. |last3=Crandall |first3=Keith A. |last4=Lemmon |first4=Alan R. |last5=Lemmon |first5=Emily Moriarty |last6=Timm |first6=Laura E. |last7=Siddall |first7=Mark E. |last8=Bracken-Grissom |first8=Heather D. |display-authors=6 |date=24 April 2019 |title=A phylogenomic framework, evolutionary timeline and genomic resources for comparative studies of decapod crustaceans |journal=Proceedings of the Royal Society B |volume=286 |issue=1901 |doi=10.1098/rspb.2019.0079 |doi-access=free |pmid=31014217 |pmc=6501934}}

{{Anomura cladogram}}

{{Lithodidae cladogram}}

{{As of|2025|May}}, there are 15 known genera of king crabs across two subfamilies.{{Cite WoRMS|last=Ahyong|first=Shane T.|author-link=Shane T. Ahyong|year=2023|id=106737|title=Lithodidae Samouelle, 1819|access-date=18 May 2025}}{{sfn|Poore|Ahyong|2023|pp=311–312}}{{cite journal|last1=McLaughlin|first1=Patsy A.|last2=Komai|first2=Tomoyuki|last3=Lemaitre|first3=Rafael|last4=Rahayu|first4=Dwi Listyo|date=2010-10-31|editor-last=Low|editor-first=Martyn E. Y.|editor2=Tan|editor2-first=S. H.|title=Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea) Part I – Lithodoidea, Lomisoidea and Paguroidea|url=https://decapoda.nhm.org/pdfs/31605/31605.pdf|url-status=live|journal=The Raffles Bulletin of Zoology|volume=Suppl. 23|pages=5–107|archive-url=https://web.archive.org/web/20160417015104/https://decapoda.nhm.org/pdfs/31605/31605.pdf|archive-date=2016-04-17|via=the Natural History Museum of Los Angeles County}} These include:

{{Linked genus list

| Acantholithodes | Holmes, 1895

| Dermaturus | Brandt, 1850

| Hapalogaster | Brandt, 1850

| Oedignathus | Benedict, 1895

| Placetron | Schalfeew, 1892

}}

{{Linked genus list

| Cryptolithodes | Brandt, 1848

| Echidnocerus | White, 1842{{efn|name=de Grave & Ahyong 2022|Known as Lopholithodes Brandt, 1848 until 2022 after the senior synonym Echidnocerus was rediscovered.{{cite journal|last1=de Grave|first1=Sammy|last2=Ahyong|first2=Shane T.|author-link2=Shane T. Ahyong|title=Echidnocerus White, 1842, an overlooked senior synonym of Lopholithodes Brandt, 1848 (Decapoda, Lithodidae)|journal=Crustaceana|date=2022 |volume=95|issue=7|pages=861–865|doi=10.1163/15685403-bja10223|bibcode=2022Crust..95..861D |s2cid=252517428 }}}}

| Glyptolithodes | Faxon, 1895

| Lithodes | Latreille, 1806

| Neolithodes | A. Milne-Edwards & Bouvier, 1894

| Paralithodes | Brandt, 1848

| Paralomis | White, 1856

| Phyllolithodes | Brandt, 1848

| Rhinolithodes | Brandt, 1848

| Sculptolithodes | Makarov, 1934

}}

File:Neolithodes agassizii eating.jpg

King crabs are a morphologically diverse group, distinctive among hermit crabs for their superficial similarity to true crabs.{{Cite book|last=Ahyong|first=Shane T.|author-link=Shane T. Ahyong|url=https://docs.niwa.co.nz/library/public/Memoir%20123_The%20Marine%20Fauna%20of%20New%20Zealand_King%20Crabs.pdf#page=6|title=The Marine Fauna of New Zealand: King Crabs of New Zealand, Australia, and the Ross Sea (Crustacea: Decapoda: Lithodidae)|publisher=National Institute of Water and Atmospheric Research|year=2010|isbn=978-0478232851|series=NIWA Biodiversity Memoirs|volume=123|pages=5–15|lccn=2010497356|archive-url=https://web.archive.org/web/20200215075140/https://docs.niwa.co.nz/library/public/Memoir%20123_The%20Marine%20Fauna%20of%20New%20Zealand_King%20Crabs.pdf|archive-date=15 February 2020|url-status=live}} They have five pairs of legs, called pereopods:{{efn|These legs are commonly labeled pereopod 1–5 starting from the anterior.}} the first – frontmost – set are chelipeds whose right side is generally noticeably more robust than the left; the second, third, and fourth are walking legs tipped with sharp dactyli; and the fifth, used for cleaning, are very small and generally sit inside the branchial chamber. On their underside, they have a short abdomen – composed of plates – which is asymmetrical in females. This abdomen (sometimes called a pleon) is folded against the underside of the cephalothorax and is composed of six segments – called somites or pleonites – and a telson.{{sfn|Poore|Ahyong|2023|pp=885–886}}{{efn|These segments are commonly labeled somite/pleonite 1–6 starting from the posterior.}} In Hapalogastrinae, this abdomen is soft, while it is hard and calcified in members of Lithodinae. Lithodids lack any sort of uropod seen in some decapods.

King crabs are typically found in deep waters, especially in polar and subpolar regions and near hydrothermal vents and cold seeps.{{sfn|Poore|Ahyong|2023|p=311}} Members of Lithodinae can be found in all five of the world's oceans, namely the Pacific,{{sfn|Poore|Ahyong|2023|p=312}} Atlantic,{{sfn|Poore|Ahyong|2023|p=312}} Indian,{{Cite journal |last1=Hall |first1=Sally |last2=Thatje |first2=Sven |date=February 2018 |title=Evolution through cold and deep waters: the molecular phylogeny of the Lithodidae (Crustacea: Decapoda) |journal=The Science of Nature |volume=105 |issue=3–4 |page=19 |doi=10.1007/s00114-018-1544-2 |pmc=5829116 |pmid=29488024 |doi-access=free|bibcode=2018SciNa.105...19H }} Southern,{{sfn|Poore|Ahyong|2023|p=316}} and Arctic,{{Cite journal |last1=Dvoretsky |first1=Alexander G. |last2=Dvoretsky |first2=Vladimir G. |date=September 2013 |title=Population dynamics of the invasive lithodid crab, Paralithodes camtschaticus, in a typical bay of the Barents Sea |journal=ICES Journal of Marine Science |volume=70 |issue=6 |pages=1255–1262 |doi=10.1093/icesjms/fst037 |doi-access=free}} while members of Hapalogastrinae are only found in the North Pacific. Members of Hapalogastrinae exhibit a tolerance for higher temperatures than Lithodinae; whereas Lithodinae tend to live exclusively in deep waters or – less commonly – high-latitude shallow waters, Hapalogastrinae are found only in shallow waters (<{{convert|100|m|ft|abbr=on}}). At the deepest, members of the Lithodinae genera Paralomis, Neolithodes, and Lithodes have been found at depths of {{Convert|4152|m|ft|abbr=on}}, {{Convert|3207|m|ft|abbr=on}}, and {{Convert|1821|m|ft|abbr=on}}, respectively.{{sfn|Poore|Ahyong|2023|p=315–316}}

File:The Childrens Museum of Indianapolis - Alaskan red king crab.jpgs are widely fished in Alaska.]]

Because of their large size, the taste of their meat, and their status as a delicacy, some species of king crabs are caught and sold as food.{{cite journal|last1=Cocito|first1=Laura L.|last2=Permigiani|first2=Sabrina|last3=Tapella|first3=Federico|last4=Tomac|first4=Alejandra|last5=Czerner|first5=Marina|last6=Romero|first6=M. Carolina|title=Shelf-life of cooked meat of southern king crab (Lithodes santolla) and false king crab (Paralomis granulosa) during refrigerated storage|date=30 August 2024|journal=Heliyon|volume=10|issue=16|page=e36475|doi=10.1016/j.heliyon.2024.e36475|doi-access=free|pmid=39262967|pmc=11388567|bibcode=2024Heliy..1036475C }} Red (Paralithodes camtschaticus) and blue (Paralithodes platypus) king crabs are heavily targeted by commercial fisheries in Alaska and have been for several decades. However, populations have fluctuated in the past 25 years, and some areas are currently closed due to overfishing.{{cite journal|last1=Jensen|first1=Gregory C.|last2=Armstrong|first2=David A.|year=1989|title=Biennial reproductive cycle of blue king crab, Paralithodes platypus, at the Pribilof Island, Alaska and comparison to a congener, P. camtschatica|url=https://www.researchgate.net/publication/237183192|journal=Canadian Journal of Fisheries and Aquatic Sciences|volume=46|issue=6|pages=932–940|doi=10.1139/f89-120|bibcode=1989CJFAS..46..932J |issn=0706-652X|via=ResearchGate}}{{cite journal |last1=Klitin |first1=A.K. |last2=Nizyaev |first2=S.A. |year=1999 |title=The distribution and life strategies of some commercially important Far Eastern lithodid crabs in the Kuril Islands |journal=Biologiya Morya |location=Vladivostok |volume=25 |issue=3 |pages=221–228 |issn=1063-0740}}{{cite journal |last=Stevens |first=Bradley G. |date=October 2006 |title=Timing and duration of larval hatching for blue king crab Paralithodes platypus Brandt, 1850 held in the laboratory |journal=Journal of Crustacean Biology |volume=26 |issue=4 |pages=495–502 |doi=10.1651/S-2677.1 |jstor=4094179 |doi-access=free|bibcode=2006JCBio..26..495S }}{{cite report |url=http://www.fakr.noaa.gov/habitat/seis/final/Volume_II/Appendix_F.3.pdf |title=Essential fish habitat assessment report for the Bering Sea and Aleutian Islands King and Tanner Crabs |date=April 2005 |publisher=North Pacific Fishery Research Council |volume=II |at=Appendix F.3 |access-date=2009-12-06 |archive-url=https://web.archive.org/web/20100528050924/http://www.fakr.noaa.gov/habitat/seis/final/Volume_II/Appendix_F.3.pdf |archive-date=2010-05-28 |url-status=dead |series=NOAA Fisheries Report}} Alaskan fisheries additionally target the golden king crab (Lithodes aequispinus).{{cite journal|last1=Olson|first1=A.P.|last2=Siddon|first2=C.E.|last3=Eckert|first3=G.L.|date=March 2018|title=Spatial variability in size at maturity of golden king crab (Lithodes aequispinus) and implications for fisheries management|journal=Royal Society Open Science|volume=5|issue=3 |page=171802|doi=10.1098/rsos.171802|doi-access=free|pmid=29657785|pmc=5882709|bibcode=2018RSOS....571802O }} In South America, both the southern king crab (Lithodes santolla) and several species of Paralomis are targeted by commercial fisheries,{{sfn|Poore|Ahyong|2023|p=311}} and as a result, the population of L. santolla has seen a dramatic decline.{{Cite journal |last1=Anger |first1=Klaus |last2=Lovrich |first2=Gustavo A. |last3=Thatje |first3=Sven |last4=Calcagno |first4=Javier A. |date=August 2004 |title=Larval and early juvenile development of Lithodes santolla (Molina, 1782) (Decapoda: Anomura: Lithodidae) reared at different temperatures in the laboratory |url=https://www.researchgate.net/publication/223835464 |journal=Journal of Experimental Marine Biology and Ecology |volume=306 |issue=2 |pages=217–230 |doi=10.1016/j.jembe.2004.01.010 |bibcode=2004JEMBE.306..217A |via=ResearchGate}}

Juveniles of species of king crabs, including Neolithodes diomedeae, use a species (Scotoplanes Sp. A) of sea cucumber (often known as "sea pigs") as hosts and can be found on top of and under Scotoplanes. The Scotoplanes reduce the risk of predation for the N. diomedeae, while the Scotoplanes are not harmed from being hosts, which supports the consensus that the two organisms have a commensal relationship.{{Cite journal |last1=Barry |first1=James P. |last2=Taylor |first2=Josi R. |last3=Kuhnz |first3=Linda A. |last4=DeVogelaere |first4=Andrew P. |date=2016-10-15 |title=Symbiosis between the holothurian Scotoplanes sp. A and the lithodid crab Neolithodes diomedeae on a featureless bathyal sediment plain |journal=Marine Ecology |volume=38 |issue=2 |page=e12396 |doi=10.1111/maec.12396 |eissn=1439-0485}} Endosymbiotic microorganisms of the order Eccrinida have been found in Paralithodes camtschaticus and Lithodes maja, living in their hindgut between molts.{{cite journal|year=2018|last=Pavlova|first=L.V.|title=First Finding of Representatives of the Eccrinida Order in the Digestive Tract of King Crab Specie from the Barents Sea|journal=Doklady Biological Sciences|volume=483|issue=1 |issn=0012-4966|doi=10.1134/S0012496618060066|pmid=30603945|pages=231–234}}

Some species of king crab, including those of the genera Lithodes, Neolithodes, Paralithodes, and likely Echidnocerus, act as hosts to some parasitic species of careproctus fish.{{cite journal |last1=Gardner |first1=Jennifer |last2=Orr |first2=James |last3=Stevenson |first3=Duane |last4=Spies |first4=Ingrid |last5=Somerton |first5=David |title=Reproductive Parasitism between Distant Phyla: Molecular Identification of Snailfish (Liparidae) Egg Masses in the Gill Cavities of King Crabs (Lithodidae) |journal= Copeia|date=August 15, 2016 |volume=104 |issue=3 |pages=645–657 |url=https://bioone.org/journals/copeia/volume-104/issue-3/CI-15-374/Reproductive-Parasitism-between-Distant-Phyla--Molecular-Identification-of-Snailfish/10.1643/CI-15-374.short |access-date=October 19, 2021 |doi=10.1643/CI-15-374|s2cid=89241686 |url-access=subscription }} The careproctus lays eggs in the gill chamber of the king crab which serves as a well-protected and aerated area for the eggs to reside until they hatch. On occasion king crabs have been found to be host to the eggs of multiple species of careproctus simultaneously. King crabs are additionally parasitized by rhizocephalan genus Briarosaccus, a type of barnacle.{{Cite thesis |last=Noever |first=Christoph |title=Coevolution between king crabs (Paguridae: Lithodinae) and parasitic barnacles (Cirripedia: Rhizocephala) |date=27 January 2017 |access-date=15 October 2024 |degree=Doctoral |publisher=University of Bergen |url=https://bora.uib.no/bora-xmlui/handle/1956/16605}} The barnacle irreversibly sterilizes the crab, and over 50% of some king crab populations are affected.

• {{Portal-inline|Crustaceans}}
• {{Portal-inline|Marine life}}
• Alaskan king crab fishing

{{Notelist}}

{{Reflist}}

{{Refbegin}}

• {{Cite book |last1=Poore |first1=Gary C. B. |title=Marine Decapod Crustacea: A Guide to Families and Genera of the World |last2=Ahyong |first2=Shane T. |author-link2=Shane T. Ahyong |chapter=Anomura |pages=311–317 |publisher=CRC Press |year=2023 |isbn=978-1-4863-1178-1}}

{{Refend}}

• {{Cite book|editor-last=Stevens|editor-first=Bradley G.|title=King Crabs of the World: Biology and Fisheries Management|publisher=CRC Press|year=2014|isbn=978-1-4398-5542-3|doi=10.1201/b16664|edition=1st}}

• {{Wiktionary-inline|king crab}}

{{Lithodidae}}

{{Decapoda}}

{{Taxonbar|from=Q1861297}}

Category:Alaskan cuisine

Category:Edible crustaceans