Paralomis

Paralomis is a widely distributed, highly speciose, and morphologically diverse genus of king crabs in the subfamily Lithodinae.^[2][3]

Paralomis
Paralomis granulosa
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Anomura
Family:	Lithodidae
Subfamily:	Lithodinae
Genus:	Paralomis White, 1856[1]
Type species
Paralomis granulosa (Hombron & Jacquinot, 1846)
Synonyms[2]
Acantholithus Stimpson, 1858 Leptolithodes Benedict, 1895 Pristopus Benedict, 1895

Description

Like all king crabs, Paralomis has evolved a crab-like appearance through a process called carcinisation.^[3] Paralomis has either a pentagonal or pyriform carapace.^[3] At the very front, its rostrum consists of one short, conical spine projecting forward in the middle and one or more pairs of spines angled upward around the base.^[3][4] Like all king crabs, the gastric region, directly behind the rostrum, is elevated above the others.^[3] Like Lithodes and Neolithodes, the cardiac region – directly behind the gastric region, separated by a deep groove – is triangular.^[3] Its three pairs of walking legs – morphologically similar, with the middle pair typically being the longest – are not covered at their bases by the carapace.^[3] In adults, the undersides of the dactyli feature horn-like spines.^[3] The abdomen is more calcified than in other king crab genera: the second segment is undivided, the third segment has fused submedian and marginal (outer) plates, and segments three, four, and five are all entirely calcified.^[3]

Distribution

Paralomis is present in four of Earth's five oceans – namely the Atlantic, Pacific, Indian, and Southern – as well as all seven continents.^[3] They are found from the very shallow intertidal zone to the deep, perpetually dark abyssal zone.^[4] The deepest known species of Paralomis is P. bouvieri, which has been discovered living at 4,152 m (13,622 ft).^[3]

Taxonomy

Paralomis was described in 1856 by zoologist Adam White and named for its similarity to the genus Lomis.^[1] In 1895, marine biologist James Everard Benedict incorrectly placed Paralomis granulosa, the genus' type species, under the genus Lithodes.^[5][3] Benedict therefore dissolved the genus and created two now-defunct ones – Leptolithodes and Pristopus – for other members of Paralomis.^[5][3] Paralomis is closely related to Echidnocerus, and the monospecific genus Glyptolithodes – nested cladistically inside Paralomis – may simply be a species of Paralomis.^[6][7][8]

Paralomis contains over 70 species – more than any other king crab genus – and is the most morphologically diverse genus in the subfamily Lithodinae.^[3][4] It contains one fossil species, Paralomis debodeorum, which lived in New Zealand in the Middle–Late Miocene.^[3] Paralomis is distinguished from other king crabs by its abdominal segments: the second is undivided, and the third, fourth, and fifth are entirely calcified.^[3] Current scientific consensus is that Paralomis is monophyletic, although within this group, carcinologist Shane T. Ahyong in 2010 identified several informal subgroups of Paralomis.^[3] Paralomis' relationship to other king crabs can be seen in the following cladogram:^[6]

Lithodidae cladogram

Lithodidae Paralithodes brevipes Paralomis/Glyptolithodes Glyptolithodes cristatipes Paralomis zealandica Paralomis granulosa Paralomis dofleini Paralomis pacifica Paralomis birsteini Paralomis cristata Paralomis formosa Paralomis multispina Paralomis hirtella Paralomis spinosissima Paralomis erinacea Paralomis africana Paralomis cristulata Paralomis anamerae Paralomis aculeata Paralomis elongata Echidnocerus Echidnocerus cibarius Echidnocerus foraminatus Neolithodes Neolithodes diomedeae Neolithodes brodiei Neolithodes grimaldii Neolithodes duhameli Neolithodes asperrimus Lithodes Lithodes nintokuae Lithodes turkayi Lithodes longispina Lithodes murrayi Lithodes aequispinus Lithodes couesi Lithodes turritus Lithodes paulayi Lithodes ferox Lithodes maja Lithodes santolla Lithodes confundens Paralithodes platypus Paralithodes camtschaticus Phyllolithodes/Rhinolithodes Phyllolithodes papillosus Rhinolithodes wosnessenskii Acantholithodes hispidus Placetron wosnessenskii Cryptolithodes Cryptolithodes sitchensis Cryptolithodes typicus Hapalogaster Hapalogaster mertensii Hapalogaster grebnitzkii Hapalogaster dentata Oedignathus inermis

Species

Paralomis contains the following species:^[2]

Image	Scientific name	Common name	Distribution
	Paralomis aculeata Henderson, 1888		Southwest Indian Ridge
	Paralomis africana Macpherson, 1982		Namibia
	Paralomis alcockiana Hall & Thatje, 2009
	Paralomis alis Ahyong, 2020
	Paralomis anamerae Macpherson, 1988		Argentina, Crozet Island, South Georgia Island
	Paralomis arae Macpherson, 2001
	Paralomis arethusa Macpherson, 1994
	Paralomis aspera Faxon, 1893
	Paralomis birsteini Macpherson, 1988		Southern Ocean near Scott Island
	Paralomis bouvieri Hansen, 1908
	Paralomis ceres Macpherson, 1989
	Paralomis chilensis Andrade, 1980
	Paralomis cristata Takeda & Ohta, 1979
	Paralomis cristulata Macpherson, 1988
	Paralomis cubensis Chace, 1939
	Paralomis danida Takeda & Bussarawit, 2007
	Paralomis dawsoni Macpherson, 2001		New Caledonia, northern New Zealand, and the Solomon Islands
	Paralomis debodeorum Feldmann, 1998 †		New Zealand (Middle–Late Miocene)
	Paralomis diomedeae (Faxon, 1893)
	Paralomis dofleini Balss, 1911
	Paralomis echidna Ahyong, 2010
	Paralomis elongata Spiridonov, Turkay, Arntz & Thatje, 2006
	Paralomis erinacea Macpherson, 1988
	Paralomis formosa Henderson, 1888
	Paralomis gowlettholmes Ahyong, 2010
	Paralomis granulosa (Hombron & Jacquinot, 1846)	False king crab, Chilean snow crab	Chile, Argentina, Falkland Islands
	Paralomis grossmani Macpherson, 1988
	Paralomis haigae Eldredge, 1976
	Paralomis hirtella de Saint Laurent & Macpherson, 1997		Lau Basin, North Fiji Basin
	Paralomis histrix (De Haan, 1849)		Japan (Tokyo Bay to Kyūshū)
	Paralomis hystrixoides Sakai, 1980
	Paralomis inca Haig, 1974
	Paralomis indica Alcock & Anderson, 1899
	Paralomis investigatoris Alcock & Anderson, 1899
	Paralomis jamsteci Takeda & Hashimoto, 1990
	Paralomis japonica Balss, 1911
	Paralomis kyushupalauensis Takeda, 1985
	Paralomis longidactylus Birstein & Vinogradov, 1972
	Paralomis longipes Faxon, 1893
	Paralomis macphersoni Muñoz & García-Isarch, 2013
	Paralomis makarovi Hall & Thatje, 2009
	Paralomis manningi Williams, Smith & Baco, 2000	Deep-sea spider crab	West Coast of the United States
	Paralomis medipacifica Takeda, 1974
	Paralomis mendagnai Macpherson, 2003
	Paralomis microps Filhol, 1884
	Paralomis multispina (Benedict, 1895)
	Paralomis nivosa Hall & Thatje, 2009
	Paralomis ochthodes Macpherson, 1988		Indonesia (Gulf of Boni)
	Paralomis odawarai (Sakai, 1980)
	Paralomis okitoriensis Takeda, 2019		Okinotorishima
	Paralomis otsuae Wilson, 1990
	Paralomis pacifica Sakai, 1978
	Paralomis papillata (Benedict, 1895)
	Paralomis papua Ahyong, 2020
	Paralomis pectinata Macpherson, 1988
	Paralomis phrixa Macpherson, 1992
	Paralomis poorei Ahyong, 2010
	Paralomis roeleveldae Kensley, 1981
	Paralomis seagranti Eldredge, 1976
	Paralomis serrata Macpherson, 1988
	Paralomis sonne Guzmán, 2009
	Paralomis spectabilis Hansen, 1908		Eastern Greenland, Iceland
	Paralomis spinosissima Birstein & Vinogradov, 1972
	Paralomis staplesi Ahyong, 2010		Tasman Fracture, Tonga–Kermadec Ridge
	Paralomis stella Macpherson, 1988
	Paralomis stevensi Ahyong & Dawson, 2006
	Paralomis taylorae Ahyong, 2010
	Paralomis truncatispinosa Takeda & Miyake, 1980		East China Sea, Taiwan
	Paralomis tuberipes Macpherson, 1988		Chile (Puerto Aguirre [es])
	Paralomis verrilli (Benedict, 1895)
	Paralomis webberi Ahyong, 2010		New Zealand
	Paralomis zealandica Dawson & Yaldwyn, 1971	Prickly king crab	New Zealand

References

1. White, Adam (1856). "Some remarks on Crustacea of the genus Lithodes, with a brief description of a species apparently hitherto unrecorded". Proceedings of the Zoological Society of London: 132–135. Retrieved 29 November 2024.
2. Ahyong, Shane T. (12 December 2023). "Paralomis White, 1856". WoRMS. World Register of Marine Species. Retrieved 21 October 2024.
3. Ahyong, Shane T. (2010). The Marine Fauna of New Zealand: King Crabs of New Zealand, Australia, and the Ross Sea (Crustacea: Decapoda: Lithodidae) (PDF). NIWA Biodiversity Memoirs. Vol. 123. National Institute of Water and Atmospheric Research. pp. 108–110. ISBN 978-0478232851. LCCN 2010497356. Archived (PDF) from the original on 15 February 2020.
4. Poore, Gary C. B.; Ahyong, Shane T. (2023). "Anomura". Marine Decapod Crustacea: A Guide to Families and Genera of the World. CRC Press. pp. 311–317. ISBN 978-1-4863-1178-1.
5. Benedict, James Everard (1895). "Descriptions of new genera and species of crabs of the family LIthodidæ, with notes on the young of Lithodes camtschaticus and Lithodes brevipes". Proceedings of the United States National Museum. 17: 479–488. Retrieved 30 November 2024 – via the Internet Archive.
6. Noever, Christoph; Glenner, Henrik (2017-07-05). "The origin of king crabs: hermit crab ancestry under the magnifying glass" (PDF). Zoological Journal of the Linnean Society. 182 (2): 300–318. doi:10.1093/zoolinnean/zlx033. Archived (PDF) from the original on 2019-07-16 – via the University of Copenhagen.
7. Hall, Sally; Thatje, Sven. "Evolution through cold and deep waters: the molecular phylogeny of the Lithodidae (Crustacea: Decapoda)". The Science of Nature. 105. article 19. Bibcode:2018SciNa.105...19H. doi:10.1007/s00114-018-1544-2. PMC 5829116. PMID 29488024.
8. Macpherson, Enrique (May 1988). "Revision of the family Lithodidae Samouelle, 1819 (Crustacea: Decapoda: Anomura) in the Atlantic Ocean" (PDF). Monografías de Zoología Marina. II: 23. ISSN 0213-4020. Archived (PDF) from the original on May 14, 2020 – via the Natural History Museum of Los Angeles County.

External links

• Media related to Paralomis at Wikimedia Commons
• Data related to Paralomis at Wikispecies