Inachus phalangium

Large males may reach a carapace size of {{convert|20.5|x|17.5|mm|1}}, and is brownish-yellow in colour. The carapace becomes narrower towards the front of the animal, and is often concealed by epibionts.{{cite web |url=http://nlbif.eti.uva.nl/bis/crustacea.php?menuentry=soorten&id=200 |title=Inachus phalangium |work=Macrobenthos of the North Sea: Crustacea |author1=M. J. de Kluiver |author2=S. S. Ingalsuo |publisher=Universiteit van Amsterdam |accessdate=February 18, 2011 |archive-url=https://web.archive.org/web/20110724172028/http://nlbif.eti.uva.nl/bis/crustacea.php?menuentry=soorten&id=200 |archive-date=July 24, 2011 |url-status=dead }} I. phalangium resembles the closely related species Inachus dorsettensis, but has less prominent spines on the carapace.

Inachus phalangium is found in the eastern Atlantic Ocean, from Norway in the north to West Africa and the Cape Verde islands in the south, and extending into the Mediterranean Sea.{{cite book |editor1=P. J. Hayward |editor2=John Stanley Ryland |year=1995 |title=Handbook of the Marine Fauna of North-west Europe |publisher=Oxford University Press |isbn=978-0-19-854055-7 |author1=P. J. Hayward |author2=M. J. Isaac |author3=P. Makings |author4=J. Moyse |author5=E. Naylor |author6=G. Smaldon |chapter=Crustaceans |pages=289–461 |chapter-url=https://books.google.com/books?id=sZ8mdRT4jbIC&pg=PA447}} It lives at depths of {{convert|11|-|55|m|-1}}.

File:AnemoneDeMer.JPG, Anemonia sulcata]]

Inachus phalangium lives commensally with the sea anemone Anemonia sulcata (snakelocks anemone).{{cite journal |author1=Peter Wirtz |author2=Rudolf Diesel |year=1983 |title=The social structure of Inachus phalangium, a spider crab associated with the sea anemone Anemonia sulcata |journal=Zeitschrift für Tierpsychologie |volume=62 |issue=3 |pages=209–234 |doi=10.1111/j.1439-0310.1983.tb02152.x}} The crab gains protection from potential predators by sheltering beneath the anemone's stinging tentacles.{{cite journal |author=Rudolf Diesel |year=1988 |title=Male-female association in the spider crab Inachus phalangium: the influence of female reproductive stage and size |journal=Journal of Crustacean Biology |volume=8 |issue=1 |pages=63–69 |doi=10.1163/193724088X00080 |jstor=1548431 |bibcode=1988JCBio...8...63. }} The crab eats particles of food dropped by the sea anemone, and mucus from the surface of the anemone.{{cite journal |author1=L. G. Jonsson |author2=T. Lundälv |author3=K. Johannesson |year=2001 |title=Symbiotic associations between anthozoans and crustaceans in a temperate coastal area |journal=Marine Ecology Progress Series |volume=209 |pages=189–195 |doi= 10.3354/meps209189|url=https://www.int-res.com/articles/meps/209/m209p189.pdf |doi-access=free |bibcode=2001MEPS..209..189J }}

The earliest scientific description of Leach's spider crab may have been Carl Linnaeus' description of "Cancer tribulus" in the 12th edition of his Systema Naturae in 1767. Linnaeus' description was, however, too vague to allow the species to be confidently identified.{{cite journal |author=L. B. Holthuis |author-link=Lipke Holthuis |year=1962 |title=Arctopsis Lamarck, 1801 (Crustacea, Decapoda); proposed suppression under the plenary powers, and related matters |journal=Bulletin of Zoological Nomenclature |volume=19 |issue=3 |pages=184–188 |url=https://www.biodiversitylibrary.org/page/12221057}} That name is therefore a nomen dubium, and it was suppressed by the International Commission on Zoological Nomenclature in 1964 at the request of Lipke Holthuis.{{cite journal |author=International Commission on Zoological Nomenclature |author-link=International Commission on Zoological Nomenclature |year=1964 |title=Opinion 708. Arctopsis Lamarck, 1801 (Crustacea, Decapida): suppressed under the plenary powers |journal=Bulletin of Zoological Nomenclature |volume=21 |issue=3 |pages=208–209 |url=https://www.biodiversitylibrary.org/page/12222061}} The first valid description was Johan Christian Fabricius' publication of the name Cancer phalangium in his 1775 work Systema Entomologiae. The name Cancer phalangium was later protected by being placed on the Official List of Specific Names in Zoology.{{cite journal |author=International Commission on Zoological Nomenclature |author-link=International Commission on Zoological Nomenclature |year=1966 |title=Opinion 763. Stenorhynchus Lamarck, 1818 (Crustacea, Decapoda): validated under the plenary powers with designation of Cancer seticornis Herbst, 1788, as type-species |journal=Bulletin of Zoological Nomenclature |volume=23 |issue=1 |pages=19–21 |url=https://www.biodiversitylibrary.org/page/12222820}}

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{{Reflist|2}}

• {{cite journal |author=R. Diesel |year=1986 |title=Population dynamics of the commensal spider crab Inachus phalangium (Decapoda: Maiidae) |journal=Marine Biology |volume=91 |issue=4 |pages=481–489 |doi=10.1007/BF00392599|bibcode=1986MarBi..91..481D |s2cid=84557796 }}
• {{cite journal |author1=G. Weinbauer |author2=V. Nussbaumer |author3=R. A. Patzner |year=1982 |title=Studies on the relationship between Inachus phalangium Fabricius (Maiidae) and Anemonia sulcata Pennant in their natural environment |journal=Marine Ecology |volume=3 |issue=2 |pages=143–150 |doi=10.1111/j.1439-0485.1982.tb00379.x|bibcode=1982MarEc...3..143W }}
• {{cite journal |author1=Rocco Rorandelli |author2=Marina Gomei |author3=Marco Vannini |author4=Stefano Cannicci |year=2007 |title=Feeding and masking selection in Inachus phalangium (Decapoda, Majidae): dressing up has never been so complicated |journal=Marine Ecology Progress Series |volume=336 |pages=225–233 |doi=10.3354/meps336225|doi-access=free |bibcode=2007MEPS..336..225R |hdl=2158/204944 |hdl-access=free }}

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Category:Majoidea

Category:Crabs of the Atlantic Ocean

Category:Crustaceans described in 1775

Category:Taxa named by Johan Christian Fabricius