The Majoidea are a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s which includes the various spider crabs.

Taxonomy

In "''A classification of living and fossil genera of decapod crustaceans''" De Grave and colleagues divided Majoidea into six families: * Family

Epialtidae Epialtidae is a family of crabs, containing the subfamilies: * Epialtinae MacLeay, 1838 * Pisinae Pisinae is a subfamily of crabs in the family Epialtidae, comprising the following genera: * '' Acanthophrys'' A. Milne-Edwards, 1865 * '' Ana ...

** Subfamily

Epialtinae Epialtinae is a subfamily of crabs, containing the following genera: * ''Acanthonyx'' Latreille, 1828 * '' Alfredalcockia'' Števčić, 2005 * '' Antilibinia'' MacLeay, 1838 * '' Cyclonyx'' Miers, 1879 * '' Epialtoides'' Garth, 1958 * '' Epialt ...

** Subfamily

Pisinae Pisinae is a subfamily of crabs in the family Epialtidae, comprising the following genera: * '' Acanthophrys'' A. Milne-Edwards, 1865 * '' Anamathia'' Smith, 1885 * '' Apias'' Rathbun, 1897 * '' Apiomithrax'' Rathbun, 1897 * '' Austrolibinia'' G ...

** Subfamily Pliosomatinae ** Subfamily Tychiinae * Family

Hymenosomatidae Hymenosomatidae is a family of crabs with some 110 described species in nearly 20 genera. The following genera are placed in the Hymenosomatidae: *'' Amarinus'' *'' Apechocinus'' *'' Cancrocaeca'' *'' Crustaenia'' *'' Elamena'' *'' Elamenopsis ...

* Family

Inachidae Inachidae is a family of crabs, containing 39 genera: *'' Achaeopsis'' Stimpson, 1857 *'' Achaeus'' Leach, 1815 *'' Anisonotus'' A. Milne-Edwards, 1879 *'' Anomalothir'' Miers, 1879 *'' Bothromaia'' Williams & Moffitt, 1991 *'' Calypsachaeus'' ...

* Family

Inachoididae Inachoididae is a family of crabs originally erected by James Dwight Dana James Dwight Dana FRS FRSE (February 12, 1813 – April 14, 1895) was an American geologist, mineralogist, volcanologist, and zoologist. He made pioneering studies of m ...

* Family

Majidae Majidae is a family of crabs, comprising around 200 marine species inside 52 genera, with a carapace that is longer than it is broad, and which forms a point at the front. The legs can be very long in some species, leading to the name "spider c ...

** Subfamily Eurynolambrinae ** Subfamily Majinae ** Subfamily Micromaiinae ** Subfamily Mithracinae ** Subfamily Planoterginae * Family

Oregoniidae The Oregoniidae are a family of crabs, formerly included in the family Majidae. It contains the four genera ''Chionoecetes'', ''Hyas Hyas ( grc, Ὑάς, Hūás, ; ), in Greek mythology, was a Boeotian who was regarded as the ancestor of the a ...

The classification has since been revised, with subfamilies Epialtinae and Mithracinae being elevated to families and Hymenosomatidae being moved to its own superfamily. The family composition according to the

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ...

is as follows: * family

MacLeay, 1838 * family

Dana, 1851 * family Macrocheiridae Dana, 1851 * family

Samouelle, 1819 – "true" spider crabs * family

Mithracidae Mithracidae is a family of crustaceans belonging to the order Decapoda. Genera Genera: *''Ala'' *'' Amphithrax'' *''Hemus'' *'' Maguimithrax'' *'' Microphrys'' *'' Mithraculus'' *'' Mithrax'' *'' Nemausa'' *'' Nonala'' *'' Omalacantha ...

Balss, 1929 * family

Garth, 1958 * family Priscinachidae Breton, 2009 Notable species within the superfamily include: * Japanese spider crab (''Macrocheira kaempferi''), the largest living species of crab, found on the bottom of the Pacific Ocean. * ''

Libinia emarginata ''Libinia emarginata'', the portly spider crab, common spider crab or nine-spined spider crab, is a species of stenohaline crab that lives on the Atlantic coast of North America. Distribution ''Libinia emarginata'' occurs from Nova Scotia to th ...

'', the ''portly spider crab'', a species of crab found in estuarine habitats on the east coast of North America. * ''

Hyas Hyas ( grc, Ὑάς, Hūás, ; ), in Greek mythology, was a Boeotian who was regarded as the ancestor of the ancient Hyantes (Boeotians). His name means rain from ''hyô, hyetos.'' Family Hyas was the son of the Titan Atlas and either of the ...

'', a genus of spider crabs, including the great spider crab (''Hyas araneus''), found in the Atlantic and the North Sea. * '' Maja squinado'', sometimes called the "European long leg crab or pie faced crab" because of the way its face is shaped. * ''

Australian majid spider crab Australian(s) may refer to: Australia * Australia, a country * Australians, citizens of the Commonwealth of Australia ** European Australians ** Anglo-Celtic Australians, Australians descended principally from British colonists ** Aboriginal Au ...

'', found off Tasmania, are known to pile up on each other, the faster-moving crabs clambering over the smaller, slower ones. There is one fossil family, Priscinachidae, represented by a single species, '' Priscinachus elongatus'', from the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

of France. Image:Candy crab.jpg, ''

Hoplophrys oatesi ''Hoplophrys'' is a monotypic genus of crab in the Family (biology), family Epialtidae. It contains the single species Hoplophrys oatesi, also known as the candy crab, Oates's soft coral crab, commensal soft coral crab and ''Dendronephthya'' cr ...

'', an

Image:Limnopilos naiyanetri - (4).jpg, ''

Limnopilos naiyanetri ''Limnopilos naiyanetri'', commonly referred to as the Thai micro crab or pill-box crab, is a freshwater hymenosomatid crab endemic to Thailand. Its presence has only been confirmed in the Tha Chin River. The species was described in 1991 and r ...

'', a

Image:Macrocheira kaempferi.jpg, ''

Macrocheira kaempferi The Japanese spider crab (''Macrocheira kaempferi'') is a species of marine crab that lives in the waters around Japan. It has the largest known leg-span of any arthropod. It goes through three main larval stages along with a prezoeal stage to ...

'', an

Image:Pyromaia cuspidata.jpg, ''

Pyromaia cuspidata ''Pyromaia cuspidata'', also known as the dartnose pear crab, is a species of crab in the family Inachoididae. This crab appears similar to ''Anasimus latus''. It is a long-legged crab with a trident-shaped rostrum, and occurs in Atlantic waters ...

'', an

Image:Maja squinado.jpg, '' Maja squinado'', a

Image:Hyas coarctatus.jpg, ''

Hyas coarctatus ''Hyas coarctatus'' is a marine crab species native to the North Atlantic. It is characterized by a lyriformed shell. Morphology ''Hyas coarctatus'' looks like the great spider crab (''H. araneus'') but has a lyriformed shell. The carapace of ...

'', an

References

Cenomanian first appearances Arthropod superfamilies Extant Cenomanian first appearances {{crab-stub