TheMajoidea are asuperfamily ofcrabs which includes the variousspider crabs.

Majoidea Temporal range:Cenomanian–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Macropodia rostrata (Inachidae)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Subsection:	Heterotremata
Superfamily:	Majoidea Samouelle, 1819

In "A classification of living and fossil genera of decapod crustaceans" De Grave and colleagues divided Majoidea into six families.^[1] 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 theWorld Register of Marine Species is as follows:^[2]

• EpialtidaeMacLeay, 1838
• InachidaeMacLeay, 1838
• InachoididaeDana, 1851
• MacrocheiridaeDana, 1851
• MajidaeSamouelle, 1819 – "true" spider crabs
• MithracidaeBalss, 1929
• OregoniidaeGarth, 1958
• †PriscinachidaeBreton, 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, the portly spider crab, a species of crab found in estuarine habitats on the east coast of North America.
• Hyas, a genus of spider crabs, including thegreat 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, found off Tasmania, are known to pile up on each other, the faster-moving crabs clambering over the smaller, slower ones.^[3]

There is one fossil family, Priscinachidae, represented by a single species,Priscinachus elongatus, from theCenomanian of France.^[4]

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  Hoplophrys oatesi, anEpialtidae
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  Limnopilos naiyanetri, aHymenosomatidae
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  Macrocheira kaempferi, anInachidae
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  Pyromaia cuspidata, anInachoididae
•  
  Maja squinado, aMajidae
•  
  Hyas coarctatus, anOregoniidae