| Majidae, European spider crab, Snow crab, Stenorhynchus seticornis, Mithracidae|
The Majoidea are a superfamily of crabs which includes the various spider crabs.
It comprises five or six families:Epialtidae
Hymenosomatidae – may not belong here
The families "Pisidae" and "Tychidae" are now treated as the subfamilies Pisinae and Tychinae of the family Epialtidae, and "Mithracidae" is now treated as the subfamily Mithracinae of the family Majidae.
Classification according to WoRMS :family Epialtidae MacLeay, 1838
family Hymenosomatidae MacLeay, 1838
family Inachidae MacLeay, 1838
family Inachoididae Dana, 1851
family Majidae Samouelle, 1819 – "true" spider crabs
family Mithracidae Balss, 1929
family Oregoniidae Garth, 1958
family Pisidae Dana, 1851
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 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, 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 of France.