The fiddler crab or calling crab may be any of more than one hundred species of semiterrestrial marine crabs in the family Ocypodidae, well known for their sexually dimorphic claws; the males' major claw is much larger than the minor claw, while the females' claws are both the same size. A smaller number of ghost crab and mangrove crab species are also found in the family Ocypodidae. This entire group is composed of small crabs, the largest being slightly over two inches (5 cm) across. Fiddler crabs are found along sea beaches and brackish intertidal mud flats, lagoons, swamps, and various other types of brackish or salt-water wetlands.
Xanthidae is a family of crabs known as gorilla crabs, mud crabs, pebble crabs or rubble crabs. Xanthid crabs are often brightly coloured and are highly poisonous, containing toxins which are not destroyed by cooking and for which no antidote is known. The toxins are similar to the tetrodotoxin and saxitoxin produced by puffer fish, and may be produced by bacteria in the genus Vibrio living in symbiosis with the crabs, mostly V. alginolyticus and V. parahaemolyticus.
Libinia is a genus of crabs in the family Epialtidae, containing twelve extant species:
Macrophthalmus is a genus of crabs which are widespread across the Indo-Pacific. It contains the following species : Species in this genus are often referred to as sentinel crabs.
Belliidae is a family of crabs of the order Decapoda.
Discoplax is a genus of terrestrial crabs. It is very closely related to the genus Cardisoma.
Menippidae is a family of crabs of the order Decapoda.
Goneplacidae is a family of crabs of the order Decapoda and the superfamily Goneplacoidea. It includes the following genera:
Herbstia is a genus of crabs, containing the following eleven species:
Dairoidea is a superfamily of crabs, comprising two families which each contain a single genus: Dairidae and Dacryopilumnidae (Dacryopilumnus) .
Etisus is a genus of crabs, containing the following extant species:
Macropodia is a genus of crabs, belonging to the family Inachidae. It contains the following species:
Epialtinae is a subfamily of crabs, containing the following genera:
Acanthonyx is a genus of crabs, in the family Epialtidae. Species so far known include:
Glyptoxanthus is a genus of crabs in the family Xanthidae, containing eight species. It was originally erected by Alphonse Milne-Edwards in 1879 for six species previously placed in the genus Actaea and elsewhere. Although previously included in subfamily Euxanthinae, the genus has a quite distinct morphology from other genera in that group, and was placed in 2011 in the new, monotypic subfamily, Glyptoxanthinae by Jose Christopher Mendoza and Danièle Guinot.
Micropanope is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following species:
Atergatis is a genus of crabs in the family Xanthidae, containing the following species:
Around 65 species of crab occur in the waters of the British Isles. All are marine, with the exception of the introduced Chinese mitten crab, Eriocheir sinensis, which occurs in fresh and brackish water. They range in size from the deep-water species Paromola cuvieri, which can reach a claw span of 1.2 metres, to the pea crab, which is only 4 mm (0.16 in) wide and lives inside mussel shells.
Inachoididae is a family of crabs originally erected by James Dwight Dana in 1852. It was not recognised as a valid family until the early 1980s. Its members closely resemble those of the family Inachidae, and the Inachoididae could be recognised as a subfamily of that family.
