The Grapsoidea are a superfamily of

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s; they are well known and contain many

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

which are terrestrial (land-living), semiterrestrial (taking to the sea only for reproduction), or limnic (living in

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include ...

). Another well-known member with a more conventional lifestyle is the Chinese mitten crab, ''Eriocheir sinensis''. The delimitation of the

Grapsidae The Grapsidae are a family (biology), family of crabs known variously as marsh crabs, shore crabs, or talon crabs. The family has not been confirmed to form a monophyletic group and some Taxon, taxa may belong in other families. They are found al ...

and Plagusiidae is in need of revision; the latter at least is not

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. The same apparently holds true for several

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

in the Sesarmidae. The closest living relatives of the Grapsoidea are the

Ocypodoidea The Ocypodoidea, or ocypoid crabs, are a superfamily of crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthro ...

. In fact, they seem to be

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

with respect to each other and it seems warranted to merge the Ocypodoidea into the Grapsoidea.

References

Crabs Arthropod superfamilies {{Grapsoidea-stub