Grapsidae is a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of crab

Crab

True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

s known variously as marsh crabs, shore crabs or talon crabs. It is not confirmed that the family forms a monophyletic group and some taxa

Taxon

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 may belong in other families. They are found along the shore among rocks, in estuaries

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

, marsh

Marsh

In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

es, and in some cases pelagic among drifting seaweed

Seaweed

Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

s and flotsam.

Genera

A number of taxa, formerly treated as subfamilies of the family Grapsidae are now considered families in their own right, including Varunidae

Varunidae

Varunidae is a family of thoracotrematan crabs. The delimitation of this family, part of the taxonomically confusing Grapsoidea, is undergoing revision. For a long time, they were placed at the rank of subfamily in the Grapsidae, but they appear to be closest to Macropthalmus and the Mictyridae,...

 and Plagusiidae

Plagusiidae

Plagusiidae is a family of crabs. It was formerly treated as a subfamily of the family Grapsidae, but has since been considered sufficiently distinct to be a family in its own right.Five genera are included in the family:*Davusia Guinot, 2007...

. Ten genera remain in the family, two of them known only from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s:

• Geograpsus
  Geograpsus
  Geograpsus is a genus of crabs in the family Grapsidae, containing five species:*Geograpsus crinipes *Geograpsus grayi *Geograpsus lividus *Geograpsus stormi De Man, 1895...
  
  Stimpson, 1858
• Goniopsis De Haan, 1833
• Grapsus
  Grapsus
  Grapsus is a genus of lightfoot crabs, comprising the following species:*Grapsus albolineatus Latreille in Milbert, 1812*Grapsus adscensionis *Grapsus fourmanoiri Crosnier, 1965*Grapsus grapsus...
  
  Lamarck, 1801
• Leptograpsodes Montgomery, 1931
• Leptograpsus H. Milne Edwards, 1853
• Litograpsus † Schweitzer & Karasawa, 2004
• Metopograpsus
  Metopograpsus
  Metopograpsus is a genus of crabs, containing the following extant species:*Metopograpsus frontalis Miers, 1880*Metopograpsus latifrons *Metopograpsus messor...
  
  H. Milne Edwards, 1853
• Miograpsus † Fleming, 1981
• Pachygrapsus
  Pachygrapsus
  Pachygrapsus is a genus of small shore crabs comprising the following species:*Pachygrapsus corrugatus *Pachygrapsus crassipes Randall, 1840*Pachygrapsus fakaravensis Rathbun, 1907...
  
  Randall, 1840
• Planes
  Planes (genus)
  The genus Planes currently comprises three extant species: Planes minutus , Planes marinus Rathbun, 1914, and Planes major . A further fossil species is known from the Middle Miocene of the Caucasus....
  
  Bowdich, 1825