![Mangrove crab Quepos](https://upload.wikimedia.org/wikipedia/commons/8/80/Mangrove_crab_Quepos.JPG)
Mangrove crabs are
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s that live among
mangrove
A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...
s, and may belong to many different
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
and even
families
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...
. They have been shown to be
ecologically
Ecology () is the study of the relationships between living organisms, including humans, and their biophysical environment, physical environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosy ...
significant in many ways. They keep much of the energy within the
forest
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
by burying and consuming
leaf litter
Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...
.
Along with burrowing in the ground,
at high tide and in the face of predators these crustaceans can climb trees to protect themselves.
The hermit crab and the mangrove crab are the only crustaceans that can climb trees as a defense mechanism.
Furthermore, their
feces
Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...
may form the basis of a
coprophagous
Coprophagia () or coprophagy () is the consumption of feces. The word is derived from the grc, κόπρος , "feces" and , "to eat". Coprophagy refers to many kinds of feces-eating, including eating feces of other species (heterospecifics), of ...
food chain contributing to mangrove secondary production.
Mangrove
crab larvae are the major source of food for
juvenile fish
Fish go through various life stages between fertilization and adulthood. The life of a fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac which ...
inhabiting the adjacent waterways, indicating that crabs also help nearshore
fisheries
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...
. The adult crabs are food for threatened species such as the
crab plover
The crab-plover or crab plover (''Dromas ardeola)'' is a bird related to the waders, but sufficiently distinctive to merit its own family Dromadidae. Its relationship within the Charadriiformes is unclear, some have considered it to be closely ...
.
Their burrows alter the
topography
Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps.
Topography is a field of geoscience and planetary sci ...
and sediment grain size of the mangrove, and help aerate the sediment. Removing crabs from an area causes significant increases in
sulfide
Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...
s and
ammonium
The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...
concentrations, which in turn affects the productivity and reproductive output of the vegetation, supporting the hypothesis that mangrove crabs are a
keystone species
A keystone species is a species which has a disproportionately large effect on its natural environment relative to its abundance, a concept introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaini ...
.
Species of mangrove crabs
* ''
Aratus pisonii'', Americas
* ''
Haberma
''Haberma'' is genus of small mangrove or terrestrial crabs, typically less than across the carapace.
The genus was established by Ng and Schubart in 2002 with the discovery of the species ''Haberma nanum'' in Singapore. A second species, ''H ...
'', genus of small mangrove crabs,
Indo-Pacific
The Indo-Pacific is a vast biogeographic region of Earth.
In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...
, including:
** ''
Haberma tingkok'', Hong Kong
* ''
Metopograpsus messor
''Metopograpsus messor'' is a species of grapsid crab that lives in mangroves from East Africa to Fiji.
Description
It grows up to wide. The carapace and legs are mottled brownish green, while the claws are brownish red.
Distribution
The ...
'',
Indo-Pacific
The Indo-Pacific is a vast biogeographic region of Earth.
In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...
* ''
Metopograpsus thukuhar
The thukuhar shore-crab (''Metopograpsus thukuhar''), also known as alamihi crab, is a species of crab that lives in mangroves all over from Africa to Fiji.
Distribution
A mangrove inhabitant, it is found all over mangrove forests of Hawaii, Ma ...
'', Indo-Pacific
* ''
Neosarmatium meinerti'', Indo-Pacific
* ''
Neosarmatium smithi'', Indo-Pacific
* ''
Parasesarma leptosoma'', western Indian Ocean
* ''
Perisesarma'', genus with 23 species, primarily Indo-Pacific, with two West African species, including:
** ''
Perisesarma bidens'', Indo-Pacific
** ''
Perisesarma guttatum'', western Indian Ocean
* ''
Scylla serrata
''Scylla serrata'' (often called mud crab or mangrove crab, although both terms are highly ambiguous, and black crab) is an ecologically important species of crab found in the estuaries and mangroves of Africa, Australasia, and Asia. In their ...
'', Indo-Pacific
* ''
Scylla tranquebarica
''Scylla tranquebarica'' is a species of mangrove crab in the genus ''Scylla''. ''Scylla tranquebarica'', one of several crabs known as the mud crab, is found in mangrove areas from Pakistan and Taiwan to the Malay Archipelago and other Indo-Paci ...
'', Indo-Pacific
* ''
Sesarma
''Sesarma'' is a genus of terrestrial crabs endemic to the Americas.
Many species within this genus live in mangroves. They have evolved to be fully terrestrial, which means they do not have to return to the sea even to spawn. Several species i ...
'', genus with close to 20 species, many of which live in mangroves, Americas, Indo-Pacific
* ''
Ucides cordatus
''Ucides cordatus'', the swamp ghost crab (or ''caranguejo-uçá'' in Portuguese), is one of two species of crabs in the genus ''Ucides''. This species of crab is native to many coasts off of the western Atlantic Ocean. It has been found to be na ...
'', western Atlantic Ocean
See also
*
Fiddler crab
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 sexual dimorphism, sexually dimorphic claws; the males' major claw is much larger than th ...
*
Grapsidae
The Grapsidae are a 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 taxa may belong in other families. They are found along the shore among rocks ...
*
Mangrove ecoregions
A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in several ...
References
{{Reflist, 2
External links
East African mangrove crabsMangrove crab ''Ucides cordatus'' (Brazil)Complete larval and early juvenile development of the mangrove crab ''Perisesarma fasciatum'' (Singapore)Laboratory cultured zoeae and megalopa of the mangrove crab ''Metaplax distincta''Regulation of pulmonary blood flow and of blood pressure in a mangrove crab (''Goniopsis cruentata'')''Haberma nanum'', a new genus and new species of mangrove crab from Singapore
Crabs
Mangrove fauna
Arthropod common names
ja:ノコギリガザミ