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{{Short description|Species of crab}}
'''''Armases cinereum''''', also known as the '''Squareback Marsh Crab''' or '''Wharf Crab''', Is a member of the [[genus]] '''''Armases''''' and is a [[species]] of [[crab]] in the family [[Sesarmidae]].<ref name=":0">{{Cite web |title=ITIS - Report: Armases cinereum |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=621739#null%20%202)%20(Habitat%20specifics)%20https://link.springer.com/chapter/ |access-date=2022-04-09 |website=www.itis.gov}}</ref> The Wharf Crab is a small crab and is dark brown to muddy in color, which allows it to blend in well with its usual surroundings. It is found on the Atlantic southeastern coast, down into the Gulf of Mexico.<ref name=":1">{{Cite journal |last=Abele |first=Lawrence G. |date=1992 |title=A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus |url=http://dx.doi.org/10.5479/si.00810282.527 |journal=Smithsonian Contributions to Zoology |issue=527 |pages=1–60 |doi=10.5479/si.00810282.527 |issn=0081-0282}}</ref> It is an omnivore and is prevalent in marshy coastal environments along the Southwestern Atlantic .<ref>{{Cite journal |last=Buck |first=Tracy L. |last2=Breed |first2=Greg A. |last3=Pennings |first3=Steven C. |last4=Chase |first4=Margo E. |last5=Zimmer |first5=Martin |last6=Carefoot |first6=Thomas H. |date=2003-07-29 |title=Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat complexity |url=https://www.sciencedirect.com/science/article/pii/S0022098103001461 |journal=Journal of Experimental Marine Biology and Ecology |language=en |volume=292 |issue=1 |pages=103–116 |doi=10.1016/S0022-0981(03)00146-1 |issn=0022-0981}}</ref>
{{Speciesbox

| image = Armases cinereum P1010755a.jpg
== Taxonomy ==
| genus = Armases
''Armases'' is a genus which is a part of the family Sesarmidae and the subfamily Sesarminae of [[Grapsidae]].<ref name=":12">{{Cite journal |last=Abele |first=Lawrence G. |date=1992 |title=A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus |url=http://dx.doi.org/10.5479/si.00810282.527 |journal=Smithsonian Contributions to Zoology |issue=527 |pages=1–60 |doi=10.5479/si.00810282.527 |issn=0081-0282}}</ref> There are around 10 described [[Genus|genera]] within the subfamily Sesarminae. <ref name=":12" /> ''Armases'' can be distinguished from members of other genera such as ''[[Sesarma]]'' or ''Sarmatium'' by the way its carpace has laterally parallel margins on each side of its body.<ref name=":12" /> This gives ''Armases cinereum'' its characteristic square shape and is the namesake for Squareback Marsh Crab. ''Armases cinereum'' is one of 11 described species in the genus ''Armases.''<ref name=":02">{{Cite web |title=ITIS - Report: Armases cinereum |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=621739#null%20%202)%20(Habitat%20specifics)%20https://link.springer.com/chapter/ |access-date=2022-04-09 |website=www.itis.gov}}</ref> <ref name=":12" /> The species ''cinereum'' was originally described by Louis Bosc in 1802, and was classified under the genus ''Sesarma.''<ref>{{Cite book |last=Bosc |first=Louis Augustin Guillaume |url=https://books.google.com/books?hl=en&lr=&id=zugrAQAAMAAJ&oi=fnd&pg=PA1&ots=cE3TBDulfE&sig=AFpI284Ov6JxeOPpAsFe-uLBfgk |title=Histoire naturelle des crustacés, contenant leur description et leurs moeurs: avec figures dessinées d'après nature |date=1828 |publisher=Roret, Libraire, Rue Hautefeuille |language=fr}}</ref> However, in 1992, the species was reclassified under the genus ''Armases'' by Lawrence Able.<ref name=":12" />
| species = cinereum
{{Taxobox
| authority = (Bosc, 1802)
| image = Wharf Crab on rock close up.jpg
| image_caption = Wharf Crab
| regnum = Animalia
| phylum = Athropoda
| classis = Malacostraca
| ordo = Decapoda
| familia = Sesarmidae
| genus = Armases
| species = A. cinereum
| binomial = Armases cinereum
}}
}}
[[File:Wharf_Crab_on_rock.jpg|thumb|Wharf crab blending into a rocky environment.]]


'''''Armases cinereum''''', also known as the '''squareback marsh crab''' or '''wharf crab''', is a [[species]] of crab in the family [[Sesarmidae]].<ref name=":02">{{Cite web |title=ITIS - Report: Armases cinereum |url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=621739#null%20%202)%20(Habitat%20specifics)%20https://link.springer.com/chapter/ |access-date=2022-04-09 |website=www.itis.gov}}</ref> The wharf crab is a small crab that is dark brown to muddy in color, which allows it to blend in with its usual surroundings. It is found on the Atlantic southeastern coast, down into the Gulf of Mexico.<ref name=":14">{{Cite journal |last=Abele |first=Lawrence G. |date=1992 |title=A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus |journal=Smithsonian Contributions to Zoology |issue=527 |pages=1–60 |doi=10.5479/si.00810282.527 |doi-access=free |issn=0081-0282}}</ref> It is an omnivore and is prevalent in marshy coastal environments along the Southwestern Atlantic.<ref>{{Cite journal |last1=Buck |first1=Tracy L. |last2=Breed |first2=Greg A. |last3=Pennings |first3=Steven C. |last4=Chase |first4=Margo E. |last5=Zimmer |first5=Martin |last6=Carefoot |first6=Thomas H. |date=2003-07-29 |title=Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat complexity |journal=Journal of Experimental Marine Biology and Ecology |language=en |volume=292 |issue=1 |pages=103–116 |doi=10.1016/S0022-0981(03)00146-1 |issn=0022-0981}}</ref>
=== Species of the genus ''Armases'' ===
'''Armases ricordi'''<ref name=":12" />


== Description ==
'''Armases americanum'''<ref name=":12" />
The genus ''Armases'' is defined by a primarily equatorial smooth [[carapace]], which can be either slightly wider than long or vice versa.<ref name=":14"/> A distinct row of hair is present on the lower margin and second walking legs do not have any pubescence.<ref name=":14"/> ''Armases'' can be distinguished from members of other genera such as ''[[Sesarma]]'' or ''Sarmatium'' by the way its carapace has laterally parallel margins on each side of its body.<ref name=":14"/> This gives ''Armases cinereum'' its characteristic square shape and is the namesake for squareback marsh crab.


''Armases cinereum'', like most [[Decapoda|decapod]] crabs is vertically compressed with the majority of its body being composed of the carapace; the eyes are located at the top of eye stalks, the abdomen and thorax are positioned under the carapace, and there are four legs on each side of the carapace with one claw per side positioned anterior of the legs.<ref>{{Cite journal |last1=Abbas |first1=Eman M. |last2=Abdelsalam |first2=Khaled M. |last3=Mohammed-Geba |first3=Khaled |last4=Ahmed |first4=Hamdy O. |last5=Kato |first5=Mikio |date=2016-09-01 |title=Genetic and morphological identification of some crabs from the Gulf of Suez, Northern Red Sea, Egypt |journal=The Egyptian Journal of Aquatic Research |language=en |volume=42 |issue=3 |pages=319–329 |doi=10.1016/j.ejar.2016.08.003 |issn=1687-4285 |doi-access=free}}</ref>''Armases'' is a useful species for studying trophic dynamics in coastal habitats due to their high local abundance in both saltmarsh and mangrove habitats (with a distribution ranging in elevation from subtidal to supratidal), and wide-ranging mobility that spans the mangrove/upland ecotone<ref>{{Cite thesis |last=Kiskaddon |first=Erin Paige |date=2016 |title=Feeding Patterns and Trophic Food Web Dynamics of ''Armases cinereum'' Across a Mangrove/Upland Ecotone |url=http://scholarcommons.usf.edu/etd/6525 |website=USF Tampa Graduate Theses and Dissertations |type=M.S.}}</ref>
'''Armases roberti'''<ref name=":12" />


=== Sexual dimorphism ===
'''Armases angustipes'''<ref name=":12" />
[[Sexual dimorphism]] is evident in the species, as males are typically slightly larger and have a more prominent palm.<ref name=":14"/> Its size ranges from 10.0 to 18.0&nbsp;mm in length for mature males and 11.0 to 17.2&nbsp;mm for mature females.<ref name=":14"/> Males have a subtriangular outline on their abdomen with a [[telson]] that is equal in width and length, while females have a subcircular outline on their abdomen with the telson being larger in width than length.<ref name=":14"/>
[[File:Laguncularia racemosa in the Everglades.jpg|thumb|Mangrove Habitat]]
[[File:Salt marsh, Newry - geograph.org.uk - 3139235.jpg|thumb|Salt Marsh Habitat]]


== Habitat and distribution ==
'''Armases miersii'''<ref name=":12" />
The wharf crab has a wide distribution in temperate to tropical coastal environments. The species has an abundantly high density in the coastal areas where it is found.<ref name=":22">{{Cite journal |last1=Kiskaddon |first1=Erin |last2=Chernicky |first2=Kiley |last3=Bell |first3=Susan |date=2019-02-15 |title=Resource use by and trophic variability of Armases cinereum (Crustacea, Brachyura) across human-impacted mangrove transition zones |journal=PLOS ONE |language=en |volume=14 |issue=2 |pages=e0212448 |doi=10.1371/journal.pone.0212448 |issn=1932-6203 |pmc=6377144 |pmid=30768634|bibcode=2019PLoSO..1412448K |doi-access=free }}</ref> Specimens can be found from the Chesapeake Bay area down and around coastal Florida, and west along the coast all the way to Veracruz, Mexico.<ref>{{Cite journal |last=Williams |first=Austin B. |date=1984 |title=Shrimps, Lobsters, and crabs of the Atlantic Coast of the Eastern United States, Maine to Florida |journal=Estuaries |volume=8 |issue=1 |pages=77 |doi=10.2307/1352125 |jstor=1352125 |s2cid=83630574 |issn=0160-8347}}</ref><ref name=":14"/> The species is usually found in intertidal zones and can be found up to 50 m inland; they can thrive in a variety of habitats as well.<ref name=":14" /> These habitats commonly include ''[[Spartina]]'' (marsh grass) marshes and ''[[Rhizophora]]'' (mangrove) swamps.<ref name=":14" /> Within these habitats they prefer to live among and under rocks and debris brought in with the tides. Due to the high population density in coastal environments wharf crabs can be used as indicators of habitat conditions.<ref name=":22"/>


== Diet & ecology ==
'''Armases angustum'''<ref name=":12" />
While the wharf crab is often deemed a [[detritivore]], it is highly [[omnivorous]] and will supplement a detritus diet with microscopic insects and invertebrates.<ref>{{Cite journal |last1=Zimmer |first1=Martin |last2=Pennings |first2=Steven C. |last3=Buck |first3=Tracy L. |last4=Carefoot |first4=Thomas H. |date=2004-10-01 |title=Salt marsh litter and detritivores: A closer look at redundancy |journal=Estuaries |language=en |volume=27 |issue=5 |pages=753–769 |doi=10.1007/BF02912038 |s2cid=10318266 |issn=0160-8347}}</ref> In mangrove habitats wharf crabs are a key component as omnivores in the food chain, they serve as [[carnivore]]s, [[herbivore]]s, and detritivores.<ref name=":22"/> Some examples of what the wharf crab would eat in a Mangrove habitat include, insects, partially decomposed ''[[Avicennia]]'' (Black Mangrove), and leaves from Mangroves or other maritime vegetation.<ref name=":22" /> When feeding on plant matter wharf crabs will prioritize softer plants over plants with a tougher exterior.<ref>{{Cite journal |last1=Pennings |first1=Steven C. |last2=Carefoot |first2=Thomas H. |last3=Siska |first3=Erin L. |last4=Chase |first4=Margo E. |last5=Page |first5=Teresa A. |title=Feeding Preferences of a Generalist Salt-Marsh crab: Relative Importance of Multiple Plant Traits |date=September 1998 |journal=Ecology |language=en |volume=79 |issue=6 |pages=1968–1979 |doi=10.1890/0012-9658(1998)079[1968:FPOAGS]2.0.CO;2 |issn=0012-9658}}</ref> When both plant and animal food sources are readily available the wharf crab will choose the animal prey.<ref name=":22" /> The diet of ''Armases cinereum'' coincides directly with the environment in which it is found and what the prominent food availability is in that environment. Consequently, this diverse diet also allows the species to live at relatively high population densities across a large margin of coastal ecosystems.<ref name=":22" />


== Taxonomy ==
'''Armases occidentale'''<ref name=":12" />
''Armases'' is a genus which is a part of the family Sesarmidae and the subfamily Sesarminae of [[Grapsidae]].<ref name=":14"/> There are around 10 described genera within the subfamily Sesarminae.<ref name=":14"/> ''Armases cinereum'' is one of 11 described species in the genus ''Armases.''<ref name=":02"/><ref name=":14"/> The species ''cinereum'' was originally described by Louis Bosc in 1802, and was classified under the genus ''Sesarma.''<ref>{{Cite book |last=Bosc |first=Louis Augustin Guillaume |url=https://books.google.com/books?id=zugrAQAAMAAJ&pg=PA1 |title=Histoire naturelle des crustacés, contenant leur description et leurs moeurs: avec figures dessinées d'après nature |date=1828 |publisher=Roret, Libraire, Rue Hautefeuille |language=fr}}</ref> However, in 1992, the species was reclassified under the genus ''Armases'' by Lawrence Able.<ref name=":14"/>


== Reproduction and life stages ==
'''Armases gorei'''<ref name=":12" />


Crab reproduction occurs through a process known as [[Spawn (biology)|spawning]] where eggs are released onto the abdomen of the female crab via the oviduct.<ref name=":3">{{Cite book |last=WEIS |first=JUDITH S. |title=Walking Sideways: The Remarkable World of crabs |date=2012 |publisher=Cornell University Press |isbn=978-0-8014-5050-1 |edition=1st |jstor=10.7591/j.cttn34xc}}</ref> The spawning season for ''Armases cinereum'' is typically between March and July.<ref>{{Cite journal |last1=Hasek |first1=B. E. |last2=Felder |first2=D. L. |date=March 2005 |title=Biochemical composition of ovary, embryo, and hepatopancreas in the grapsoid crabs Armases cinereum and Sesarma nr. reticulatum (Crustacea, Decapoda) |journal=Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology |language=en |volume=140 |issue=3 |pages=455–463 |doi=10.1016/j.cbpc.2004.11.010 |pmid=15694594 |issn=1096-4959}}</ref> The species in the genus ''Armases'' are known as ovigerous, meaning they carry their eggs while they undergo embryonic development.<ref name=":3" /><ref>{{Cite journal |last1=Cuesta |first1=José A. |last2=Anger |first2=Klaus |date=2001 |title=Larval Morphology of the Sesarmid crab Armases angustipes Dana, 1852 (Decapoda, Brachyura, Grapsoidea) |journal=Journal of Crustacean Biology |volume=21 |issue=3 |pages=821–838 |doi=10.1163/20021975-99990175 |jstor=1549582 |issn=0278-0372 |doi-access=free}}</ref> ''Armases cinereum'' produce between 2,000 and 12,000 eggs in a brood.<ref name=":4">{{Cite journal |last1=Figueiredo |first1=Joana |last2=Penha-Lopes |first2=Gil |last3=Anto |first3=Justin |last4=Narciso |first4=Luís |last5=Lin |first5=Junda |date=April 2008 |title=Fecundity, brood loss and egg development through embryogenesis of Armases cinereum (Decapoda: Grapsidae) |journal=Marine Biology |language=en |volume=154 |issue=2 |pages=287–294 |doi=10.1007/s00227-008-0922-2 |s2cid=55307816 |issn=1432-1793}}</ref> This number is dependent on [[fecundity]] which is proportional to the size of the female producing the eggs.<ref name=":3" /> Additionally fecundity represents the energy investment an individual must make to produce a brood of eggs.<ref name=":4" /> Eggs are energetically expensive to produce and being ovigerous in nature adds to the energy expenditure. When these eggs hatch larva called [[Crustacean larva|zoea]] emerge.<ref name=":3" /> Zoea are planktonic crab larvae with their trait characteristic being a large spine positioned dorsally.<ref name=":3" /> Crab zoea will grow and [[Moulting|molt]] several times before they move into their next life stage called the megalopa stage.<ref name=":3" /> In this stage the eyes become positioned on eyestalks, a carapace is formed, and the abdomen becomes positioned outward from the carapace posteriorly.<ref name=":3" /> The next time the crab molts it will become a juvenile version of its adult form and its larval life stages will be complete.<ref name=":3" />
'''Armases magdalenense'''<ref name=":12" />


== References ==
'''Armases benedicti'''<ref name=":12" />
{{Reflist}}


{{Taxonbar|from=Q6497777}}
== Morphology ==
The genus ''Armases'' is defined by a primarily equatorial smooth [[Carapace|carpace]], which can be either slightly wider than long or vice versa.<ref name=":13">{{Cite journal |last=Abele |first=Lawrence G. |date=1992 |title=A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus |url=http://dx.doi.org/10.5479/si.00810282.527 |journal=Smithsonian Contributions to Zoology |issue=527 |pages=1–60 |doi=10.5479/si.00810282.527 |issn=0081-0282}}</ref> A distinct row of hair is present on the lower margin and second walking legs do not have any pubescence.<ref name=":13" />


[[Category:Sesarmidae]]
''Armases cinereum'', like most [[Decapoda|decapod]] crabs is vertically compressed with the majority of its body being composed of the carpace; the eyes are located at the top of eye stalks, the abdomen and thorax are positioned under the carpace, and there are four legs on each side of the carpace with one claw per side positioned anterior of the legs.<ref>{{Cite journal |last=Abbas |first=Eman M. |last2=Abdelsalam |first2=Khaled M. |last3=Mohammed-Geba |first3=Khaled |last4=Ahmed |first4=Hamdy O. |last5=Kato |first5=Mikio |date=2016-09-01 |title=Genetic and morphological identification of some crabs from the Gulf of Suez, Northern Red Sea, Egypt |url=https://www.sciencedirect.com/science/article/pii/S1687428516300516 |journal=The Egyptian Journal of Aquatic Research |language=en |volume=42 |issue=3 |pages=319–329 |doi=10.1016/j.ejar.2016.08.003 |issn=1687-4285}}</ref>

=== Sexual dimorphism ===
[[Sexual dimorphism]] is evident in the species, as males are typically slightly larger and have a more prominent palm.<ref name=":13" /> Its size ranges from 10.0 to 18.0 mm in length for mature males and 11.0 to 17.2 mm for mature females.<ref name=":13" /> Males have a subtriangular outline on thair abdomen with a [[telson]] that is equal in width and length, while females have a subcircular outline on their abdomen with the telson being larger in width than length.<ref name=":13" />

== Habitat and Distribution ==
The Wharf Crab has a wide distribution in temperate to tropical coastal environments. Ther species has an abundantly high density in the coastal areas where it is found.<ref name=":2">{{Cite journal |last=Kiskaddon |first=Erin |last2=Chernicky |first2=Kiley |last3=Bell |first3=Susan |date=2019-02-15 |title=Resource use by and trophic variability of Armases cinereum (Crustacea, Brachyura) across human-impacted mangrove transition zones |url=https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212448 |journal=PLOS ONE |language=en |volume=14 |issue=2 |pages=e0212448 |doi=10.1371/journal.pone.0212448 |issn=1932-6203 |pmc=PMC6377144 |pmid=30768634}}</ref> Specimens can be found from the Chesapeake Bay area down and around coastal Flordia, and west along the coast all the way to Veracruz, Mexico.<ref>{{Cite journal |last=Williams |first=Austin B. |date=1984 |title=Shrimps, Lobsters, and Crabs of the Atlantic Coast of the Eastern United States, Maine to Florida |url=http://dx.doi.org/10.2307/1352125 |journal=Estuaries |volume=8 |issue=1 |pages=77 |doi=10.2307/1352125 |issn=0160-8347}}</ref><ref name=":14">{{Cite journal |last=Abele |first=Lawrence G. |date=1992 |title=A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus |url=http://dx.doi.org/10.5479/si.00810282.527 |journal=Smithsonian Contributions to Zoology |issue=527 |pages=1–60 |doi=10.5479/si.00810282.527 |issn=0081-0282}}</ref> The species is usually found in intertidal zones and can be found up to 50 m inland; they can thrive in a variety of habitats as well.<ref name=":14" /> These habitats commonly include ''[[Spartina]]'' (marsh grass) marshes and ''[[Rhizophora]]'' (mangrove) swamps.<ref name=":14" /> Within these habitats they prefer to live among and under rocks and debris brought in with the tides. Due to the high population density in coastal environments Wharf Crabs can be used as indicators of habitat conditions.<ref name=":2" />

== Diet ==
While the Wharf Crab is often deemed a [[detritivore]], it is highly omnivoros and will supplement a detritus diet with microscopic insects and invertebrates.<ref>{{Cite journal |last=Zimmer |first=Martin |last2=Pennings |first2=Steven C. |last3=Buck |first3=Tracy L. |last4=Carefoot |first4=Thomas H. |date=2004-10-01 |title=Salt marsh litter and detritivores: A closer look at redundancy |url=https://doi.org/10.1007/BF02912038 |journal=Estuaries |language=en |volume=27 |issue=5 |pages=753–769 |doi=10.1007/BF02912038 |issn=0160-8347}}</ref> In Mangrove habitats Wharf Crabs are a key componet as [[Omnivore|omnivores]] in the food chain, they serve as [[Carnivore|carnivores]], [[Herbivore|herbivores]], and detritivores.<ref name=":22">{{Cite journal |last=Kiskaddon |first=Erin |last2=Chernicky |first2=Kiley |last3=Bell |first3=Susan |date=2019-02-15 |title=Resource use by and trophic variability of Armases cinereum (Crustacea, Brachyura) across human-impacted mangrove transition zones |url=https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212448 |journal=PLOS ONE |language=en |volume=14 |issue=2 |pages=e0212448 |doi=10.1371/journal.pone.0212448 |issn=1932-6203 |pmc=PMC6377144 |pmid=30768634}}</ref>Some examples of what the Wharf Crab would eat in a Mangrove habitat include, insects, partially decomposed ''[[Avicennia]]'' (Black Mangrove), and leaves from Mangroves or other maritime vegetation.<ref name=":22" /> When feeding on plant matter Wharf Crabs will prioritze softer plants over plants with a tougher exterior.<ref>{{Cite journal |last=Pennings |first=Steven C. |last2=Carefoot |first2=Thomas H. |last3=Siska |first3=Erin L. |last4=Chase |first4=Margo E. |last5=Page |first5=Teresa A. |date=1998 |title=FEEDING PREFERENCES OF A GENERALIST SALT-MARSH CRAB: RELATIVE IMPORTANCE OF MULTIPLE PLANT TRAITS |url=http://doi.wiley.com/10.1890/0012-9658(1998)079[1968:FPOAGS]2.0.CO;2 |journal=Ecology |language=en |volume=79 |issue=6 |pages=1968–1979 |doi=10.1890/0012-9658(1998)079[1968:FPOAGS]2.0.CO;2 |issn=0012-9658}}</ref> When both plant and animal food sources are readily avaliable the Wharf Crab will choose the animal prey.<ref name=":22" /> The diet of ''Armases cinereum'' coincides directly with the environment in which it is found and what the prominent food avaliablilty is in that environment. Consequently this diverse diet also allows the species to live at relatively high population densities across a large margin of coastal ecosystems.<ref name=":22" />

== Reproduction and Life Stages ==
Crab reproduction occurs through a process known as [[Spawn (biology)|spawning]] where eggs are released onto the abdomen of the famle crab via the oviduct.<ref name=":3">{{Cite book |last=WEIS |first=JUDITH S. |url=https://www.jstor.org/stable/10.7591/j.cttn34xc |title=Walking Sideways: The Remarkable World of Crabs |date=2012 |publisher=Cornell University Press |isbn=978-0-8014-5050-1 |edition=1 |doi=10.7591/j.cttn34xc.9}}</ref> The spawning season for ''Armases cinereum'' is typically between March and July.<ref>{{Cite journal |last=Hasek |first=B. E. |last2=Felder |first2=D. L. |date=2005-03-01 |title=Biochemical composition of ovary, embryo, and hepatopancreas in the grapsoid crabs Armases cinereum and Sesarma nr. reticulatum (Crustacea, Decapoda) |url=https://www.sciencedirect.com/science/article/pii/S1096495904003768 |journal=Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology |language=en |volume=140 |issue=3 |pages=455–463 |doi=10.1016/j.cbpc.2004.11.010 |issn=1096-4959}}</ref> The species in the genus ''Armases'' are known as ovigerous, meaning they carry their eggs while they undergo embryonic development.<ref name=":3" /><ref>{{Cite journal |last=Cuesta |first=José A. |last2=Anger |first2=Klaus |date=2001 |title=Larval Morphology of the Sesarmid Crab Armases angustipes Dana, 1852 (Decapoda, Brachyura, Grapsoidea) |url=https://www.jstor.org/stable/1549582 |journal=Journal of Crustacean Biology |volume=21 |issue=3 |pages=821–838 |issn=0278-0372}}</ref> ''Armases cinereum'' produce between 2,000-12,000 eggs in a brood.<ref name=":4">{{Cite journal |last=Figueiredo |first=Joana |last2=Penha-Lopes |first2=Gil |last3=Anto |first3=Justin |last4=Narciso |first4=Luís |last5=Lin |first5=Junda |date=2008-04-01 |title=Fecundity, brood loss and egg development through embryogenesis of Armases cinereum (Decapoda: Grapsidae) |url=https://doi.org/10.1007/s00227-008-0922-2 |journal=Marine Biology |language=en |volume=154 |issue=2 |pages=287–294 |doi=10.1007/s00227-008-0922-2 |issn=1432-1793}}</ref> This number is dependent on [[fecundity]] which is proportional to the size of the female producing the eggs.<ref name=":3" /> Additionally fecundity represents the energy investment an individual must make to produce a brood of eggs.<ref name=":4" /> Eggs are energetically expensive to produce and being ovigerous in nature adds to the energy expendature. When these eggs hatch larva called [[Crustacean larva|zoea]] emerge.<ref name=":3" /> Zoea are planktonic crab larvae with their trait characteristic being a large spine positioned dorsally.<ref name=":3" /> Crab zoea will grow and [[Moulting|molt]] several times before they move into their next life stage called the megalopa stage.<ref name=":3" /> In this stage the eyes become positioned on eyestalks, a carpace is formed, and the abdomen becomes positioned outward from the carpace posteriorly.<ref name=":3" /> The next time the crab molts it will become a juvenile version of its adult form and its larval life stages will be complete.<ref name=":3" />

== References ==
{{Short description|Species of crab}}
[[Category:decapods]]
[[Category:Articles created by Qbugbot]]
[[Category:Articles created by Qbugbot]]
[[Category:Crustaceans described in 1802]]
[[Category:Crustaceans described in 1802]]

Latest revision as of 13:21, 13 October 2024

Armases cinereum
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Sesarmidae
Genus: Armases
Species:
A. cinereum
Binomial name
Armases cinereum
(Bosc, 1802)

Armases cinereum, also known as the squareback marsh crab or wharf crab, is a species of crab in the family Sesarmidae.[1] The wharf crab is a small crab that is dark brown to muddy in color, which allows it to blend in with its usual surroundings. It is found on the Atlantic southeastern coast, down into the Gulf of Mexico.[2] It is an omnivore and is prevalent in marshy coastal environments along the Southwestern Atlantic.[3]

Description

[edit]

The genus Armases is defined by a primarily equatorial smooth carapace, which can be either slightly wider than long or vice versa.[2] A distinct row of hair is present on the lower margin and second walking legs do not have any pubescence.[2] Armases can be distinguished from members of other genera such as Sesarma or Sarmatium by the way its carapace has laterally parallel margins on each side of its body.[2] This gives Armases cinereum its characteristic square shape and is the namesake for squareback marsh crab.

Armases cinereum, like most decapod crabs is vertically compressed with the majority of its body being composed of the carapace; the eyes are located at the top of eye stalks, the abdomen and thorax are positioned under the carapace, and there are four legs on each side of the carapace with one claw per side positioned anterior of the legs.[4]Armases is a useful species for studying trophic dynamics in coastal habitats due to their high local abundance in both saltmarsh and mangrove habitats (with a distribution ranging in elevation from subtidal to supratidal), and wide-ranging mobility that spans the mangrove/upland ecotone[5]

Sexual dimorphism

[edit]

Sexual dimorphism is evident in the species, as males are typically slightly larger and have a more prominent palm.[2] Its size ranges from 10.0 to 18.0 mm in length for mature males and 11.0 to 17.2 mm for mature females.[2] Males have a subtriangular outline on their abdomen with a telson that is equal in width and length, while females have a subcircular outline on their abdomen with the telson being larger in width than length.[2]

Mangrove Habitat
Salt Marsh Habitat

Habitat and distribution

[edit]

The wharf crab has a wide distribution in temperate to tropical coastal environments. The species has an abundantly high density in the coastal areas where it is found.[6] Specimens can be found from the Chesapeake Bay area down and around coastal Florida, and west along the coast all the way to Veracruz, Mexico.[7][2] The species is usually found in intertidal zones and can be found up to 50 m inland; they can thrive in a variety of habitats as well.[2] These habitats commonly include Spartina (marsh grass) marshes and Rhizophora (mangrove) swamps.[2] Within these habitats they prefer to live among and under rocks and debris brought in with the tides. Due to the high population density in coastal environments wharf crabs can be used as indicators of habitat conditions.[6]

Diet & ecology

[edit]

While the wharf crab is often deemed a detritivore, it is highly omnivorous and will supplement a detritus diet with microscopic insects and invertebrates.[8] In mangrove habitats wharf crabs are a key component as omnivores in the food chain, they serve as carnivores, herbivores, and detritivores.[6] Some examples of what the wharf crab would eat in a Mangrove habitat include, insects, partially decomposed Avicennia (Black Mangrove), and leaves from Mangroves or other maritime vegetation.[6] When feeding on plant matter wharf crabs will prioritize softer plants over plants with a tougher exterior.[9] When both plant and animal food sources are readily available the wharf crab will choose the animal prey.[6] The diet of Armases cinereum coincides directly with the environment in which it is found and what the prominent food availability is in that environment. Consequently, this diverse diet also allows the species to live at relatively high population densities across a large margin of coastal ecosystems.[6]

Taxonomy

[edit]

Armases is a genus which is a part of the family Sesarmidae and the subfamily Sesarminae of Grapsidae.[2] There are around 10 described genera within the subfamily Sesarminae.[2] Armases cinereum is one of 11 described species in the genus Armases.[1][2] The species cinereum was originally described by Louis Bosc in 1802, and was classified under the genus Sesarma.[10] However, in 1992, the species was reclassified under the genus Armases by Lawrence Able.[2]

Reproduction and life stages

[edit]

Crab reproduction occurs through a process known as spawning where eggs are released onto the abdomen of the female crab via the oviduct.[11] The spawning season for Armases cinereum is typically between March and July.[12] The species in the genus Armases are known as ovigerous, meaning they carry their eggs while they undergo embryonic development.[11][13] Armases cinereum produce between 2,000 and 12,000 eggs in a brood.[14] This number is dependent on fecundity which is proportional to the size of the female producing the eggs.[11] Additionally fecundity represents the energy investment an individual must make to produce a brood of eggs.[14] Eggs are energetically expensive to produce and being ovigerous in nature adds to the energy expenditure. When these eggs hatch larva called zoea emerge.[11] Zoea are planktonic crab larvae with their trait characteristic being a large spine positioned dorsally.[11] Crab zoea will grow and molt several times before they move into their next life stage called the megalopa stage.[11] In this stage the eyes become positioned on eyestalks, a carapace is formed, and the abdomen becomes positioned outward from the carapace posteriorly.[11] The next time the crab molts it will become a juvenile version of its adult form and its larval life stages will be complete.[11]

References

[edit]
  1. ^ a b "ITIS - Report: Armases cinereum". www.itis.gov. Retrieved 2022-04-09.
  2. ^ a b c d e f g h i j k l m n Abele, Lawrence G. (1992). "A review of the Grapsid crab genus Sesarma (Crustacea: Decapoda: Grapsidae) in America, with the description of a new genus". Smithsonian Contributions to Zoology (527): 1–60. doi:10.5479/si.00810282.527. ISSN 0081-0282.
  3. ^ Buck, Tracy L.; Breed, Greg A.; Pennings, Steven C.; Chase, Margo E.; Zimmer, Martin; Carefoot, Thomas H. (2003-07-29). "Diet choice in an omnivorous salt-marsh crab: different food types, body size, and habitat complexity". Journal of Experimental Marine Biology and Ecology. 292 (1): 103–116. doi:10.1016/S0022-0981(03)00146-1. ISSN 0022-0981.
  4. ^ Abbas, Eman M.; Abdelsalam, Khaled M.; Mohammed-Geba, Khaled; Ahmed, Hamdy O.; Kato, Mikio (2016-09-01). "Genetic and morphological identification of some crabs from the Gulf of Suez, Northern Red Sea, Egypt". The Egyptian Journal of Aquatic Research. 42 (3): 319–329. doi:10.1016/j.ejar.2016.08.003. ISSN 1687-4285.
  5. ^ Kiskaddon, Erin Paige (2016). Feeding Patterns and Trophic Food Web Dynamics of Armases cinereum Across a Mangrove/Upland Ecotone. USF Tampa Graduate Theses and Dissertations (M.S.).
  6. ^ a b c d e f Kiskaddon, Erin; Chernicky, Kiley; Bell, Susan (2019-02-15). "Resource use by and trophic variability of Armases cinereum (Crustacea, Brachyura) across human-impacted mangrove transition zones". PLOS ONE. 14 (2): e0212448. Bibcode:2019PLoSO..1412448K. doi:10.1371/journal.pone.0212448. ISSN 1932-6203. PMC 6377144. PMID 30768634.
  7. ^ Williams, Austin B. (1984). "Shrimps, Lobsters, and crabs of the Atlantic Coast of the Eastern United States, Maine to Florida". Estuaries. 8 (1): 77. doi:10.2307/1352125. ISSN 0160-8347. JSTOR 1352125. S2CID 83630574.
  8. ^ Zimmer, Martin; Pennings, Steven C.; Buck, Tracy L.; Carefoot, Thomas H. (2004-10-01). "Salt marsh litter and detritivores: A closer look at redundancy". Estuaries. 27 (5): 753–769. doi:10.1007/BF02912038. ISSN 0160-8347. S2CID 10318266.
  9. ^ Pennings, Steven C.; Carefoot, Thomas H.; Siska, Erin L.; Chase, Margo E.; Page, Teresa A. (September 1998). "Feeding Preferences of a Generalist Salt-Marsh crab: Relative Importance of Multiple Plant Traits". Ecology. 79 (6): 1968–1979. doi:10.1890/0012-9658(1998)079[1968:FPOAGS]2.0.CO;2. ISSN 0012-9658.
  10. ^ Bosc, Louis Augustin Guillaume (1828). Histoire naturelle des crustacés, contenant leur description et leurs moeurs: avec figures dessinées d'après nature (in French). Roret, Libraire, Rue Hautefeuille.
  11. ^ a b c d e f g h WEIS, JUDITH S. (2012). Walking Sideways: The Remarkable World of crabs (1st ed.). Cornell University Press. ISBN 978-0-8014-5050-1. JSTOR 10.7591/j.cttn34xc.
  12. ^ Hasek, B. E.; Felder, D. L. (March 2005). "Biochemical composition of ovary, embryo, and hepatopancreas in the grapsoid crabs Armases cinereum and Sesarma nr. reticulatum (Crustacea, Decapoda)". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology. 140 (3): 455–463. doi:10.1016/j.cbpc.2004.11.010. ISSN 1096-4959. PMID 15694594.
  13. ^ Cuesta, José A.; Anger, Klaus (2001). "Larval Morphology of the Sesarmid crab Armases angustipes Dana, 1852 (Decapoda, Brachyura, Grapsoidea)". Journal of Crustacean Biology. 21 (3): 821–838. doi:10.1163/20021975-99990175. ISSN 0278-0372. JSTOR 1549582.
  14. ^ a b Figueiredo, Joana; Penha-Lopes, Gil; Anto, Justin; Narciso, Luís; Lin, Junda (April 2008). "Fecundity, brood loss and egg development through embryogenesis of Armases cinereum (Decapoda: Grapsidae)". Marine Biology. 154 (2): 287–294. doi:10.1007/s00227-008-0922-2. ISSN 1432-1793. S2CID 55307816.