''Callinectes similis'', sometimes called the lesser blue crab or dwarf crab, is a West Atlantic

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

blue crab Blue crab may refer to: * Blue Crab 11, an American sailboat design * ''Callinectes sapidus ''Callinectes sapidus'' (from the Ancient Greek language, Ancient Greek ,"beautiful" + , "swimmer", and Latin , "savory"), the blue crab, Atlantic blue ...

. It was described by

Austin B. Williams Austin Beatty Williams (October 17, 1919 – October 27, 1999) was an American carcinologist, "the acknowledged expert on and leader in studies of the systematics of eastern American decapod crustaceans". Biography Austin B. Williams was born on Oc ...

in 1966.

Description

''Callinectes similis'' is a good swimmer, and its last

pereiopod The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these m ...

s are expanded to

paddle A paddle is a handheld tool with an elongated handle and a flat, widened end (the ''blade'') used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered watercraft by p ...

s with which it swims. Adult males may grow up to a width of , while females may reach . ''Callinectes similis'' is most closely related to '' Callinectes danae'', a species also found in the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

, but whose

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

extends as far south as

Rio Grande do Sul Rio Grande do Sul (, ; ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative units of Brazil#List, fifth-most populous state and the List of Brazilian s ...

, and '' C. ornatus'', a species found from

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

to Rio Grande do Sul. ''C. similis'' is most easily separated from ''C. danae'' and ''C. ornatus'' by the form of the first and second

pleopod The anatomy of a decapod consists of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment – often called a somite – may possess one pair of appendages, although in various groups these m ...

s in males. It can be told apart from the more distantly related '' C. sapidus'' by the number of teeth on the front edge of the

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

, there being six in ''C. similis'' and only four in ''C. sapidus''.

Distribution

''Callinectes similis'' is found in the Western

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

Caribbean Sea The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba ...

and

from the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

. It reaches its northern limit near

Delaware Bay Delaware Bay is the estuary outlet of the Delaware River on the northeast seaboard of the United States, lying between the states of Delaware and New Jersey. It is approximately in area, the bay's freshwater mixes for many miles with the saltw ...

. There has been considerable confusion between the various species of ''

Callinectes ''Callinectes'' is a genus of crabs containing species such as the Atlantic blue crab ''Callinectes sapidus, C. sapidus''. Species References Further reading

* Portunoidea Taxa named by William Stimpson Decapod genera {{Port ...

'', and it now appears that all individuals reported as '' C. danae'' and '' C. ornatus'' from the Gulf of Mexico (with the exception of parts of

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

) are actually ''C. similis''.

Ecology

''Callinectes similis'' lives in

marsh In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in genera ...

es and

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

, being the dominant crab in open

bay A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a ''gulf'', ''sea'', ''sound'', or ''bight''. A ''cove'' is a small, ci ...

s. The species is limited to

salinities Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ...

of at least 15

‰ The phrase per mille () indicates parts per thousand. The associated symbol is , similar to a per cent sign but with an extra zero in the divisor. Major dictionaries do not agree on the spelling, giving other options of per mil, per mill, pe ...

, and

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

may also affect reproduction. The diet of ''C. similis'' consists of a variety of foodstuffs, including

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...

s, other

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s including ''

Farfantepenaeus aztecus ''Farfantepenaeus aztecus'' is a species of marine penaeid shrimps found around the east coast of the US and Mexico. They are an important commercial species in the US. The FAO refers to them as the northern brown shrimp; other common names, us ...

'' and ''

Portunus gibbesii ''Portunus'' is a genus of crabs which includes several important species for fisheries, such as the blue swimming crab and the Gazami crab. Other species, such as the three-spotted crab are caught as bycatch. The genus ''Portunus'' contain ...

'',

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

such as ''

Mulinia lateralis ''Mulinia lateralis'', the dwarf surf clam or coot clam, is a species of small saltwater clam, a bivalve mollusc in the family Mactridae. It occurs in the western Atlantic Ocean and the Caribbean Sea. Description ''Mulinia lateralis'' has a some ...

'', and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

Spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

takes place in the spring and fall, with females returning to estuaries to release their eggs. Ovigerous (egg-carrying) females carry an average of more than 250,000 eggs.

Fishery

Although it is not usually targeted because of its relatively small size, ''C. similis'' is sometimes caught alongside ''C. sapidus''.

References

{{Taxonbar, from=Q3791445 Portunoidea Crabs of the Atlantic Ocean Crustaceans described in 1966 Edible crustaceans