Arenaeus cribrarius

Arenaeus cribrarius, the speckled swimming crab, is a species of swimming crab in the family Portunidae.[1][2][3]

Arenaeus cribrarius
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Family:	Portunidae
Genus:	Arenaeus
Species:	A. cribrarius
Binomial name
Arenaeus cribrarius (Lamarck, 1818)

Habitat

The crabs can be found from Massachusetts, U.S. to areas in Argentina.[4] They are common in shallow water on sand in ocean beaches, but can be found in depths up to two hundred feet (60m) deep.[5] They are typically found in temperate or tropical waters between eleven and twenty-nine degrees Celsius with a salinity between twenty-eight and thirty-five PSU.[6] Arenaeus cribrarius often bury themselves entirely in sand, but leave a gap for water to pass to their gills.[5] The crabs maintain the gap by clearing the sand with their claws and hairs around their mouth area.[5] Arenaeus cribrarius is a nocturnal and solitary organism, which only interacts with other crabs of its species when it wants to breed.[6]

Feeding

The Speckled swimming crab eats primarily detritus, but have also been recorded eating fish, mollusks, and other crustaceans.[6] They ambush prey that go near their buried bodies.[6] Speckled swimming crabs have been recorded capturing sea turtle hatchlings.[6] Sea turtles are the primary predator to Arenaeus cribrarius.[6] The crabs use their coloration and spines to ward off such predators.[6]

Anatomy

They share a very similar overall shape with the Atlantic Blue Crab.[5] The carapace of a Speckled swimming crab is light brown, light maroon, or olive with many white or tan irregular round spots.[5] The males tend to be more colorful.[5] The carapace can reach lengths between 4.5 and 6 inches wide (~120-150mm).[5] Each side of the carapace consists of nine lateral teeth with the last extending outward.[5] Between the eye sockets there are six partially fused frontal teeth.[5]

Arenaeus cribrarius has ten legs since it is a part of the order decapoda.[5] The first four pairs of legs have yellow tips and are used for walking.[5] These are referred to as broad pereopods.[5] They fifth pair of pereopods are used for swimming.[5] They are a wide flattened paddle shape.[5] Overall, Arenaeus cribrarius can weigh as much as forty-five grams (1.5 oz).[5]

Reproduction

When the Arenaeus cribrarius reaches sexual maturity around five to seven years of age they begin to mate.[5] Arenaeus cribrarius breed year-round and are polygynandrous.[7] The male crab, who is between molts, will select a premolt female who is expressing courtship behavior.[8] The crabs communicate with one another through chemical, visual, and acoustic cues.[7] The male then carries the female for thirty days in a precopulatory position under his body until the female molts.[6][8] When the female's shell is still soft the male will invert her to position themselves with their abdomens in contact together.[6] The male then transfers his spermatophores to her gonopores.[6] Once mating has occurred, the eggs will spawn around fifty-seven days later and will have an fecundity between 135,000 and 680,000.[8] Nauplia will hatch from the Speckled swimming crab eggs around eighteen days and will grow into the first stage of crab thirteen days later.[8] The average age for a Speckled swimming crab is two years.[8]

Commercial usage

In some parts of the world Arenaeus cribrarius is important in fisheries, particularly along the Brazilian coast.[8] The crab is harvested for its meat and residual proteins are used to produce fertilizers and feed for livestock.[8] Along with the consumption of meat, the Speckled swimming crab is harvested for its biproducts.[8] Chitin can be extracted from the crab and used in products like adhesives, cosmetics, photographic emulsions, and anticoagulants.

References

1. "Arenaeus cribrarius Report". Integrated Taxonomic Information System. Retrieved 2018-05-06.
2. "Arenaeus cribrarius". GBIF. Retrieved 2018-05-06.
3. "Arenaeus cribrarius Species Information". BugGuide.net. Retrieved 2018-05-06.
4. Alexandre Ribeiro da Silva; Barioto, João Gabriel; Grabowski, Raphael Cezar; Antonio Leão Castilho.Biologia; Heidelberg Vol. 72, Iss. 3,  (2017): 325-332.
5. DeVictor, Susan; Knott, David; Growe, Stacie (2010). South Carolina Beachcomber’s Guide - A Guide to the Common Invertebrates, Plants and Natural Artifacts of the South Carolina Seashore. 1000 Assembly Street, Columbia, SC 29201: SCDNR. p. 59.CS1 maint: location (link)
6. S, Abel; oval; Wroblewski, Thomas. "Arenaeus cribrarius (speckled swimming crab)". Animal Diversity Web. Retrieved 2019-07-01.
7. Pinheiro, M., A. Fransozo. 1999. Reproductive behavior of the swimming crab Arenaeus cribrarius (Lamarck, 1818) (Crustacea, Brachyura, Portunidae) in Captivity. Bulletin of Marine Science, 64(2): 243-253.
8. Andrade, Luciana S; Fransozo, Vivian; Bertini, Giovana; Negreiros-Fransozo, Maria L; López-Greco, Laura S.

External links

• Media related to Arenaeus cribrarius at Wikimedia Commons