Arenaeus cribrarius

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]

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]

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]

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.