Gecarcinus ruricola | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Crustacea |
Class: | Malacostraca |
Order: | Decapoda |
Suborder: | Pleocyemata |
Infraorder: | Brachyura |
Family: | Gecarcinidae |
Genus: | Gecarcinus |
Species: | G. ruricola |
Binomial name | |
Gecarcinus ruricola | |
Synonyms [2] | |
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Gecarcinus ruricola is a species of terrestrial crab. It is the most terrestrial of the Caribbean land crabs, [3] and is found from western Cuba across the Antilles as far east as Barbados. Common names for G. ruricola include the purple land crab, [1] black land crab, [3] red land crab, [4] and zombie crab. [5]
Four colour morphs exist within the species - black, red, yellow, and green. [6] The carapace of G. ruricola grows in width at a rate of about 1 in (25 mm) per year, with the crabs reaching maturity after 5 years, and living for up to 10 years in total. [6] G. ruricola crabs have a number of adaptations to terrestrial life, mostly regarding water conservation. They are nocturnal, to prevent the hot sun from drying them out. They also have a "nephritic pad", onto which urine is released, to be cleaned by microbes before the water is then reabsorbed. [7]
G. ruricola is found across much of the Caribbean, from Cuba and the Bahamas in the west through the Antilles to Barbados in the east. It has been reported from Florida and Nicaragua, but few confirmed examples exist from the mainland; Loggerhead Key in the Dry Tortugas marks the northernmost limit of its island distribution, which extends across the Bahamas and Cuba, through the Greater and Lesser Antilles, to Barbados. Outlying populations exist on Curaçao, in the Swan Islands off Honduras, Half Moon Caye of Belize, and the Archipelago of San Andrés, Providencia and Santa Catalina off the Colombian coast. [3]
It can be found at great distances from the sea, and at high altitudes; it has been observed above 300 m (980 ft) on the island of Dominica, and at over 1,000 m (3,300 ft) on Jamaica. [3]
The eggs of G. ruricola hatch in the sea, [6] where the larvae live as plankton. The return of the larvae to land seems to be infrequent, but when they do return, they return as megalopa larvae, in sufficient numbers to turn roads red. [8] They move at speeds of 1–2 m/s (2.2–4.5 mph), or faster if startled. [9] For the next three years, the young crabs live in burrows inhabited by other crabs, and eat food brought back to the burrow by the older crab. [6]
After mating, mass migrations occur, with the females returning to the sea to release their fertilised eggs. A typical female carries around 85,000 eggs. [8]
G. ruricola is an omnivorous scavenger, [6] feeding mostly on nitrogen-poor plant matter. [8]
The meat of G. ruricola is rich in protein, and has often been harvested by local people. Other predators may include birds, although information is scarce. When confronted, they rear up and hold their open claws outwards in a defensive posture. [6]
G. ruricola is the host organism for two species of commensal flies in the genus Drosophila . [10] They were first observed on Montserrat by Henry Guernsey Hubbard in 1894, and presented at a scientific meeting later that year (where the crab was misidentified as Cardisoma guanhumi ), but no further research was conducted until 1955, when specimens were again collected, this time from Mona Island, and named as Drosophila carcinophila by M. R. Wheeler. [11]
In 1967, a second species of fly, Drosophila endobranchia , was discovered on G. ruricola, although it also inhabits the closely related species G. lateralis . D. endrobranchia is not closely related to D. carcinophila, and this trait appears to have evolved convergently. (A third species of fly, Lissocephala powelli , has evolved a similar habit on Christmas Island, where it lives on the land crabs Gecarcoidea lalandii , Geograpsus crinipes , and Cardisoma carnifex , and the terrestrial hermit crab Birgus latro .) D. endobranchia evolved from a group of species that breeds on fungi or bark, while D. carcinophila evolved from a group that breeds on cacti. [10]
The flies spend most of their lives on the crab, and are reluctant to leave. They do not need to flee predators, because the crabs they inhabit are fast animals and will flee: [7]
The flies … hardly move at all, are extremely reluctant in leaving their host crabs and are hard pushed to take flight. Although the flies are sluggish, the crabs on which they reside are anything but. Chasing after crabs through a pitch-black jungle (growing on a razor-sharp labyrinthine limestone ground), while trying to aspirate flies from their carapaces is not trivial. Obtaining large amounts of flies in this way is simply a nightmare.
The eggs are laid around the crab's compound eyes; the first-instar larvae migrate to the crab's nephritic pad, and live there, feeding on the microbes that cleanse the crab's urine. The second instar is spent in the crab's gill chamber. The third instar has the larvae return to the mouthparts before falling to the ground to pupate. [7]
Carl Linnaeus described the species in 1758 (the starting point for zoological nomenclature), noting the species' annual migrations from the forests to the coast (Habitat in America, sylvas vastissimis agminibus quotannis deserens littora maris petiturus: "lives in America; every year, an army marches out of the forests towards the sea"). [12]
G. ruricola appeared on two African postage stamps for the International Year of the Ocean in 1998, under the name "mountain crab". These were a Tanzanian stamp worth TSh 500/= and a Ugandan stamp worth USh 250/=. [13]
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period.
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an asymmetric abdomen concealed by a snug-fitting shell. Hermit crabs' soft (non-calcified) abdominal exoskeleton means they must occupy shelter produced by other organisms or risk being defenseless.
The genus Coenobita contains 17 species of terrestrial hermit crabs. Several species in this genus are kept as pets.
Grapsus grapsus is one of the most common crabs along the western coast of the Americas. It is known as the red rock crab, or, along with other crabs such as Percnon gibbesi, as the Sally Lightfoot crab.
Tuerkayana hirtipes is a species of terrestrial crab.
Discoplax longipes is a species of terrestrial crab. It is found in karstic caves on Pacific islands and ranges from the Loyalty Islands to French Polynesia. Mating occurs in the caves, after which the females migrate to the sea to release their fertilised eggs. The genus Discoplax was for a long time synonymised with Cardisoma, but was resurrected in the late 20th century.
The fauna of Barbados comprises all the animal species inhabiting the island of Barbados and its surrounding waters. Barbados has less biodiversity than the other Antilles. Human activities are responsible for the change in the composition of the fauna, in particular, the replacement of native species. Species that are able to adapt to human presence have survived.
Cardisoma guanhumi, also known as the blue land crab, is a species of land crab found in tropical and subtopical estuaries and other maritime areas of land along the Atlantic coast of the Americas from Brazil and Colombia, through the Caribbean and Gulf of Mexico, to the Bahamas, and north to Ponce Inlet, Florida Princess Place Preserve on the Palm Coast, and Bermuda. The species varies in colour from dark blue to brown or pale grey, and may grow to 15 centimetres (6 in) in carapace width and weigh over 500 grams (18 oz).
Cardisoma armatum is a species of terrestrial crab.
Gecarcinus lateralis, also known by the common names blackback land crab, Bermuda land crab, red land crab and moon crab, is a colourful crab from the family Gecarcinidae.
Gecarcinus is the type genus of the land crab family Gecarcinidae. They are found in warmer coastal regions of the Americas, including islands in the Caribbean. Four species from oceanic islands were formerly included in Gecarcinus as the subgenus Johngarthia, but are now treated as a separate genus, Johngarthia. While all members of this genus are largely terrestrial, they have to return to the ocean to breed. They are often colourful, with reddish, orange, purple, yellowish, whitish, or blackish being the dominating hues. This has resulted in some species, notably G. quadratus and G. lateralis, gaining a level of popularity in the pet trade.
Drosophila endobranchia is a species of fly in the family Drosophilidae. The species, which is endemic to Grand Cayman, was discovered in 1966 and not found again until 2007, when it was rediscovered in the mouth region of a land crab.
The coconut crab is a species of terrestrial hermit crab, also known as the robber crab or palm thief. It is the largest terrestrial arthropod in the world, with a weight of up to 4.1 kg (9 lb). It can grow to up to 1 m in width from the tip of one leg to the tip of another. It is found on islands across the Indian Ocean, and parts of the Pacific Ocean as far east as the Gambier Islands, Pitcairn Islands and Caroline Island, similar to the distribution of the coconut palm; it has been extirpated from most areas with a significant human population, including mainland Australia and Madagascar. Coconut crabs also live on islands off the coast of Africa around Zanzibar.
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow. The larvae of crustaceans often bear little resemblance to the adult, and there are still cases where it is not known what larvae will grow into what adults. This is especially true of crustaceans which live as benthic adults, more-so than where the larvae are planktonic, and thereby easily caught.
Johngarthia lagostoma is a species of terrestrial crab that lives on Ascension Island and three other islands in the South Atlantic. It grows to a carapace width of 110 mm (4.3 in) on Ascension Island, where it is the largest native land animal. It exists in two distinct colour morphs, one yellow and one purple, with few intermediates. The yellow morph dominates on Ascension Island, while the purple morph is more frequent on Rocas Atoll. The species differs from other Johngarthia species by the form of the third maxilliped.
Johngarthia weileri is a species of land crab in the genus Johngarthia from the eastern Atlantic Ocean.
A number of lineages of crabs have evolved to live predominantly on land. Examples of terrestrial crabs are found in the families Gecarcinidae and Gecarcinucidae, as well as in selected genera from other families, such as Sesarma, although the term "land crab" is often used to mean solely the family Gecarcinidae.
Guinotia dentata, commonly known as cyrique, is a West Indian species of freshwater crab in the family Pseudothelphusidae. They have few predators. They are easily caught and thus are used locally as a food source.
Coenobita rubescens is a species of terrestrial (land-living) hermit crab, family Coenobitidae.