| Discoplax rotunda | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Family: | Gecarcinidae |
| Genus: | Discoplax |
| Species: | D. rotunda |
| Binomial name | |
| Discoplax rotunda | |
| Synonyms | |
| |
Discoplax rotunda is a species of land crab in the genus Discoplax found in the Pacific Ocean.
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land. They are generally covered with a thick exoskeleton. They generally have five pairs of legs, and they have pincer claws on the ends of the frontmost pair. They first appeared during the Jurassic period, around 200 million years ago.
The Japanese spider crab is a species of marine crab and is the biggest one that lives in the waters around Japan. At around 3.7 meters, it has the largest leg-span of any arthropod. The Japanese name for this species is taka-ashi-gani,, literally translating to “tall legs crab”. It goes through three main larval stages along with a prezoeal stage to grow to its great size.
Horseshoe crabs are arthropods of the family Limulidae and are the only surviving xiphosurans. Despite their name, they are not true crabs or even crustaceans. Rather, they are chelicerates. This makes them more closely related to arachnids like spiders, ticks, and scorpions. The body of a horseshoe crab is divided into three main parts: the cephalothorax, abdomen, and telson. The largest of these, the cephalothorax, houses most of the animal's eyes, limbs, and internal organs. It is also where the animal gets its name, as its shape somewhat resembles that of a horseshoe. Horseshoe crabs have changed little in appearance since they first evolved in the Triassic, earning them the title of "living fossil".
The Christmas Island red crab is a species of land crab that is endemic to Christmas Island and Cocos (Keeling) Islands in the Indian Ocean. Although restricted to a relatively small area, an estimated 43.7 million adult red crabs once lived on Christmas Island alone, but the accidental introduction of the yellow crazy ant is believed to have killed about 10–15 million of these in recent years. Christmas Island red crabs make an annual mass migration to the sea to lay their eggs in the ocean. Although its population is under great assault by the ants, as of 2020 the red crab had not been assessed by the International Union for Conservation of Nature (IUCN) and it was not listed on their Red List. The crab's annual mass migration to the sea for spawning is described as an "epic" event. Millions emerge at the same time, halting road traffic and covering the ground in a thick carpet of crabs.
Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width up to 25 centimetres and weigh up to 3 kilograms. C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred on the coasts of the Ireland and Britain, with more than 60,000 tonnes caught annually.
Mictyris is a genus of brightly coloured crabs, placed in its own taxonomical family, the Mictyridae. It inhabits the central Indo-West Pacific region. These crabs congregate on mud flats or beaches in groups of a few thousand, and filter sand or mud for microscopic organisms. They congregate during low tide, and bury themselves in the sand during high tide or whenever they are threatened. This is done in wet sand, and they dig in a corkscrew pattern, leaving many small round pellets of sand behind them.
Tuerkayana hirtipes is a species of terrestrial crab.
Xanthoidea is a superfamily of crabs, comprising seven families. Formerly, a number of other families were included in Xanthoidea, but many of these have since been removed to other superfamilies. These include Carpilioidea, Eriphioidea, Hexapodoidea, Pilumnoidea and Trapezioidea. Even in this reduced state, Xanthoidea remains one of the most species-rich superfamilies of crabs.
Discoplax is a genus of terrestrial crabs. It is very closely related to the genera Cardisoma and Tuerkayana.
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 Gecarcinidae, the land crabs, are a family of true crabs that are adapted for terrestrial existence. Similar to all other crabs, land crabs possess a series of gills. In addition, the part of the carapace covering the gills is inflated and equipped with blood vessels. These organs extract oxygen from the air, analogous to the vertebrate lungs. Adult land crabs are terrestrial, but visit the sea periodically, where they breed and their larvae develop. Land crabs are tropical omnivores which sometimes cause considerable damage to crops. Most land crabs have one of their claws larger than the other.
Cardisoma is a genus of large land crabs. Three species formerly placed in this genus are now placed in Discoplax. The four species that remain in Cardisoma are found in warm coastal regions where they live in burrows. Young individuals are often very colourful with a purple-blue carapace and orange-red legs, but as they grow older the colours tend to fade, and females may be duller than males. Although less extreme than in fiddler crabs, one claw is usually considerably larger than the other. They are omnivores, but primarily feed on plant material.
Gecarcinucoidea is a superfamily of freshwater crabs. Its members have been grouped into families in various ways, with some authors recognizing families such as "Deckeniidae", "Sundathelphusidae", and "Parathelphusidae", but now only the family Gecarcinucidae is currently recognized.
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.
Lybia is a genus of small crabs in the family Xanthidae. Their common names include boxer crabs, boxing crabs and pom-pom crabs. They are notable for their mutualism with sea anemones, which they hold in their claws for defense. In return, the anemones get carried around, which may enable them to capture more food particles with their tentacles. Boxer crabs use at least three species of anemones, including Bundeopsis spp. and Triactis producta. The bonding with the anemone is not needed for survival, however, and boxer crabs have frequently been known to live without them, sometimes substituting other organisms such as sponges and corals for the sea anemones.
The coconut crab is a terrestrial species of giant hermit crab, and is also known as the robber crab or palm thief. It is the largest terrestrial arthropod known, with a weight of up to 4.1 kg (9 lb). The distance from the tip of one leg to the tip of another can be as wide as 1 m. It is found on islands across the Indian and Pacific Oceans, as far east as the Gambier Islands, Pitcairn Islands and Caroline Island and as far west as Zanzibar. While its range broadly shadows the distribution of the coconut palm, the coconut crab has been extirpated from most areas with a significant human population such as mainland Australia and Madagascar.
Eubrachyura is a group of decapod crustaceans comprising the more derived crabs. It is divided into two subsections, based on the position of the genital openings in the two sexes. In the Heterotremata, the openings are on the legs in the males, but on the sternum in females, while in the Thoracotremata, the openings are on the sternum in both sexes. This contrasts with the situation in other decapods, in which the genital openings are always on the legs. Heterotremata is the larger of the two groups, containing the species-rich superfamilies Xanthoidea and Pilumnoidea and all the freshwater crabs. The eubrachyura is well known for actively and constantly building its own burrows. The fossil record of the Eubrachyura extends back to the Cretaceous; the supposed Bathonian representative of the group, Hebertides jurassica, ultimately turned out to be Cenozoic in age.
Dairoidea is a superfamily of crabs, comprising two families which each contain a single genus: Dairidae and Dacryopilumnidae (Dacryopilumnus) .
Hepatus epheliticus, known by various names, including the calico crab and Dolly Varden crab, is a species of crab. It lives in shallow water in the western Atlantic Ocean from the Chesapeake Bay to the Dominican Republic. It has a 3-inch (76 mm)–wide carapace adorned with large red spots with darker outlines.
Blue crab may refer to:
Extant Gecarcinidae species | ||
|---|---|---|
| Cardisoma |   | |
| Discoplax | ||
| Epigrapsus | ||
| Gecarcinus | ||
| Gecarcoidea | ||
| Johngarthia | ||
| Tuerkayana | ||
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