| Discoplax rotunda | |
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| Species: | D. rotunda |
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| Discoplax rotunda | |
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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" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. Many other animals with similar names – such as hermit crabs, king crabs, porcelain crabs, horseshoe crabs, and crab lice – are not true crabs, but many have evolved features similar to true crabs in a process of carcinisation.
The Japanese spider crab is a species of marine crab that lives in the waters around Japan. It has the largest leg span of any arthropod. They go through three main larval stages along with a prezoeal stage in order to grow to their great size. The genus Macrocheira contains multiple species. Two fossil species of this genus have been found, Macrocheira ginzanensis and Macrocheira yabei, both from the Miocene of Japan. The diverse taxonomic history is an important part of what these creatures are and how they evolved to be what they are today. These creatures are not isolated however, as they are the subject of fishery and are considered a delicacy. Conservation efforts are being put forth to protect these creatures and their population from the dangers of overfishing.
The Dungeness crab, Metacarcinus magister or Cancer magister, is a species of crab that inhabits eelgrass beds and water bottoms on the west coast of North America. It typically grows to 20 cm (7.9 in) across the carapace and is a popular seafood. Its common name comes from the port of Dungeness, Washington, United States, where it is "a prized crustacean that supports the most valuable fishery on the west coast", and where ocean acidification threatens the marine environment.
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.
The common name blue land crab can be applied to either of two terrestrial crab species:
Belliidae is a family of crabs of the order Decapoda.
Discoplax is a genus of terrestrial crabs. It is very closely related to the genus Cardisoma.
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.
Liocarcinus is a genus of crabs, which includes the flying crab, the vernal crab and several other swimming crabs. It includes 12 species :
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 recognising families such as "Deckeniidae", "Sundathelphusidae", but only two families are currently recognised: Gecarcinucidae and Parathelphusidae.
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.
Homolodromiidae is a family of crabs, the only family in the superfamily Homolodromioidea. In contrast to other crabs, including the closely related Homolidae, there is no strong linea homolica along which the exoskeleton breaks open during ecdysis. The family comprises two genera, Dicranodromia, which has 18 species, and Homolodromia, with five species.
Cheiragonidae is a small family of crabs, sometimes called helmet crabs, placed in its own superfamily, Cheriagonoidea. It comprises three extant species, Erimacrus isenbeckii, Telmessus acutidens and Telmessus cheiragonus, there are no yet evidences of Cheiragonidae in the fossil record. Many of these crabs were formerly treated as members of the Atelecyclidae.
Matutidae is a family of crabs, sometimes called moon crabs, adapted for swimming or digging. They differ from the swimming crabs of the family Portunidae in that all five pairs of legs are flattened, rather than just the last pair, as in Portunidae. Crabs in the Matutidae are aggressive predators.
Eriphioidea is a superfamily of crabs, containing the six families Dairoididae, Eriphiidae, Hypothalassiidae, Menippidae, Oziidae and Platyxanthidae. They are united by a number of characters, including a marked difference in size between the left and right claws, where the larger one has a crushing tooth, and the smaller one does not, and the relative breadth of the male abdomen.
Epialtidae is a family of crabs, containing the subfamilies:
Tuerkayana is a genus of large land crabs. It was created from two members of the genus Cardisoma and two members of Discoplax in late 2018 after a re-examination of the taxonomy of the family Gecarcinidae. Said re-examination also resulted in the creation of the new family Leptograpsodidae for the genus Leptograpsodes.
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