Actinotocarcinus | |
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Subfamily: | Actinotocarcininae |
Genus: | Actinotocarcinus Jenkins, 1974 [2] |
Type species | |
Actinotocarcinus chidgeyi Jenkins, 1974 | |
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Actinotocarcinus is an extinct genus of Miocene crab, and is the only genus in the subfamily Actinotocarcininae of the family Epialtidae, [1] though was originally classified in the family Majidae. [3] Actinotocarcinus comprises two species, A. chidgeyi, and A. maclauchlani, both from Miocene-aged marine strata of New Zealand. [2] [4]
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. They are sought by Crab fisheries, and are considered a delicacy in Japan. Conservation efforts are being put forth to protect these creatures and their population from the dangers of overfishing.
The Achelata is an infra-order of the decapod crustaceans, holding the spiny lobsters, slipper lobsters and their fossil relatives.
Cancridae is a family of crabs. It comprises six extant genera, and ten exclusively fossil genera, in two subfamilies:
Hippoidea is a superfamily of decapod crustaceans known as sand crabs, mole crabs, sand bugs, or sand fleas.
Archaeogeryon is an extinct genus of crab from the Miocene, the type species in the genus is Archaeogeryon peruvianus. Despite the species name, the crab is only known from the Guadal Formation, Chile.
Hexapodidae is a family of crabs, the only family in the superfamily Hexapodoidea. It has traditionally been treated as a subfamily of the family Goneplacidae, and was originally described as a subfamily of Pinnotheridae. Its members can be distinguished from all other true crabs by the reduction of the thorax, such that only seven sternites are exposed, and only four pairs of pereiopods are present. Not counting the enlarged pair of claws, this leaves only six walking legs, from which the type genus Hexapus, and therefore the whole family, takes its name. Some anomuran "crabs", such as porcelain crabs and king crabs also have only four visible pairs of legs. With the exception of Stevea williamsi, from Mexico, all the extant members are found either in the Indo-Pacific oceans, or around the coast of Africa.
Albuneidae is a little-known family of specialized burrowing sand crabs. There are 50 extant species as well as nine fossil species that have been described. Fossil specimens have been described from the Cretaceous, Miocene and Oligocene.
Metacarcinus is a genus of crabs formerly included in the genus Cancer. It includes nine exclusively fossil species and five extant species, of which four are also known from the fossil record. The monophyly of this genus was not supported by a molecular study using the cytochrome oxidase I gene.
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.
Branchioplax is an extinct genus of crab which existed in Alaska and Washington during the Eocene period. It was first named by Mary Rathbun in 1916, and contains ten species , including Branchioplax washingtoniana from the Hoko River Formation, Branchioplax carmanahensis, and Branchioplax ballingi.
Actumnus is a genus of crabs in the family Pilumnidae. Alongside the 28 extant species, it has a fossil record extending back into the Miocene.
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.
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.
Hepatella is a genus of crabs in the family Aethridae, containing these species:
Hepatus is a genus of crabs in the family Aethridae, containing seven extant species, plus some fossil species:
Ashtoret is a genus of crabs in the family Matutidae, containing the following species:
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.
Cyclograpsus is a genus of crabs, containing the following species:
Goneplax is a genus of crabs, containing the following extant species:
Coeloma is an extinct genus of crabs belonging to the family Mathildellidae. The genus includes 19 species, distributed among several subgenera, and is in need of revision. The fossil record of the genus extends from the Eocene to the Miocene.