| Coeloma Temporal range: | |
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| Fossils of Coeloma vigil | |
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| Genus: | Coeloma A. Milne-Edwards, 1865 |
| Type species | |
| Coeloma vigil [1] A. Milne-Edwards, 1865 | |
Coeloma is an extinct genus of crabs belonging to the family Mathildellidae. The genus includes 19 species, [2] distributed among several subgenera, and is in need of revision. [1] The fossil record of the genus extends from the Eocene to the Miocene. [1]
Aeger is a genus of fossil prawns. They first occur in the Early Triassic, and died out at the end of the Late Cretaceous. A total of 21 species are known.
Cancridae is a family of crabs. It comprises six extant genera, and ten exclusively fossil genera, in two subfamilies:
The Majoidea are a superfamily of crabs which includes the various spider crabs.
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. A molecular study using the cytochrome oxidase I gene does not support the monophyly of this genus.
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.
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.
Antrimpos is an extinct genus of crustacean which existed during the Triassic and Jurassic periods. It contains 15 species, including Antrimpos speciosus.
Paleomattea is an extinct genus of prawn, containing the single species Paleomattea deliciosa. The species is only known from the stomach contents of the fish Rhacolepis, which is referred to by the specific epithet deliciosa ("delicious"), and in the generic name, where mattea means "delicacy".
Dromia is a genus of crabs in the family Dromiidae. It contains 6 extant species:
Fordilla is an extinct genus of early bivalves, one of two genera in the extinct family Fordillidae. The genus is known solely from Early Cambrian fossils found in North America, Greenland, Europe, the Middle East, and Asia. The genus currently contains three described species, Fordilla germanica, Fordilla sibirica, and the type species Fordilla troyensis.
Panopeus is a genus of crabs, containing these extant species:
Hepatella is a genus of crabs in the family Aethridae, containing these species:
Speocarcinus is a genus of crabs in the family Pseudorhombilidae, containing six extant species, one fossil species from the Late Miocene, one fossil species from the Eocene (Lutetian) and one fossil species from the Early Eocene (Ypresian):
Zosimus is a genus of crabs in the family Xanthidae, containing the following species:
Eryma is a genus of fossil lobster-like crustaceans, containing 44 species.. Two were preserved in the Solnhofen Limestone in Germany. 42 rest of them were found worldwide oldest to youngest between the Jurassic.
Mathildellidae is family of crabs belonging to the superfamily Goneplacoidea, containing the following genera:
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