|
Thoracotremata
Thoracotremata is a clade of crabs, comprising those crabs in which the genital openings in both sexes are on the sternum, rather than on the legs. It comprises 17 families in four superfamilies . Evolution Thoracotremata is the sister group to Heterotremata within the clade Eubrachyura, having diverged during the Cretaceous period. Eubrachyura itself is a subset of the larger clade Brachyura, which consists of all "true crabs". A summary of the high-level internal relationships within Brachyura can be shown in the cladogram below: The internal relationships within Thoracotremata are less certain, with many of the superfamilies found to be invalid. The proposed cladogram below is from analysis by Tsang ''et al'', 2014: Superfamilies and families * Ocypodoidea ** Camptandriidae ** Dotillidae ** Heloeciidae ** Macrophthalmidae ** Mictyridae ** Ocypodidae ** Ucididae ** Xenophthalmidae * Pinnotheroidea ** Pinnotheridae * Cryptochiroidea ** Cryptochiridae * Grapso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropod anatomy), thorax. Their exoskeleton is often Sclerotization, thickened and hard. They generally have Arthropod leg, five pairs of legs, and they have "Pincers (tool), pincers" or "claws" on the ends of the frontmost pair, scientifically termed the ''chelae''. They are present in all the world's oceans, Freshwater crab, in freshwater, and Terrestrial crab, on land, often hiding themselves in small crevices or burrowing into sediment. Crabs are omnivores, feeding on a variety of food, including a significant proportion of Algae eater, algae, as well as Detritivore, detritus and other invertebrates. Crab meat, Crabs are widely consumed by humans as food, with over 1.5 million tonnes Crab fisheries, caught annually. True crabs first appeared ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eubrachyura
Eubrachyura is a group of decapod crustaceans ( ranked as a "section") 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 ( Gecarcinucoidea, Potamoidea). 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 (Middle Jurassic) representative of the group, '' Hebertides jurassica'', ultimately turned out to be Cenozoic in age. Here is a cladogram showing Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterotremata
Heterotremata is a clade of crabs, comprising those crabs in which the genital openings are on the sternum in females, but on the legs in males. It comprises 68 families in 28 superfamilies. Evolution Heterotremata is the sister group to Thoracotremata within the clade Eubrachyura, having diverged during the Cretaceous period. Eubrachyura itself is a subset of the larger clade Brachyura, which consists of all "true crabs". A summary of the high-level internal relationships within Brachyura can be shown in the cladogram below: The internal relationships within Heterotremata are less certain, with many of the superfamilies found to be invalid. The proposed cladogram below is from analysis by Tsang ''et al'', 2014: Superfamilies * Aethroidea * Bellioidea * Bythograeoidea * Calappoidea * Cancroidea * Carpilioidea * Cheiragonoidea * Corystoidea * Dairoidea * Dorippoidea * Eriphioidea * Gecarcinucoidea * Goneplacoidea * Hexapodoidea *Leucosioidea *Majoidea *Orithyioidea *P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclodorippoida
Cyclodorippoida is a group of crabs, ranked as a section. It contains the single superfamily Cyclodorippoidea, which holds three families, Cyclodorippidae, Cymonomidae and Phyllotymolinidae. Below is a cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ... showing Cyclodorippoida's placement within Brachyura: References Crabs {{Cyclodorippoida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromiacea
Dromiacea is a group of crabs, ranked as a section. It contains 240 extant and nearly 300 extinct species. Dromiacea is the most basal grouping of Brachyura crabs, diverging the earliest in the evolutionary history, around the Late Triassic or Early Jurassic. Below is a cladogram showing Dromiacea's placement within Brachyura: The larvae of Dromiacea resemble those of the Anomura more closely than those of other crabs. This may simply reflect their basal position in the crab phylogeny. The superfamily Eocarcinoidea, containing '' Eocarcinus'' and '' Platykotta'', was previously considered to be a member of the Dromiacea, but has since been transferred to the Anomura. The fossil record of Dromiacea reaches back at least as far as the Jurassic, and, if '' Imocaris'' is indeed a member, into the Carboniferous. Dromiacea primarily consists of two groups of superfamilies - Dromioidea and Homoloidea. See the below cladogram: Recent studies have found that some of the fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raninoida
Raninoida is a taxonomic section of the crabs, containing a single superfamily, Raninoidea. This group of crabs is unlike most, with the abdomen not being folded under the thorax. It comprises 46 extant species, and nearly 200 species known only from fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...s. Below is a cladogram showing Raninoidea's placement within Brachyura: References Crabs Taxa named by Wilhem de Haan {{Raninoida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gecarcinidae
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. The family contains these genera: * '' Cardisoma'' * ''Discoplax ''Discoplax'' is a genus of terrestrial crabs. It is very closely related to the genera '' Cardisoma'' and '' Tuerkayana''. ''Discoplax'' contains the following species: References Further reading * Grapsoidea Terrestrial crustac ...'' * '' Epigrapsus'' * '' Gecarcinus'' * '' Gecarcoidea'' * '' Johng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagusiidae
The Plagusiidae are a family (biology), family of crabs, formerly treated as a subfamily of the family Grapsidae, but have since been considered sufficiently distinct to be a family in their own right. The family Plagusiidae used to include a subfamily Plagusiinae, comprising the genera ''Percnon'' and ''Plagusia'', which constitute a widespread group of litophilic, intertidal and subtidal crabs that are notorious for their speed and their agility. Six genera are currently included in the family: *''Caligoplagusia'' Fujita & Narusa, 2014 *''Davusia'' Guinot, 2007 *''Euchirograpsus'' H. Milne-Edwards, 1853 *''Guinusia'' Schubart & Cuesta, 2010 *''Miersiograpsus'' Türkay, 1978 *''Plagusia'' Latreille, 1804 References Grapsoidea Decapod families {{Grapsoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyptograpsidae
Glyptograpsidae is a family of crabs belonging to the superfamily Grapsoidea The Grapsoidea are a superfamily of crabs; they are well known and contain many taxa which are terrestrial (land-living), semiterrestrial (taking to the sea only for reproduction), or limnic (living in fresh water). Another well-known member wit .... Genera: * '' Glyptograpsus'' Smith, 1870 * '' Platychirograpsus'' de Man, 1896 References Crabs Decapod families {{brachyura-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocypodidae
The Ocypodidae is a family of semiterrestrial crabs that includes ghost crabs and fiddler crabs. These crabs are found along tropical and temperate shorelines worldwide. Some genera previously classified within the Ocypodidae family have been reclassified into separate families within the superfamily Ocypoidea, such as Dotillidae and Macrophthalmidae. In 2016, the genus Uca was divided into 13 genera through the elevation of its subgenera to genus status, among other taxonomic changes. Further refinements have been made to the family's organization, resulting in 4 subfamilies, approximately 13 extant genera, and around 180 described species as of 2020. The majority of the Ocypodidae species are fiddler crabs, the exceptions being the members of the genus '' Ocypode'', ghost crabs, and the genus '' Ucides'', mangrove crabs. Genera These genera belong to the family Ocypodidae: * '' Afruca'' Crane, 1975 * '' Austruca'' Bott, 1973 * '' Cranuca'' Beinlich & von Hagen, 2006 * '' G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sesarmidae
The Sesarmidae are a family of crabs, previously included in the Grapsidae by many authors. Several species, namely in '' Geosesarma'', '' Metopaulias'', and '' Sesarma'', are true terrestrial crabs. They do not need to return to the sea even for breeding. Genera The family contains these genera: *''Aratus Aratus (; ; c. 315/310 240 BC) was a Greek didactic poet. His major extant work is his hexameter poem ''Phenomena'' (, ''Phainómena'', "Appearances"; ), the first half of which is a verse setting of a lost work of the same name by Eudoxus of Cn ...'' *'' Armases'' *'' Bresedium'' *'' Chiromantes'' *'' Clistocoeloma'' *'' Contusarma'' *'' Cristarma'' *'' Danarma'' *'' Episesarma'' *'' Fasciarma'' *'' Geosesarma'' *'' Guinearma'' *'' Haberma'' *'' Karstarma'' *'' Labuanium'' *'' Leptarma'' *'' Manarma'' *'' Metagrapsus'' *'' Metasesarma'' *'' Metopaulias'' *'' Miersarma'' *'' Migmarma'' *'' Muradium'' *'' Namlacium'' *'' Nanosesarma'' *'' Neosarmati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mictyridae
''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 A corkscrew is a tool for drawing Cork (plug), corks from wine bottles and other household bottles that may be sealed with corks. In its traditional form, a corkscrew simply consists of a pointed metallic helix (often called the "worm") attach ... pattern, leaving many small round pellets of sand behind them. Species The genus contains eight species: The predictable behaviour of these crabs has led them to be used in experiments in a form of billiard ball computer. References Ocypodoidea Decapod genera {{Ocypodoidea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
