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Dromioidea
Dromioidea is a superfamily of crabs mostly found in Madagascar. Dromioidea belongs the group Dromiacea, taxonomically ranked as a section, which is the most basal grouping of Brachyura crabs. Dromiacea likely diverged from the rest of Brachyura around the Late Triassic or Early Jurassic, and the earliest fossils attributable to the Dromioidea date from the Late Jurassic. The below cladogram shows Dromioidea's placement within Dromiacea: Recent studies have found that the Dromioidea family Dromiidae may be paraphyletic with respect to Dynomenidae Dynomenidae is a family of crabs in the superfamily Dromioidea mostly found in Madagascar. There are nineteen genera in this family: five extant and fourteen known from fossils: *'' Acanthodromia'' A. Milne-Edwards, 1880 *'' Dynomene'' Desmare .... References Dromiacea Extant Late Jurassic first appearances Taxa named by Wilhem de Haan Arthropod superfamilies {{crab-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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoloidea
Homoloidea is a superfamily of dromiacean crabs. Homoloidea belongs the group Dromiacea, taxonomically ranked as a section, and is the sister group to Dromioidea. Dromiacea is the most basal grouping of Brachyura crabs, and likely diverged from the rest of Brachyura around the Late Triassic or Early Jurassic. The close relation between Homoloidea and Dromioidea is primarily established through ultrastructural characteristics of the sperm. The below cladogram shows Homoloidea's placement within Dromiacea: Recent studies have found that the Homoloidea family Homolidae is paraphyletic with respect to Latreilliidae. See also *''Homola barbata ''Homola barbata'' is a species of crab in the family Homolidae. Description They usually have squarish carapaces with forward-pointing spines along the upper front edges. The animal's chelipeds are shorter than their other legs (the back pair ...'' References Dromiacea Taxa named by Wilhem de Haan Arthropod superfamilie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting " tail" ( abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. They first appeared during the Jurassic Period. Description Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a pair of chelae (claws). Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to . Several other groups of crustaceans with similar appearances – such as king crabs and porcelain crabs – are not true crabs, but have evolved features similar to true crabs through a process known as carcinisation. Environment Crabs are found in all of the world's oceans, as well as i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynomenidae
Dynomenidae is a family of crabs in the superfamily Dromioidea mostly found in Madagascar. There are nineteen genera in this family: five extant and fourteen known from fossils: *'' Acanthodromia'' A. Milne-Edwards, 1880 *'' Dynomene'' Desmarest, 1823 *''Hirsutodynomene Hirsutodynomene is a genus of crabs in the family Dynomenidae. All species in this genus except the newest one belonged to the genus '' Dynomene''. These two genera form the subfamilia Dynomeninae. The type species of this genus is: '' Dynomene ...'' McLay, 1999 *'' Metadynomene'' McLay, 1999 *'' Paradynomene'' Sakai, 1963 *†'' Acanthodiaulax'' Schweitzer ''et al.'', 2003 *†'' Basinotopus'' M'Coy, 1849 *†'' Cyamocarcinus'' Bittner, 1883 *†'' Dromiopsis'' Reuss, 1858 *†'' Dynomenopsis'' Secretan, 1972 *†'' Eotrachynotocarcinus'' Beschin ''et al.'', 2007 *†'' Gemmellarocarcinus'' Checchia-Rispoli, 1905 *†'' Graptocarcinus'' Roemer, 1887 *†'' Kierionopsis'' Davidson, 1966 *†'' Maurimia'' Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dromia Personata
''Dromia personata,'' also known as the sponge crab or sleepy crab, is a species of crab found in the North Sea, the Mediterranean Sea, and connecting parts of the northeastern Atlantic Ocean. Like most other epibenthic crustaceans, the biomass of this species is especially dense in the Mediterranean continental shelf. It mainly resides from the lower shore to a depth of 50 meters (164 ft), often in caves. Occasionally, they are found living in depths as low as 110 meters (360 ft). They serve as prey for octopus, starfish, and other fish. Their last two pairs of legs are positioned dorsally, and are used to hold a sponge in place as camouflage. Reproduction and development ''Dromia personata'' is a gonochoric species. Courtship prior to copulation is commonly practiced through visual, olfactory, or tactile means. Sperm can only be transferred directly from the male's gonopod into the ovigerous female after a molting period, when her exoskeleton has not harden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age. In the past, ''Malm'' was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units. Subdivisions The Late Jurassic is divided into three ages, which correspond with the three (faunal) stages of Upper Jurassic rock: Paleogeography During the Late Jurassic Epoch, Pangaea broke up into two supercontinents, Laurasia to the north, and Gondwana to the south. The result of this break-up was the spawning of the Atlantic Ocean. However, at this time, the Atlantic Ocean was relatively narrow. Life forms of the epoch This epoch is well known for many famous types of din ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Late Jurassic First Appearances
Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, such as an extant species * Extant Theatre Company, a disability arts organisation * Extant (TV series), ''Extant'' (TV series), an American television series * Hank Hall, also known as Extant, a DC Comics supervillain See also * Extent (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of Synapomorphy and apomorphy, synapomorphies and symplesiomorphy, symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia (reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latreilliidae
Latreilliidae is a small family of crabs. They are relatively small, long-legged crabs found on soft bottoms at depths of up in mostly tropical and subtemperate waters around the world. Their carapace is very small and doesn’t cover the bases of their legs, which protrude from the cephalothorax in a spider-like manner. The family and its type genus are named after Pierre André Latreille. The oldest known fossils from the Latreillidae have been dated to the middle of the Cretaceous period. It comprises seven extant species. Distribution Most species in Latreilliidae are relatively concentrated in the Indo-Pacific region, but sometimes may be found in adjacent regions. They are usually found in the mesopelagic zone of these regions. Five of the seven species are located mainly in this region(''L. metanesa, L. pennifera, L. valida, E. australiensis,'' and ''E. phalangium''). Sightings of some of these species have been reported outside of this region: ''L. metanesa'' have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homolidae
The family Homolidae, known as carrier crabs or porter crabs, contains 14 genera of marine crabs. They mostly live on the continental slope and continental shelf, and are rarely encountered. Members of the Homolidae have their fifth pereiopods (last pair of walking legs) in a sub-dorsal position, which allows them to hold objects in place over the rear half of the carapace. The objects carried include sponges, black corals and gorgonians, and this behaviour may be a defence mechanism against predators. Some species have been observed carrying living sea urchins in a symbiotic relationship which allows them to benefit from the protection of the urchin's dangerous spikes. Genera A total of 14 genera are currently recognised in the family: *'' Dagnaudus'' Guinot & Richer de Forges, 1995 *'' Gordonopsis'' Guinot & Richer de Forges, 1995 *''Homola'' Leach, 1816 *'' Homolax'' Alcock, 1899 *'' Homolochunia'' Doflein, 1904 *'' Homologenus'' A. Milne-Edwards, in Henderson, 1888 *'' Ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books by decree in 1586, it is the second oldest university press after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics known as the Delegates of the Press, who are appointed by the vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, opposite Somerville College, in the inner suburb of Jericho. For the last 500 years, OUP has primarily focused on the publication of pedagogical texts and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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