|
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 fam ... [...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 in fresh w ... [...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 pa ...'' References Dromiacea Taxa named by Wilhem de Haan Arthropod superfamilies< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 fossil A fossil (from Classical Latin , ) is any preserved remains, .... 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] |
Dromia Dormia
''Dromia dormia'', the sleepy sponge crab or common sponge crab, is the largest species of sponge crab. It grows to a carapace width of and lives in shallow waters across the Indo-Pacific region. Distribution ''Dromia dormia'' has a widespread distribution in the Indo-Pacific region. Its range extends from East Africa (including Madagascar, the Seychelles and Mauritius) and the Red Sea through the Malay Archipelago, south to Queensland (Australia), north to China and Japan and as far east as Hawaii and French Polynesia. It is mostly found in shallow waters, with the deepest record being . Description ''Dromia dormia'' is the largest species in the family Dromiidae, at up to across the carapace for males, and up to for females. Behaviour Like other related crabs, ''D. dormia'' camouflages itself by carrying a sponge on its back, which it cuts to size with its claws, and then holds in place with its last two pairs of legs. Instead of a sponge, ''D. dormia'' has occasionally be ... [...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 Eubra ... [...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 * Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 *Grapsoidea **G ... [...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 ''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 d ... showing Cyclodorippoida's placement within Brachyura: References Crabs {{Crab-stub ... [...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 fossils. Below is a 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 d ... showing Raninoidea's placement within Brachyura: References Crabs Taxa named by Wilhem de Haan {{Crab-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homolodromioidea
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 Ecdysis is the moulting of the cuticle in many invertebrates of the clade Ecdysozoa. Since the cuticle of these animals typically forms a largely inelastic exoskeleton, it is shed during growth and a new, larger covering is formed. The remna .... The family comprises two genera, '' Dicranodromia'', which has 18 species, and '' Homolodromia'', with five species. References External links * Dromiacea Decapod families {{crab-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaessneropsoidea
Glaessneropsoidea is a superfamily of fossil crabs. They are found in rocks from Late Jurassic age to Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the .... The 45 species in the superfamily are divided among 11 genera in four families: ;Family Glaessneropsidae Patrulius, 1959 *'' Ekalakia'' Bishop, 1976 *'' Glaessneropsis'' Patrulius, 1959 *'' Rathbunopon'' Stenzel, 1945 *'' Vectis'' Withers, 1946 *'' Verrucarcinus'' Schweitzer & Feldmann, 2009 ;Family Lecythocaridae Schweitzer & Feldmann, 2009 *'' Lecythocaris'' von Meyer, 1860 ;Family Longodromitidae Schweitzer & Feldmann, 2009 *'' Abyssophthalmus'' Schweitzer & Feldmann, 2009 *'' Coelopus'' Étallon, 1861 *'' Longodromites'' Patrulius, 1959 *'' Planoprosopon'' Schweitzer, Feldmann & Lazǎr, 2007 ;Family Nodopro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dakoticancroidea
Dakoticancroidea is a superfamily of fossil crabs, containing six species in five genera, divided into two families. The family Dakoticancridae is only known from North American rocks of Late Cretaceous age, while the single species in the Ibericancridae was found in Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i .... ;Dakoticancridae Rathbun, 1917 *'' Avitelmessus grapsoideus'' Rathbun, 1923 *'' Dakoticancer australis'' Rathbun, 1926 *'' Dakoticancer overana'' Rathbun, 1917 *'' Seorsus wadei'' Bishop, 1988 *'' Tetracarcinus subquadrata'' Weller, 1905 ;Ibericancridae Artal, Guinot, Van Bakel & Castillo, 2008 *'' Ibericancer sanchoi'' Artal, Guinot, Van Bakel & Castillo, 2008 References Dromiacea Santonian first appearances Maastrichtian extinctions Taxa named by Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Crab")
