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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] |
Dungeness Crab
The Dungeness crab (''Metacarcinus magister'') makes up one of the most important seafood industries along the west coast of North America. Its typical range extends from Alaska's Aleutian Islands to Point Conception, near Santa Barbara, California. Dungeness typically grow at their widest point and inhabit eelgrass beds and sandy bottoms. Its common name comes from the Dungeness Spit in the Strait of Juan de Fuca, Washington state, United States, which shelters a shallow bay inhabited by the crabs. Description Dungeness crabs have four pairs of armored legs, two claws, and a wide, hard shell. A Dungeness's legs are shorter compared to other commercial crabs and their claws have a distinctive hook. The claws of the crab are used both as defense and to tear apart large food items. The crab uses its smaller appendages to pass the food particles into its mouth. Once inside the crab's stomach, food is further digested by the " gastric mill", a collection of tooth-like structures. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthropods including decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods (insects and entognathans) emerged deep in the Crustacean group, with the completed pan-group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans ( oligostracans and multicrustaceans). The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tasmanian Giant Crab
The Tasmanian giant crab (''Pseudocarcinus gigas''), also known as the Tasmanian king crab, giant deepwater crab, giant southern crab, queen crab, or bullcrab, is a very large species of crab that resides on rocky and muddy bottoms in the oceans off Southern Australia.Levings, A.H. & P.C. Gill (2010). ''Seasonal Winds Drive Water Temperature Cycle and Migration Patterns of Southern Australian Giant Crab Pseudocarcinus gigas.'' In: G.H. Kruse, G.L. Eckert, R.J. Foy, R.N. Lipcius, B. Sainte-Marie, D.L. Stram, & D. Woodby (eds.), Biology and Management of Exploited Crab Populations under Climate Change. . doi:10.4027/bmecpcc.2010.09 It is the only extant species in the genus '' Pseudocarcinus''. Habitat The Tasmanian giant crab lives on rocky and muddy bottoms in the oceans off Southern Australia on the edge of the continental shelf at depths of . It is most abundant at in the summer and in the winter. The seasonal movements generally follow temperature as it prefers . The full ... [...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] |
Corystes
''Corystes cassivelaunus'', the masked crab, helmet crab or sand crab, is a burrowing crab of the North Atlantic and North Sea from Portugal to Norway, which also occurs in the Mediterranean Sea. It may grow up to long (carapace length). The name "masked crab" derives from the patterns on the carapace which resemble a human face (a case of pareidolia), in a similar manner to '' heikegani''. It is the only species in the genus ''Corystes''. ''C. cassivelaunus'' lives buried in sandy substrates, where it feeds on the infaunal invertebrates such as polychaete worms and bivalve molluscs. It uses its two antennae to form a breathing tube that allows oxygenated water down into the substrate. The cheliped A chela ()also called a claw, nipper, or pinceris a pincer-shaped organ at the end of certain limbs of some arthropods. The name comes from Ancient Greek , through Neo-Latin '. The plural form is chelae. Legs bearing a chela are called chelipeds ...s of males are much longer t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grapsus Grapsus
''Grapsus grapsus'' is one of the most common crabs along the western coast of the Americas. It is known as the red rock crab, or, along with other crabs such as ''Percnon gibbesi'', as the Sally Lightfoot crab. Distribution ''Grapsus grapsus'' is found along the Pacific coast of Mexico, Central America, and South America (as far south as northern Peru), and on nearby islands, including the Galápagos Islands. It is also found along the Atlantic coast of South America, but is replaced in the eastern Atlantic Ocean (Ascension Island and West Africa) by its congener ''Grapsus adscensionis''. Description ''Grapsus grapsus'' is a typically shaped crab, with five pairs of legs, the front two bearing small, blocky, symmetrical Chela (organ), chelae (claws). The other legs are broad and flat, with only the tips touching the substrate. The crab's round, flat carapace is slightly longer than . Young ''G. grapsus'' are black or dark brown in colour and are camouflaged well on the bla ... [...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] |
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] |
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] |
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] |
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 hardened yet. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
