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Skates (fish)
Skates are cartilaginous fish belonging to the family Rajidae in the superorder Batoidea of rays. More than 150 species have been described, in 17 genera.LAST, P.R. & SÉRET, B. & STEHMANN, M.F.W. & WEIGMANN, S. (2016) Skates, Family Rajidae. In: Last, P.R., White, W.T., Carvalho, M.R. de, Séret, B., Stehmann, M.F.W & Naylor, G.J.P (Eds.) Rays of the World. CSIRO Publishing, Melbourne: 204–363 Softnose skates and pygmy skates were previously treated as subfamilies of Rajidae (Arhynchobatinae and Gurgesiellinae), but are now considered as distinct families. Alternatively, the name "skate" is used to refer to the entire order of Rajiformes (families Anacanthobatidae, Arhynchobatidae, Gurgesiellidae and Rajidae). Members of Rajidae are distinguished by a stiff snout and a rostrum that is not reduced. Taxonomy and systematics Evolution Skates belong to the ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling those of today' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic Skate
The Arctic skate (''Amblyraja hyperborea'') is a species of fish in the family Rajidae. It lives near the seabed between 140 and 2,500 m deep in the Arctic Ocean and waters around Canada and northern and north-western Europe, in the northern Pacific Ocean, and in waters surrounding Antarctica and New Zealand. The Arctic skate is about 1 m long and is gray-brown with large dark spots. Its underside is white with dark patterns. It has thorns in line from back to near the end of its tail. It is oviparous; its eggs are capsules with hard horns on each corner. It eats all sorts of small animals at the bottom of the sea. Taxonomy This species was first described by Robert Collett in 1879 and named ''Raja hyperborea.'' Conservation The Arctic skate is classified as being of "least concern" by the IUCN Red List of Threatened Species. In New Zealand, the Department of Conservation has classified the Arctic skate as "Not Threatened" under the New Zealand Threat Classification S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentiraja
''Dentiraja'' is a genus of skates native to the oceans around Australia. Members of this genus usually grow up to a maximum of 35 – 70 cm, with the longest being Heald's skate (''Dentiraja healdi''), with a maximum length of about 72 cm. Species There are currently 9 recognized species in this genus: * ''Dentiraja australis'', (Macleay, 1884) (Sydney skate) * ''Dentiraja cerva'' (Whitley, 1939) (white-spotted skate) * '' Dentiraja confusa'' ( Last, 2008) (Australian longnose skate) * ''Dentiraja endeavouri'' ( Last, 2008) (Endeavour skate) * ''Dentiraja falloarga'' ( Last, 2008) (false argus skate) * ''Dentiraja flindersi'' Last & Gledhill, 2008 (pygmy thornback skate) * ''Dentiraja healdi'' ( Last, W. T. White & Pogonoski, 2008) (Heald's skate) * ''Dentiraja lemprieri'' (Richardson, 1845) (Thornback skate) * ''Dentiraja polyommata The argus skate (''Dentiraja polyommata'') is a species of fish in the family Rajidae. This small, up to long, skate is endemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dactylobatus
''Dactylobatus'' is a genus of skates in the family Rajidae. They are found in deep waters in the western Atlantic Ocean from Brazil to the United States, including the Gulf of Mexico. Species Two species are recognized in this genus: * ''Dactylobatus armatus'' B. A. Bean & A. C. Weed, 1909 (skillet skate) * ''Dactylobatus clarkii The hook skate or Clark's fingerskate (''Dactylobatus clarkii'') is a medium-sized (75 cm in length), but poorly known, deepwater skate (fish), skate." Its distribution is considered patchy and covers the western central and southwest Atlan ...'' ( Bigelow & Schroeder, 1958) (hook skate) References {{Taxonbar, from=Q3011717 Rajiformes Ray genera Taxa named by Barton Appler Bean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breviraja
''Breviraja'', commonly known as lightnose skates, is a genus of small skates in the family Rajidae. They are found in deep water of the western Atlantic, including the Gulf of Mexico. Species * ''Breviraja claramaculata'' McEachran & Matheson, 1985 (Brightspot skate) * ''Breviraja colesi'' Bigelow & Schroeder, 1948 (Lightnose skate) * ''Breviraja marklei'' McEachran & Miyake, 1987 (Nova Scotia Skate) * ''Breviraja mouldi'' McEachran & Matheson, 1995 (Blacknose Skate) * ''Breviraja nigriventralis'' McEachran & Matheson, 1985 (Blackbelly skate) * ''Breviraja spinosa ''Breviraja spinosa'', commonly known as the spinose skate, is a species of ray in the family Rajidae. References *John D. McEachran and Richard E. Matheson, Jr., ''Polychromatism and Polymorphism in Breviraja spinosa (Elasmobranchii, Rajiform ...'' Bigelow & Schroeder, 1950 (Spinose skate) References * * Rajiformes Ray genera Taxa named by Henry Bryant Bigelow Taxa named by William Char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beringraja
''Beringraja'' is a genus of skates in the family Rajidae with up to six described species. Formerly, they were included in the genus '' Raja'' until 2012, when the genus ''Beringraja'' was erected for the two species which had multiple embryos per egg capsule. Genetic evidence has led to four additional species being proposed for inclusion in the genus, although this issue has not be completely resolved.Last, P. R., S. Weigmann and L. Yang 2016. Changes to the nomenclature of the skates (Chondrichthyes: Rajiformes). In: Last and Yearsley (eds.). Rays of the World: Supplementary Information. CSIRO Special Publication. 11-34. These large skates are found in the North Pacific. Species Up to six species are in the genus: * Big skate (''B. binoculata'') * Cortez' ray (''B. cortezensis'') * California ray (''B. inornata'') * Longnose skate (''B. rhina'') * Mottled skate (''B. pulchra'') * Starry skate ''Raja stellulata'', commonly known as the Pacific starry skate, roc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amblyraja
''Amblyraja'' is a genus of skates that primarily are found in the Atlantic, but species also occur in the East and North Pacific, the Arabian Sea, the sub-Antarctic, and off Southern Australia and New Zealand. Species Ten recognized species are placed in this genus: * ''Amblyraja badia'' (Garman, 1899) (broad skate) * ''Amblyraja doellojuradoi'' ( Pozzi, 1935) (southern thorny skate) * ''Amblyraja frerichsi'' ( G. Krefft, 1968) (thickbody skate) * ''Amblyraja georgiana'' (Norman, 1938) (Antarctic starry skate) * ''Amblyraja hyperborea'' ( Collett, 1879) (Arctic skate) * ''Amblyraja jenseni'' ( Bigelow & Schroeder, 1950) (shorttail skate) * ''Amblyraja radiata'' (Donovan, 1808) (thorny skate) * ''Amblyraja reversa'' ( Lloyd, 1906) (reversed skate) * ''Amblyraja robertsi'' ( Hulley, 1970) (bigmouth skate) * ''Amblyraja taaf ''Amblyraja taaf'', commonly known as the whiteleg skate or thorny skate, is a little-known skate Skate or Skates may refer to: Fish *Skate (fish), seve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmobranchii
Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including sharks (superorder Selachii), rays, skates, and sawfish (superorder Batoidea). Members of this subclass are characterised by having five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil. The definition of the clade is unclear with respect to fossil chondrichthyans. It has been used by different authors as equivalent to Neoselachii (the clade including modern sharks and rays and their last common ancestor) or for al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ray (fish)
Batoidea is a superorder of cartilaginous fishes, commonly known as rays. They and their close relatives, the sharks, comprise the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces. Anatomy Batoids are flat-bodied, and, like sharks, are cartilaginous fish, meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batoids have five ventral slot-like body openings called gill slits that lead from the gills, but the Hexatrygonidae have six. Batoid gill slits lie under the pectoral fins on the underside, whereas a shark's are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the guitarfishes and sawfishes, while most sharks have a spindle-shaped body. Many species of batoid have developed their p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawfish
Sawfish, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish with some species reaching lengths of about . They are found worldwide in tropical and subtropical regions in coastal marine and brackish estuarine waters, as well as freshwater rivers and lakes. They are endangered. They should not be confused with sawsharks (order Pristiophoriformes) or the extinct sclerorhynchoids (order Rajiformes) which have a similar appearance, or swordfish (family Xiphiidae) which have a similar name but a very different appearance. Sawfishes are relatively slow breeders and the females give birth to live young. They feed on fish and invertebrates that are detected and captured with the use of their saw. They are generally harmless to humans, but can inflict serious injuries with the saw when captured and defend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic, Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread Anoxic event, oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar, Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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