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Bathyraja Albomaculata
The white-dotted skate (''Bathyraja albomaculata'') is a species of skate in the family Arhynchobatidae. It is found in the south-western Atlantic off the coast of Uruguay, Argentina and the Falkland Islands and uncommonly off Chile (Guamblin Island) in the south-eastern Pacific Ocean, at depths ranging from 55 to 861 metres. Males reach maturity at the age of about 11 years and females about 10 years. At maturity the total length of males is about 62.8 cm and females 65.3 cm. The oldest reported specimen was 17 years old. The maximum length has been estimated to be almost one metre. It is oviparous. Egg capsules are oblong having horned corners, the horns at the back end appear first and are longer, and thinner than the front ones. Capsules are barrel-shaped, quite smooth, yellow-brown when freshly laid, but they get darker. Egg laying has been observed year-round, but most frequently in autumn and winter. The animal eats mainly benthopelagic gammarids and polychaet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Roxborough Norman
John Roxborough Norman (1898, Wandsworth, London – 26 May 1944, Berkhamsted, Hertfordshire) was an English ichthyologist. He started as a clerk in a bank. His lifetime affliction with rheumatic fever began during his military service during the First World War. He entered the British Museum in 1921 where he worked for Charles Tate Regan (1878-1943). From 1939 to 1944, he was in charge of the Natural History Museum at Tring as the Curator of Zoology. Norman was the author of, among others, ''A History of Fishes'' (1931) and ''A Draft Synopsis of the Orders, Families and Genera of Recent Fishes'' (1957). He was considered closer to Albert Günther (1830-1914) than to Regan. See also *:Taxa named by John Roxborough Norman References Aldemaro Romero Home Page (Archived on 14 September 2006) *Translated from the French Wikipedia article 1898 births 1944 deaths English ichthyologists People from Wandsworth 20th-century British zoologists British military personnel of World War ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaetes
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known from fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By John Roxborough Norman
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in '' Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of Chile
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a vertebrate, true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed placodermi, external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of Uruguay
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of Argentina
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathyraja
''Bathyraja'' is a large genus of skates in the family Arhynchobatidae. Species There are 55 recognized species in this genus:Orr, J.W., Stevenson, D.E., Hoff, G.R., Spies, I. & McEachran, J.D. (2011)Bathyraja panthera, ''a new species of skate (Rajidae: Arhynchobatinae) from the western Aleutian Islands, and resurrection of the subgenus'' Arctoraja ''Ishiyama.'' NOAA Professional Paper NMFS, 11: 50pp * '' Bathyraja abyssicola'' ( Gilbert, 1896) (Deep-sea skate) * '' Bathyraja aguja'' ( Kendall & Radcliffe, 1912) (Aguja skate) * '' Bathyraja albomaculata'' (Norman, 1937) (White-dotted skate) * '' Bathyraja aleutica'' ( Gilbert, 1896) (Aleutian skate) * '' Bathyraja andriashevi'' Dolganov, 1985 (Little-eyed skate) * '' Bathyraja bergi'' Dolganov, 1983 (Bottom skate) * '' Bathyraja brachyurops'' ( Fowler, 1910) (Broadnose skate) * '' Bathyraja cousseauae'' Díaz de Astarloa & Mabragaña, 2004 (Joined-fins skate) * '' Bathyraja diplotaenia'' ( Ishiyama, 1952) (Dusky-pink skate) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopods
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax. Isopods have various feeding methods: some eat dead or decaying plant and animal matter, others are grazers, or filter feeders, a few are predators, and some are internal or external parasites, mostly of fish. Aquatic species mostly live on the seabed or bottom of freshwater bodies of water, but some taxa can swim for a short distance. Terrestrial forms move around by crawling and tend to be found in cool, moist places. Some species are able to roll themselves into a ball as a defense mechanism or to conserve moisture. There are over 10,000 identified species of isopod worldwide, with around 4,500 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gammarid
Gammaridae is a family of amphipods. In North America they are included among the folk taxonomic category of " scuds", and otherwise gammarids is usually used as a common name. They have a wide distribution, centered on Eurasia, and are euryhaline as a lineage, inhabiting fresh to marine waters. Systematics The Gammaridae were for a long time used as a "wastebin taxon", which included numerous genera of gammaridean amphipods that since then have been removed to their own families, such as the Anisogammaridae, Melitidae, Niphargidae. The following genera are currently listed in the family: *'' Akerogammarus'' Derzhavin & Pjatakova, 1967 *'' Albanogammarus'' Ruffo, 1995 *'' Amathillina'' G. O. Sars, 1894 *'' Axelboeckia'' Stebbing, 1899 *''Baku'' Karaman & Barnard, 1979 *'' Cephalogammarus'' Karaman & Barnard, 1979 *'' Chaetogammarus'' Martynov, 1924 *'' Comatogammarus'' Stock, 1981 *'' Condiciogammarus'' G. Karaman, 1984 *'' Dershavinella'' Birstein, 1938 *''Dikerogammarus'' S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthopelagic
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly and extends to the ocean depths, where no light penetrates. Fish The distinction between demersal species of fish and pelagic species is not always clear cut. The Atlantic cod (''Gadus morhua'') is a typical demersal fish, but can also be found in the open water column, and the Atlantic herring (''Clupea harengus'') is predominantly a pelagic species but forms large aggregations near the seabed when it spawns on banks of gravel. Two types of fish inhabit the demersal zone: those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg Case (Chondrichthyes)
An egg case or egg capsule, often colloquially called a mermaid's purse, is the casing that surrounds the eggs of oviparous sharks, skates and chimaeras. Egg cases typically contain one embryo, except for big skate and mottled skate egg cases, which contain up to 7 embryos. Oviparity is completely absent in the superorder Squalomorphii. Description Egg cases are made of collagen protein strands, and are often described as feeling rough and leathery. Some egg cases have a fibrous material covering the outside of the egg case, thought to aid in attachment to substrate. Egg cases without a fibrous outer layer can be striated, bumpy, or smooth and glossy. With the exception of bullhead shark eggs, egg cases are typically rectangular in shape with projections, called horns, at each corner. Depending on the species, egg cases may have one or more tendrils. Development Shortly after internal fertilization, the fertilized ovum enters the partially formed egg case located in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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