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Narella
''Narella'' (Gray, 1870) is a genus of deep-sea Alcyonacea, soft corals in the family Primnoidae (Milne Edwards, 1857). They are Sessility (motility), sessile, Benthic zone, bottom-dwelling organisms that can be found in all ocean basins, having cosmopolitan distribution. They have a branching appearance. History Etymology The name ''Narella'' is believed to be derived from the latin ''nares,'' meaning nostril, due to the resemblance of the rows of polyps to small noses. Discovery The present understanding of ''Narella'' and its members was only established in the late 20th century. Prior to that, many members of ''Narella'' were categorized into other genera. While the genus itself was described in 1870 by John Edward Gray, the first species in the genus was described in 1860, ''Primnoa regularis'' (now recognized as ''Narella regularis''). In 1887 several new species of ''Narella'' were discovered by Edward Percival WEdward Wright and Théophile Rudolphe Studer, Théophi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Narella Regularis
''Narella'' (Gray, 1870) is a genus of deep-sea soft corals in the family Primnoidae (Milne Edwards, 1857). They are sessile, bottom-dwelling organisms that can be found in all ocean basins, having cosmopolitan distribution. They have a branching appearance. History Etymology The name ''Narella'' is believed to be derived from the latin ''nares,'' meaning nostril, due to the resemblance of the rows of polyps to small noses. Discovery The present understanding of ''Narella'' and its members was only established in the late 20th century. Prior to that, many members of ''Narella'' were categorized into other genera. While the genus itself was described in 1870 by John Edward Gray, the first species in the genus was described in 1860, ''Primnoa regularis'' (now recognized as ''Narella regularis''). In 1887 several new species of ''Narella'' were discovered by Edward Wright and Théophile Studer, but were described as members of new genera ''Stachyodes'' and ''Calypterinus' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primnoidae
Primnoidae is a family (biology), family of Alcyonacea, soft corals. Genera The World Register of Marine Species includes the following Genus, genera in the family: *''Abyssoprimnoa'' Cairns, 2015 *''Acanthoprimnoa'' Cairns & Bayer, 2004 *''Aglaoprimnoa'' Bayer, 1996 *''Ainigmaptilon'' Dean, 1926 *''Armadillogorgia'' Bayer, 1980 *''Arntzia'' López-González, Gili & Orejas, 2002 *''Arthrogorgia'' Kükenthal, 1908 *''Australogorgia'' Cairns & Bayer, 2009 *''Callogorgia'' Gray, 1858 *''Callozostron'' Wright, 1885 *''Calyptrophora'' Gray, 1866 *''Canarya'' Ocaña & van Ofwegen, 2003 *''Candidella'' Bayer, 1954 *''Convexella'' Bayer, 1996 *''Dasystenella'' Versluys, 1906 *''Dicholaphis'' Kinoshita, 1907 *''Fanellia'' Gray, 1870 *''Fannyella'' Gray, 1872 *''Helicoprimnoa'' Cairns, 2012 *''Heptaprimnoa'' Cairns, 2012 *''Metafannyella'' Cairns & Bayer, 2009 *''Metanarella'' Cairns, 2012 *''Microprimnoa'' Bayer & Stefani, 1989 *''Mirostenella'' Bayer, 1988 *''Narella'' Gray, 1870 *''Nar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. Along its core, the Indian Ocean has some large marginal or regional seas such as the Arabian Sea, Laccadive Sea, Bay of Bengal, and Andaman Sea. Etymology The Indian Ocean has been known by its present name since at least 1515 when the Latin form ''Oceanus Orientalis Indicus'' ("Indian Eastern Ocean") is attested, named after Indian subcontinent, India, which projects into it. It was earlier known as the ''Eastern Ocean'', a term that was still in use during the mid-18th century (see map), as opposed to the ''Western Ocean'' (Atlantic Ocean, Atlantic) before the Pacific Ocean, Pacific was surmised. Conversely, Ming treasure voyages, Chinese explorers in the Indian Oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic table) it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium. In the cosmos, magnesium is produced in large, aging stars by the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the interstellar medium where it ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aragonite
Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching helictitic forms called ''flos-ferri'' ("flowers of iron") from their association with the ores at the Carinthian iron mines. Occurrence The type location for aragonite is Molina de Aragón in the Province of Guadalajara in Castilla-La Mancha, Spain, for which it was named in 1797. Aragonite is found in this locality as cyclic twins inside gypsum and marls of the Keuper facies of the Triassic. This type of arago ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
The operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerite
A sclerite (Greek , ', meaning "hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly to the hardened parts of arthropod exoskeletons and the internal spicules of invertebrates such as certain sponges and soft corals. In paleontology, a scleritome is the complete set of sclerites of an organism, often all that is known from fossil invertebrates. Sclerites in combination Sclerites may occur practically isolated in an organism, such as the sting of a cone shell. Also, they can be more or less scattered, such as tufts of defensive sharp, mineralised bristles as in many marine Polychaetes. Or, they can occur as structured, but unconnected or loosely connected arrays, such as the mineral "teeth" in the radula of many Mollusca, the valves of Chitons, the beak of Cephalopod, or the articulated exoskeletons of Arthropoda. When ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyp (zoology)
A polyp in zoology is one of two forms found in the phylum Cnidaria, the other being the medusa. Polyps are roughly cylindrical in shape and elongated at the axis of the vase-shaped body. In solitary polyps, the aboral (opposite to oral) end is attached to the substrate by means of a disc-like holdfast called a pedal disc, while in colonies of polyps it is connected to other polyps, either directly or indirectly. The oral end contains the mouth, and is surrounded by a circlet of tentacles. Classes In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage. In class Scyphozoa, the medusa stage is dominant, and the polyp stage may or may not be present, depending on the family. In those scyphozoans that have the larval planula metamorphose into a polyp, the polyp, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type (biology)
In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the defining features of that particular taxon. In older usage (pre-1900 in botany), a type was a taxon rather than a specimen. A taxon is a scientifically named grouping of organisms with other like organisms, a set that includes some organisms and excludes others, based on a detailed published description (for example a species description) and on the provision of type material, which is usually available to scientists for examination in a major museum research collection, or similar institution. Type specimen According to a precise set of rules laid down in the International Code of Zoological Nomenclature (ICZN) and the International Code of Nomenclature for algae, fungi, and plants (ICN), the scientific name of every taxon is almost al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric Speciation
Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species), such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived from the Greek roots ("together") and ("homeland"). The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation.Futuyma, D. J. 2009. ''Evolution'' (2nd edition). Sinauer Associates, Inc. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case, divergence is facilitated by the absence of gene flow. Parapatric speciation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where vegetation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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