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Margarella Antarctica
''Margarella antarctica'' is a species of sea snail, a marine gastropod mollusk in the family (biology), family Calliostomatidae, the top snails. Distribution This marine species occurs off the South Orkney Islands, the South Shetland Islands, the Antarctic Peninsula, and the Bellingshausen Sea. Description It is orange-yellow, with two pairs of cephalic tentacles with large black eyes. The shell is small, and wider than it is high.Bouchet, P. (2010). ''Margarella whiteana'' Linse, 2002. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=197259 on 2011-03-17 The orbicular, deeply umbilicated shell has an obtuse-conical shape. It contains four convex Whorl (mollusc), whorls, the last of which is adorned only by growth lines. The oblique Aperture (mollusc), aperture is sub-circular and pearly inside. In, adults its edges are joined by a callus . The Operculum (gastropod), operculum is polygyrous spiral. The color of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Édouard Lamy
Édouard is both a French given name and a surname, equivalent to Edward in English. Notable people with the name include: * Édouard Balladur (born 1929), French politician * Édouard Boubat (1923–1999), French photographer * Édouard Colonne (1838–1910), French conductor * Édouard Daladier (1884–1970), French prime minister at the start of World War II * Edouard Drumont (1844–1917), French anti-semitic journalist * Édouard Dujardin (1861–1949), French writer * Édouard Gagnon (1918–2007), French Canadian cardinal * Édouard Herriot (1872–1957), French prime minister, three times, and mayor of Lyon from 1905 to 1957 * Edouard F. Henriques, Make-up artist * Édouard Lalo (1823–1892), French composer * Édouard Lockroy (1838–1913), French politician * Édouard Louis (born 1992), French Writer * Édouard Lucas (1842–1891), French mathematician * Édouard Mathé (1886–1934), French silent film actor * Édouard Manet (1832–1883), French impressionist pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Peninsula
The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San MartĂn in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica. The Antarctic Peninsula is part of the larger peninsula of West Antarctica, protruding from a line between Cape Adams (Weddell Sea) and a point on the mainland south of the Eklund Islands. Beneath the ice sheet that covers it, the Antarctic Peninsula consists of a string of bedrock islands; these are separated by deep channels whose bottoms lie at depths considerably below current sea level. They are joined by a grounded ice sheet. Tierra del Fuego, the southernmost tip of South America, is about away across the Drake Passage. The Antarctic Peninsula is in area and 80% ice-covered. The marine ecosystem around the western continental shelf of the Antarctic Peninsula (WAP) has been subjected to rapid climate change. Over the past 50 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
The gastropod shell is part of the body of a Gastropoda, gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the Aperture (mollusc), aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as c ... [...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] |
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc. The term ''aperture'' is used for the main opening in gastropod shells, scaphopod shells, and also for ''Nautilus'' and ammonite shells. The word is not used to describe bivalve shells, where a natural opening between the two shell valves in the closed position is usually called a ''gape''. Scaphopod shells are tubular, and thus they have two openings: a main anterior aperture and a smaller posterior aperture. As well as the aperture, some gastropod shells have additional openings in their shells for respiration; this is the case in some Fissurellidae (keyhole limpets) where the central smaller opening at the apex of the shell is called an orifice, and in the Haliotidae (abalones) where the row of respiratory openings in the shell are also called orifices. In gastropods In some prosobranch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in numerous gastropods, but it is also found in shelled cephalopods including ''Nautilus'', ''Spirula'' and the large extinct subclass of cephalopods known as the ammonites. A spiral shell can be visualized as consisting of a long conical tube, the growth of which is coiled into an overall helical or planispiral shape, for reasons of both strength and compactness. The number of whorls which exist in an adult shell of a particular species depends on mathematical factors in the geometric growth, as described in D'Arcy Wentworth Thompson's classic 1917 book ''On Growth and Form'', and by David Raup. The main factor is how rapidly the conical tube expands (or flares-out) over time. When the rate of expansion is low, such that each subsequent whorl is not that much wider than the previous one, then the adult shell has numerous whorls. When the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bellingshausen Sea
The Bellingshausen Sea is an area along the west side of the Antarctic Peninsula between 57°18'W and 102°20'W, west of Alexander Island, east of Cape Flying Fish on Thurston Island, and south of Peter I Island (there the southern ''Vostokkysten''). In the south are, from west to east, Eights Coast, Bryan Coast and English Coast (west part) of West Antarctica. To the west of Cape Flying Fish it joins the Amundsen Sea. Bellingshausen Sea has an area of and reaches a maximum depth of . It contains the undersea plain Bellingshausen Plain. It takes its name from Admiral Thaddeus Bellingshausen, who explored in the area in 1821. In the late Pliocene Epoch, about 2.15 million years ago, the Eltanin asteroid (about 1-4 km in diameter) impacted at the edge of the Bellingshausen sea (at the South Pacific Ocean South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. Etymology The word ''south' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Shetland Islands
The South Shetland Islands are a group of Antarctic islands with a total area of . They lie about north of the Antarctic Peninsula, and between southwest of the nearest point of the South Orkney Islands. By the Antarctic Treaty of 1959, the islands' sovereignty is neither recognized nor disputed by the signatories and they are free for use by any signatory for non-military purposes. The islands have been claimed by the United Kingdom since 1908 and as part of the British Antarctic Territory since 1962. They are also claimed by the governments of Chile (since 1940, as part of the AntĂ¡rtica Chilena province) and Argentina (since 1943, as part of Argentine Antarctica, Tierra del Fuego Province). Several countries maintain research stations on the islands. Most of them are situated on King George Island, benefitting from the airfield of the Chilean base Eduardo Frei. There are sixteen research stations in different parts of the islands, with Chilean stations being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basionym
In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botany and zoology. In zoology, alternate terms such as original combination or protonym are sometimes used instead. Bacteriology uses a similar term, basonym, spelled without an ''i''. Although "basionym" and "protonym" are often used interchangeably, they have slightly different technical definitions. A basionym is the ''correct'' spelling of the original name (according to the applicable nomenclature rules), while a protonym is the ''original'' spelling of the original name. These are typically the same, but in rare cases may differ. Use in botany The term "basionym" is used in botany only for the circumstances where a previous name exists with a useful description, and the '' International Code of Nomenclature for algae, fungi, and plants' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Orkney Islands
The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula''Antarctica: Secrets of the Southern Continent'' p. 122 David McGonigal, 2009 and south-west of . They have a total area of about . The islands are claimed both by Britain (as part of the since 1962, previously as a [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calliostomatidae
Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.Gofas, S. (2013). Calliostomatidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=382180 on 2013-07-08 Description The Calliostomatidae are unusually diverse. They are characterized by a stepped spire and a pointy aperture. They may possess or lack an umbilicus. The collumella is sometimes thicker, partially covering the aperture. The spiral whorls can differ between narrow and robust. They inhabit a wide range of ocean habitats, from the intertidal zone to mid- bathyal depths. Taxonomy This taxon was long considered to be a subfamily of the Trochidae. 2005 taxonomy This family consists of two following subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005): * subfamily Calliostomatinae Thiele 1924 (1847) ** tribe Calliostomatini Thiele 1924 (1847) - synonym: Ziziphininae G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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