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Margarites Groenlandicus
''Margarites groenlandicus'', common name the Greenland margarite or wavy top shell, is a species of sea snail, a marine gastropod mollusk in the family Margaritidae. There are two subspecies : * ''Margarites groenlandicus groenlandicus'' (Gmelin, 1791) * ''Margarites groenlandicus kurilensis'' Golikov & Gulbin, 1978 * ''Margarites groenlandicus umbilicalis'' Broderip & Sowerby, 1829 (synonym : ''Margarites umbilicalis'' Broderip & Sowerby, 1829) Description The wavy top shell is thin-shelled and rather small with a maximum length of 1.9 cm (¾ inch) and a compressed spire. The color of the glossy shell is cream to brown. It contains 4-5 whorls, with the body whorl the largest. The sutures are wavy. The shell is smooth or with about 12 smooth spiral ridges. The broad umbilicus is funnel-shaped. The nacreous aperture is oval with the long axis inclined to the left. It is also prosocline, i.e. with the growth lines leaning forward (adapically) with respect to the direction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Friedrich Gmelin
Johann Friedrich Gmelin (8 August 1748 – 1 November 1804) was a German natural history, naturalist, chemist, botanist, entomologist, herpetologist, and malacologist. Education Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen. He studied medicine under his father at University of Tübingen and graduated with a Master's degree in 1768, with a thesis entitled: ', defended under the presidency of Ferdinand Christoph Oetinger, whom he thanks with the words '. Career In 1769, Gmelin became an adjunct professor of medicine at University of Tübingen. In 1773, he became professor of philosophy and adjunct professor of medicine at University of Göttingen. He was promoted to full professor of medicine and professor of chemistry, botany, and mineralogy in 1778. He died in 1804 in Göttingen and is buried there in the Albanifriedhof, Albani cemetery with his wife Rosine Louise Gmelin (1755–1828, née Schott). Johann Friedrich Gm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbilicus (mollusc)
The umbilicus of a coiled mollusc shell is the axially aligned, hollow cone-shaped space within its whorl (mollusc), whorls. The term ''umbilicus'' is often used in descriptions of gastropoda, gastropod shells, i.e. it is a feature present on the ventral (or under) side of many (but not all) snail shells, including some species of sea snails, land snails, and freshwater snails. The word is also applied to the depressed central area on the planispiral coiled shells of ''Nautilus'' species and fossil ammonites. (These are not gastropods, but shelled cephalopods.) In gastropods The spirally coiled whorls of gastropod shells frequently connect to each other by their inner sides, during the natural course of its formation. This results in a more or less solid central axial pillar, known as the columella (mollusc), columella. The more intimate the contact between the concave side of the whorls is, the more solid the columella becomes. On the other hand, if this connection is less inten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margarites
''Margarites'' is a genus of sea snails, marine gastropod mollusks in the family Margaritidae. This genus belonged previously to the subfamily Margaritinae in the family Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie .... Description This genus consists of small species of variable size between 3 mm and 15 mm. The Alaskan specimens of '' Margarites costalis'' reach almost 25 mm in diameter. Their flat shell has a turbiniform shape with convex whorls and a typical iridescent lustre. Species Species within the genus ''Margarites'' include: * '' Margarites albolineatus'' (E. A. Smith, 1899) * '' Margarites angulatus'' Galkin, 1955 * '' Margarites argentatus'' (Gould, 1841) * '' Margarites atlantoides'' (Quinn, 1992) * '' Margarites avachensis'' Galkin, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bathyal Zone
The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The bathypelagic is also known as the midnight zone because of the lack of sunlight; this feature does not allow for photosynthesis-driven primary production, preventing growth of phytoplankton or aquatic plants. Although larger by volume than the photic zone, human knowledge of the bathypelagic zone remains limited by ability to explore the deep ocean. Physical characteristics The bathypelagic zone is characterized by a nearly constant temperature of approximately and a salinity range of 33-35 g/kg. This region has little to no light because sunlight does not reach this deep in the ocean and bioluminescence is limited. The hydrostatic pressure in this zone ranges from 100-400 atmospheres (atm) due to the increase of 1 atm for every 10 m depth. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodite
A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many taxonomic groups of animals, primarily invertebrates, are hermaphrodites, capable of producing viable gametes of both sexes. In the great majority of tunicates, mollusks, and earthworms, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. Hermaphroditism is also found in some fish species, but is rare in other vertebrate groups. Most hermaphroditic species exhibit some degree of self-fertilization. The distribution of self-fertilization rates among animals is similar to that of plants, suggesting that similar pressures are operating to direct the evolution of selfing in animals and plants. A rough estimate of the number of hermaphroditic animal species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lip (gastropod)
In the shell of gastropod mollusks (a snail shell), the lip is the free margin of the peristome (synonym: peritreme) or aperture (mollusc), aperture (the opening) of the gastropod shell. In dextral (right-handed) shells (most snail shells are right-handed), the right side or outer side of the aperture is known as the outer lip (''labrum''). The left side of the aperture is known as the inner lip or columellar lip (''labium'') if there is a pronounced lip there. In those species where there is no pronounced lip, the part of the body whorl that adjoins the aperture is known as the parietal wall. The outer lip is usually thin and sharp in immature shells, and in some adults (e.g. the land snails ''Helicella'' and ''Bulimulus''). However, in some other land snails and in many marine species the outer lip is ''thickened'' (also called ''callused''), or ''reflected'' (turned outwards). In some other marine species it is curled inwards (''inflected''), as in the cowries such as ''Cypraea ... [...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 (bivalve), 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 (mollusc), apex of the shell is called an orifice, and in the Haliotidae (abalone) where the row of respiratory openings in the shell are also called orifices. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacre
Nacre ( , ), also known as mother-of-pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is found in some of the most ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as ''flame structure'' as is found in conch pearls. The outer layer of cultured pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae. Physical characteristics Structure and appearance Nacre is composed of hexagonal platelets, called tablets, of aragonite (a form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral or whorled 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 Cone (geometry), conical tube, the growth of which is coiled into an overall Helix, 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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrasted with the scientific name for the same organism, which is often based in Latin. A common name is sometimes frequently used, but that is not always the case. In chemistry, IUPAC defines a common name as one that, although it unambiguously defines a chemical, does not follow the current systematic naming convention, such as acetone, systematically 2-propanone, while a vernacular name describes one used in a lab, trade or industry that does not unambiguously describe a single chemical, such as copper sulfate, which may refer to either copper(I) sulfate or copper(II) sulfate. Sometimes common names are created by authorities on one particular subject, in an attempt to make it possible for members of the general public (including s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaritidae
Margaritidae is a family of small sea snails, marine gastropod mollusks in the superfamily Trochoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Margaritidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=714634 on 3 JUly 2013 Margaritinae Thiele, 1924, originally a subfamily in Trochidae was moved to Turbinidae Turbinidae, the turban snails, are a family of small to large marine gastropod molluscs in the superfamily Trochoidea.Bouchet, P. (2014). Turbinidae Rafinesque, 1815. Accessed through: World Register of Marine Species at http://www.marinespecie ... following Williams et al. 2007. It has been elevated to the rank of family Margaritidae. This family has no subfamilies. Genera Genera within the family Margaritidae include: * '' Anomphalogaza'' Hickman, 2012 * '' Antimargarita'' Powell, 1951 * '' Callogaza'' Dall, 1881 * '' Gaza'' Watson, 1879 * '' Marga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
