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Oxygyrus Keraudrenii 2
''Oxygyrus keraudrenii'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. ''Oxygyrus keraudrenii'' is the only species in the genus ''Oxygyrus''. Description ''Oxygyrus keraudreni'' (along with '' Atlanta peronii'') attains the largest size (shell diameter to 10 mm) among the Atlantidae.Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. . Body coloration is light bluish-purple, with the color darkening with age. The larval shell is calcareous and displays a distinctive pattern of zigzag-shaped spiral ridges that are evenly spaced and cover the shell surface. The teleoconch is composed of conchiolin, a transparent cartilaginous material, and its surface lacks sculpture. With growth the teleoconch overgrows the protoconch and eventually surrounds it. A shell spire, as seen in all other atlantids, is lacking and the spire region is termed involute. The conchiolin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Neogene Period in the . The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygyrus Keraudrenii 3
''Oxygyrus keraudrenii'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. ''Oxygyrus keraudrenii'' is the only species in the genus ''Oxygyrus''. Description ''Oxygyrus keraudreni'' (along with '' Atlanta peronii'') attains the largest size (shell diameter to 10 mm) among the Atlantidae.Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. . Body coloration is light bluish-purple, with the color darkening with age. The larval shell is calcareous and displays a distinctive pattern of zigzag-shaped spiral ridges that are evenly spaced and cover the shell surface. The teleoconch is composed of conchiolin, a transparent cartilaginous material, and its surface lacks sculpture. With growth the teleoconch overgrows the protoconch and eventually surrounds it. A shell spire, as seen in all other atlantids, is lacking and the spire region is termed involute. The conchiolin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygyrus Keraudrenii 2
''Oxygyrus keraudrenii'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. ''Oxygyrus keraudrenii'' is the only species in the genus ''Oxygyrus''. Description ''Oxygyrus keraudreni'' (along with '' Atlanta peronii'') attains the largest size (shell diameter to 10 mm) among the Atlantidae.Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. . Body coloration is light bluish-purple, with the color darkening with age. The larval shell is calcareous and displays a distinctive pattern of zigzag-shaped spiral ridges that are evenly spaced and cover the shell surface. The teleoconch is composed of conchiolin, a transparent cartilaginous material, and its surface lacks sculpture. With growth the teleoconch overgrows the protoconch and eventually surrounds it. A shell spire, as seen in all other atlantids, is lacking and the spire region is termed involute. The conchiolin ... [...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] |
Spire (mollusc)
A spire is a part of the coiled shell of molluscs. The spire consists of all of the whorls except for the body whorl. Each spire whorl represents a rotation of 360°. A spire is part of the shell of a snail, a gastropod mollusc, a gastropod shell, and also the whorls of the shell in ammonites, which are fossil shelled cephalopods. In textbook illustrations of gastropod shells, the tradition (with a few exceptions) is to show most shells with the spire uppermost on the page. The spire, when it is not damaged or eroded, includes the protoconch (also called the nuclear whorls or the larval shell), and most of the subsequent teleoconch whorls (also called the postnuclear whorls), which gradually increase in area as they are formed. Thus the spire in most gastropods is pointed, the tip being known as the "apex". The word "spire" is used, in an analogy to a church spire or rock spire, a high, thin, pinnacle. The "spire angle" is the angle, as seen from the apex, at which a spire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoconch
A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called "nucleus". The protoconch may sometimes consist of several whorls, but when this is the case, the whorls show no growth lines. The whorls of the adult shell, which are formed after the protoconch, are known as the teleoconch. The teleoconch starts forming when the larval gastropod becomes a juvenile, and the protoconch may dissolve. Quite often there is a visible line of demarcation where the protoconch ends and the teleoconch begins, and there may be a noticeable change in sculpture, or a sudden appearance of sculpture at that point. In some gastropod groups (such as the Architectonicidae), the teleoconch whorls spiral in the opposite direction to the protoconch. In those cases, the shell is called heterostrophic. In species which ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sculpture (mollusc)
Sculpture is a feature of many of the shells of mollusks. It is three-dimensional ornamentation on the outer surface of the shell, as distinct from either the basic shape of the shell itself or the pattern of colouration, if any. Sculpture is a feature found in the shells of gastropods, bivalves, and scaphopods. The word "sculpture" is also applied to surface features of the aptychus of ammonites, and to the outer surface of some calcareous opercula of marine gastropods such as some species in the family Trochidae. Sculpture can be concave or convex, incised into the surface or raised from it. Sometimes the sculpture has microscopic detailing. The term "sculpture" refers only to the calcareous outer layer of shell, and does not include the proteinaceous periostracum, which is in some cases textured even when the underlying shell surface is smooth. In many taxa, there is no sculpture on the shell surface at all, apart from the presence of fine growth lines. The sculpture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conchiolin
Conchiolins (sometimes referred to as conchins) are complex proteins which are secreted by a mollusc's outer epithelium (the mantle). These proteins are part of a matrix of organic macromolecules, mainly proteins and polysaccharides, that assembled together form the microenvironment where crystals nucleate and grow. This organic matrix also holds and binds to the crystals of aragonite which give such shells their stiffness. The ions necessary to form calcium carbonate are also secreted by the mantle, but it is the tailored environment created by the organic matrix which causes aragonite (rather than calcite) crystals to nucleate, in much the same way that collagen nucleates hydroxyapatite crystals. Conchiolin serves as a relatively flexible, crack-deflecting matrix for the mineral aggregate particles; its strength and the strong bonding of perlucin can in some cases (such as in the formation of nacre) give the finished material an impressive level of toughness. As well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcareous
Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adjectival term applied to anatomical structures which are made primarily of calcium carbonate, in animals such as gastropods, i.e., snails, specifically about such structures as the operculum, the clausilium, and the love dart. The term also applies to the calcium carbonate tests of often more or less microscopic Foraminifera. Not all tests are calcareous; diatoms and radiolaria have siliceous tests. The molluscs are calcareous, as are calcareous sponges ( Porifera), that have spicules which are made of calcium carbonate. In botany ''Calcareous grassland'' is a form of grassland characteristic of soils containing much calcium carbonate from underlying chalk or limestone rock. In medicine The term is used in pathology, for example i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlanta Peronii
''Atlanta peronii'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae, as well as its typetaxon. Distribution This species is seen in South Korea, South and East China Sea region of Mainland China, as well as ocean regions around Taiwan. Description The maximum recorded shell length is 11 mm. Habitat holoplankton Holoplankton are organisms that are plankton, planktic (they live in the water column and cannot swim against a current) for their entire life cycle. Holoplankton can be contrasted with meroplankton, which are planktic organisms that spend part of ...ic, although habitat in sand-based shallow sea, the maximum recorded depth is 3338 m. References External links Atlantidae Gastropods described in 1817 {{Atlantidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
