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Protatlanta Rotundata
''Protatlanta rotundata'' is an extinct species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. Description The width of the shell can reach up to 10 mm. In the largest specimen there are almost two teleoconch whorls that initially attach very high onto the protoconch, with the result that the larval shell seems to be embedded rather obliquely within the younger whorls. The diameter of the teleoconch increases rapidly, the result being a shell that strongly resembles '' Planorbarius'' (but, of course, dextral). The surface of these younger whorls bears flexuous growth lines, and a dense and very fine, somewhat irregular spiral striation, only visible where light reflects on the shell. On the body whorl a distinct peripheral belt is present on which the growth lines are strongly bent backward, indicating a deep sinus in the apertural margin. The larval shell is globular, about as wide as high and has approximately five whorls which attac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 their life cycle in the benthic zone. Examples of holoplankton include some diatoms, radiolarians, some dinoflagellates, foraminifera, amphipods, krill, copepods, and salps, as well as some gastropod mollusk species. Holoplankton dwell in the pelagic zone as opposed to the benthic zone. Holoplankton include both phytoplankton and zooplankton and vary in size. The most common plankton are protists. Reproduction Holoplankton have unique traits that make reproduction in the water column possible. Both Sexual reproduction, sexual and Asexual reproduction, asexual reproduction are used depending on the type of plankton. Some invertebrate holoplankton release sperm into the water column which are then taken up by the females for fertilization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protatlanta Souleyeti
''Protatlanta souleyeti'' is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. ''Protatlanta souleyeti'' is the type species on the genus ''Protatlanta''. It is considered to be the only Recent species on the genus. The specific name ''souleyeti'' is in honor of French malacologist Louis François Auguste Souleyet. Description The maximum recorded shell length is 2 mm.Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. . Some of the fossil specimens preserve a pinkish colour of the larval shells. The protoconch is naticoid in shape and has approximately 3¼ whorls. Most specimens have two thin spirals above the periphery, visible in apical view, and a third such spiral below the periphery, which separates the base of the protoconch and becomes covered by subsequent whorls. The described ornament can be fairly constant, but some specimens were found in which thes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suture (gastropod)
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements. Sutures are found in the skeletons or exoskeletons of a wide range of animals, in both invertebrates and vertebrates. Sutures are found in animals with hard parts from the Cambrian period to the present day. Sutures were and are formed by several different methods, and they exist between hard parts that are made from several different materials. Vertebrate skeletons The skeletons of vertebrate animals (fish, amphibians, reptiles, birds, and mammals) are made of bone, in which the main rigid ingredient is calcium phosphate. Cranial sutures The skulls of most vertebrates consist of sets of bony plates held together by cranial sutures. These sutures are held together mainly by Sharpey's fibers which grow from each bone into the adjoining one. Sutures in the ankles of land vertebrates In the type of crurotarsal ankle which is found i ... [...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] |
Body Whorl
The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the body whorl, or last whorl, is the most recently formed and largest whorl (or revolution) of a spiral or helical shell, terminating in the aperture. It is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs greatly according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is very high, the aperture and the body whorl are large, and the shell tends to be low spired. The shell of the abalone is a good example of this kind of shell. The opposite tendency can sometimes create a high spire with very little whorl increase per revolution. In these instances, e.g. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planorbarius
''Planorbarius'' is a genus of air-breathing freshwater snails, Aquatic animal, aquatic pulmonate gastropod mollusks in the family (biology), family Planorbidae, the sheep, ram's horn snails, or planorbids, which all have sinistral or left-coiling shells.Neubauer, Thomas A.; Bouchet, P. (2014). Planorbarius Duméril, 1805. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=818481 on 2014-11-19 Species Species within this genus include: * † ''Planorbarius barettii'' (Sacco, 1886) * † ''Planorbarius borellii'' (Brusina, 1892) * ''Planorbarius corneus'' (Carl Linnaeus, Linnaeus, 1758)Linnaeus C. (1758). ''Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis''. 10th edition. - Vermes. Testacea: 700-781. Holmiae. (Salvius). * † ''Planorbarius cornu (''Brongniart, 1810) * † ''Planorbarius cornucopia'' (Baily, 1858) * † ''Planorbarius cr ... [...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] |
Teleoconch
The gastropod shell is part of the body of a 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, 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. The calcareous central layer, tracum, is typically made of calcium carbonate precipitated into an organic matrix known as conchiolin. The outermost layer is the periostra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protatlanta Rotundata 3
''Atlanta'' is a genus of pelagic marine gastropod molluscs in the family Atlantidae. Species Species in the genus ''Atlanta'' include: * ''Protatlanta souleyeti'' (Smith, 1888) - type species and the only Recent species in the genus ''Protatlanta'' * ''Protatlanta mediterranea'' Issel, 1915 - recent, sometimes is this considered as separate speciesStoch F. (ed.Atlantidae in: CHECKLIST OF THE SPECIES OF THE ITALIAN FAUNA. On-line version 2.0. http://www.faunaitalia.it/checklist/ Last update: December 3, 2003, accessed 20 August 2010. * † ''Protatlanta rotundata ''Protatlanta rotundata'' is an extinct species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. Description The width of the shell can reach up to 10 mm. In the largest specimen there are almost two te ...'' (Gabb, 1873) References {{Taxonbar, from=Q7251191 Atlantidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protatlanta Rotundata 2
''Atlanta'' is a genus of pelagic marine gastropod molluscs in the family Atlantidae. Species Species in the genus ''Atlanta'' include: * ''Protatlanta souleyeti'' (Smith, 1888) - type species and the only Recent species in the genus ''Protatlanta'' * ''Protatlanta mediterranea'' Issel, 1915 - recent, sometimes is this considered as separate speciesStoch F. (ed.Atlantidae in: CHECKLIST OF THE SPECIES OF THE ITALIAN FAUNA. On-line version 2.0. http://www.faunaitalia.it/checklist/ Last update: December 3, 2003, accessed 20 August 2010. * † ''Protatlanta rotundata ''Protatlanta rotundata'' is an extinct species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae. Description The width of the shell can reach up to 10 mm. In the largest specimen there are almost two te ...'' (Gabb, 1873) References {{Taxonbar, from=Q7251191 Atlantidae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family ( la, familia, plural ') 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". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
