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Amnicola Missouriensis
''Amnicola missouriensis'', common name the Missouri amnicola, is a species of freshwater snail, an aquatic gastropod mollusk in the family Amnicolidae. Shell description The shell is minute, imperforate, obliquely ovate, light brown. The surface of the shell is smooth except for slight growth-lines. The shell is composed of 3½ very convex whorls separated by unusually deep sutures. The apex is obtuse and often eroded. The last whorl is shortly deflexed in front in adult specimens. The aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ... is rotund-ovate, being slightly narrowed above, but not angular there. The aperture is not modified in form by the preceding whorl. The aperture is moderately oblique. The peristome is continuous, not closely appressed at the upper l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Augustus Pilsbry
Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a century. For much of his career, his authority with respect to the classification of certain substantial groups of organisms was unchallenged: barnacles, chitons, North American terrestrial molluscs, terrestrial mollusks, and others. Biography Pilsbry (frequently misspelled ''Pilsbury'') spent his childhood and youth in Iowa. He was called "Harry" Pilsbry then, and developed an early fascination with the limited variety of mollusks he was able to find. He attended the University of Iowa, and received the Bachelor of Science degree there in 1882, but did not immediately find employment in his field of interest. Instead, Henry Pilsbry worked for publishing firms and newspapers for the next several years, but devoted most of his spare time to the ... [...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] |
Carter County, Missouri
Carter County is a county in the Ozarks of Missouri. At the 2020 census, it had a population of 5,202. The largest city and county seat is Van Buren. The county was officially organized on March 10, 1859, and is named after Zimri A. Carter, a pioneer settler who came to Missouri from South Carolina in 1812. History Creation When the Missouri legislature created Carter County on March 10, 1859, it named the county after Zimri A. Carter. Zimri A. Carter (1794–1872) was born in South Carolina. In 1807, at the age of 13, he came to Missouri with his parents. The Carter family initially settled in what is now Warren County. Shortly after his arrival in Missouri Carter joined up with a party of traders traveling the Missouri and Mississippi rivers in flat boats, and was away for a number of years. In his absence his father Benjamin Carter traded a horse and a cow for a large tract of land in what was then Wayne County, about eight miles southeast of where the town of Van Buren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bythinella Aldrichi
''Bythinella'' is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Bythinellidae (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). These gonochoristic snails are small animals, with a shell length of about 2–4 mm.Bichain ''et al.'' (2007) ''Amnicola'' is a close relative, containing North American snails with essentially similar appearance and ecology. The scientific name means "small ''Bithynia''"; the latter snail genus is somewhat similar at a casual glance (though much larger) but not at all closely related among the Rissooidea. Distribution The present genus occurs in springs, and sometimes caves or groundwater, from Catalonia across central Europe to the Aegean Region of Turkey. In and around France a particularly high diversity of these snails is found. Due to the limited range and special and easily destroyed habitat, these snails are liable to become endangered species. Species More tha ... [...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] |
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] |
Apex (mollusc)
In anatomy, an apex (adjectival form: apical) is part of the shell of a mollusk. The apex is the pointed tip (the oldest part) of the shell of a gastropod, scaphopod, or cephalopod. The apex is used in end-blown conches. Gastropods The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod. The apex is the first-formed, and therefore the oldest, part of the shell. To be more precise, the apex would usually be where the tip of the embryonic shell or protoconch is situated, if that is still present in the adult shell (often it is lost or eroded away). Coiled gastropod shells The phrase apical whorls, or protoconch, means the whorls that constitute the embryonic shell at the apex of the shell, especially when this is clearly distinguishable from the later whorls of the shell, otherwise known as the teleoconch. Comparison of the apical part and the whole shell of ''Otukaia kiheiziebisu'': File:Calliostoma kiheiziebisu apex.png File:Calliostoma k ... [...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] |
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] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amnicolidae
Amnicolidae is a family of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the superfamily Rissooidea. This family is in the clade Littorinimorpha (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). This family was previously considered to be a subfamily of Hydrobiidae. Subfamilies The family Amnicolidae consists of 3 subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005): *Subfamily Amnicolinae Tryon, 1863, synonymised with: **Tribe Erhaiini Davis & Kuo, 1985 **Subfamily Lyogyrinae Pilsbry, 1916 **Subfamily Parabythinellinae Radoman, 1976 **Tribe Pseudobythinellini Davis & Chen, 1992 *Subfamily Baicaliinae P. Fisher, 1885, synonymised with: **Subfamily Liobaicaliinae B. Dybowski & Grochmalicki, 1913 **Subfamily Turribaicaliinae B. Dybowski & Grochmalicki, 1917 Genera *Subfamily Amnicolinae Tryon, 1863 **''Akiyoshia'' Kuroda & Habe, 1954Davis G. M. & Rao S. (1997). "Discovery of ''Erhai ... [...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] |
