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Goniobasis Drakei
''Pleurocera'' is a genus of freshwater snails with an operculum, aquatic gastropod mollusks in the family Pleuroceridae.Neubauer, Thomas A. (2014). Pleurocera Rafinesque, 1818. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=820483 on 2014-11-25 ''Pleurocera'' is the type genus of that family. Distribution All members of the genus ''Pleurocera'' are native to eastern North America. Description All of the species in this genus have thick-walled high- spired shells, and some attain a length of over 4 cm. The shape of the shell is elongate-conic or cylindrical. The sculpture of the shell is often carinate or costate. The shell of larger species sometimes develops sculpturing and a small siphonal canal or siphonal notch at the base of the aperture. Opercula are paucispiral and corneous, but may be vestigial in some species, not completely closing the aperture. The soft parts of the animal usually have a ... [...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] |
Siphonal Notch
A siphonal notch is a feature of the shell anatomy in some sea snails, marine gastropod mollusks. In these particular groups of sea snails the animal has a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. This siphonal opening also serves for the exit of the water that has entered by the branchial opening. The siphonal notch is a noticeable notch situated at the most posterior part of the aperture of the shell, through which the siphon is extended when the animal is active. The notch at the posterior end of the aperture is also called the anal notch, anal sinus, anal canal or posterior canal. Instead of a simple siphonal notch, some gastropods have an elongated siphonal canal, a hard shell tube which extends out from the anterior edge of the aperture. See also * Siphonal canal * Stromboid notch The stromboid notch is an anatomical feature whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corpulent Hornsnail
The corpulent hornsnail, scientific name ''Pleurocera corpulenta'', is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Pleuroceridae. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie .... References Molluscs of the United States Pleuroceridae Taxonomy articles created by Polbot {{Pleuroceridae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurocera Catenaria
''Pleurocera'' is a genus of freshwater snails with an operculum, aquatic gastropod mollusks in the family Pleuroceridae.Neubauer, Thomas A. (2014). Pleurocera Rafinesque, 1818. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=820483 on 2014-11-25 ''Pleurocera'' is the type genus of that family. Distribution All members of the genus ''Pleurocera'' are native to eastern North America. Description All of the species in this genus have thick-walled high- spired shells, and some attain a length of over 4 cm. The shape of the shell is elongate-conic or cylindrical. The sculpture of the shell is often carinate or costate. The shell of larger species sometimes develops sculpturing and a small siphonal canal or siphonal notch at the base of the aperture. Opercula are paucispiral and corneous, but may be vestigial in some species, not completely closing the aperture. The soft parts of the animal usually have a gray ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Hornsnail
The spiral hornsnail, scientific name ''Pleurocera brumbyi'', is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Pleuroceridae. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie .... References Molluscs of the United States Pleuroceridae Taxonomy articles created by Polbot {{Pleuroceridae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ringed Hornsnail
The ringed hornsnail, scientific name ''Pleurocera annulifera'', is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Pleuroceridae. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie .... References Molluscs of the United States Pleuroceridae Taxonomy articles created by Polbot {{Pleuroceridae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rugged Hornsnail
The rugged hornsnail, scientific name ''Pleurocera alveare'', is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Pleuroceridae. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie .... References Molluscs of the United States Pleuroceridae Taxonomy articles created by Polbot {{Pleuroceridae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Of Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries. Organization The ICZN is governed by the "Constitution of the ICZN", which is usually published together with the ICZN Code. Members are elected by the Section of Zoological Nomenclature, established by the International Union of Biological Sciences (IUBS). The regular term of service of a member of the Commission is six years. Members can be re-elected up to a total of three full six-year terms in a row. After 18 continuous years of elected service, a break of at least three years is prescribed before the member can stand again for election. Activities Since 2014, the work of the Commission is supported by a small secretariat based at the National University of Singapore, in Singapore. Previously, the secretariat was based in London and fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen(s). Article 67.1 A similar concept is used for suprageneric groups and called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen (or, rarely, an illustration) which is also the type of a species name. The species name that has that type can also be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, and some higher-rank names based on genus names, have such types. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seminal Receptacle
Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized. The site of storage is variable among different animal taxa and ranges from structures that appear to function solely for sperm retention, such as insect spermatheca and bird sperm storage tubules (bird anatomy), to more general regions of the reproductive tract enriched with receptors to which sperm associate before fertilization, such as the caudal portion of the cow oviduct containing sperm-associating annexins. Female sperm storage is an integral stage in the reproductive process for many animals with internal fertilization. It has several documented biological functions including: * Supporting the sperm by: a.) enabling sperm to undergo biochemical transitions, called capacitation and motility hyperactivation, in which th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juga
''Juga'' is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Semisulcospiridae. These snails are native to the rivers of the northwestern United States and adjacent British Columbia. Several species are endemic to isolated large springs in the American Great Basin.Strong, E. E., & Whelan, N. V. (2019). Assessing the diversity of western North American Juga (Semisulcospiridae, Gastropoda). Molecular Phylogenetics and Evolution, 136, 87-103. The most abundant and widespread species, ''Juga plicifera'', attains a height of up to 35 mm. It is sculpted with fine spiral ridges and variably developed ribs that frequently disappear in parts of the shell made as the animal matures. Species The following species and subspecies are recognized: Subgenus ''Juga'' s.s. * '' Juga hemphilli'' (J. Henderson, 1935) ** ''Juga hemphilli dallesensis'' (J. Henderson, 1935) ** ''Juga hemphilli maupinensis'' (J. Henderson, 1935) * '' Jug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vestigiality
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species. Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ; and the hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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