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Xiphophorus Nigrensis
''Xiphophorus nigrensis'', the Panuco swordtail, is a species of fish in the family Poeciliidae that is endemic to a small part of the Pánuco River basin in Mexico. Taxonomy Being a small swordtail, ''Xiphophorus nigrensis'' was originally considered a subspecies of '' X. pygmaeus''. Today it is recognized, along with '' X. multilineatus'', as the closest related species to ''X. pygmaeus''. The three species form a clade within the larger clade of northern swordtails. The similarity of the large males of ''X. nigrensis'' to the small males of '' X. cortezi'', another northern swordtail, points to a close evolutionary relationship between these two species. Description The body of ''Xiphophorus nigrensis'' is larger and deeper than that of ''X. pygmaeus''. The males possess on their caudal fin a moderately to well-developed sword set off by a black line, from which the specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Donn Eric Rosen
Donn Eric Rosen (1929-1986) was a member of the staff of the American Museum of Natural History. He was a Distinguished Fellow of the American Society of Ichthyologists and Herpetologists. Family Born to immigrants Irwin Rosen (b. 1885) and Anita Gerber Rosen (b. 1906), Rosen has an older brother : Charles Welles. Both his parents were born in Russia. Irwin came to the United States in 1889 and had a career in architecture. Anita arrived in the United States prior to 1920. Works Rosen has written over twenty eight scientific papers. Rosen has described twenty three species. Selected publications *Rosen, Donn Eric, P. Humphry Greenwood 1970. Origin of the Weberian Apparatus and the Relationships of the Ostariophysan and Gonorynchiform Fishes, American Museum Novitates, American Museum of Natural History,New York, New York, USA, 2428 *Rosen, Donn Eric, Bailey, Reeve M. The Poeciliid Fishes (Cyprinodontiformes), Their Structure, Zoogeography, and Systematics. Bulletin of the A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus Cortezi
''Xiphophorus cortezi'', the delicate swordtail, is a species of poeciliid fish from Mexico. Named after the Spanish ''conquistador'' Hernán Cortés, ''Xiphophorus cortezi'' was originally described in 1960 by Donn Eric Rosen as a subspecies of '' X. montezumae''. It was well known in literature prior to the formal scientific description. The smaller males of ''X. cortezi'' are similar to the larger males of '' X. nigrensis'', pointing to a close evolutionary relationship with this species too. Adult size is variable and averages about 30 mm in standard length. The color of the male, especially the midlateral stripe, depends on the excitement of the fish and background shade of its environment. Some specimens kept in the laboratory for years have shown such silvery coloring that black markings became absent. Different patterns of black spots on the tail exist. ''Xiphophorus cortezi'' is found in the upper Rio Panuco system in northeastern Mexico. Two congeners, '' X. pygmaeus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Fish Of Mexico
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Fish Of Mexico
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus
''Xiphophorus'' is a genus of euryhaline and freshwater fishes in the family Poeciliidae of order Cyprinodontiformes, native to Mexico and northern Central America. The many ''Xiphophorus'' species are all known as platyfish (or platies) and swordtails. Platyfish formerly were classified in another genus, ''Platypoecilia'', which is now obsolete. The type species is ''X. hellerii,'' the green swordtail. Like most other new world Poeciliids, platies and swordtails are live-bearers that use internal fertilization and give birth to live young instead of laying eggs like the bulk of the world's fishes. The name ''Xiphophorus'' derives from the Greek words ξίφος (dagger) and φόρος (bearer), referring to the gonopodium on the males. All are relatively small fishes, which reach a maximum length of depending on the exact species involved. Distribution and conservation status The various ''Xiphophorus'' species range from the southern Rio Grande basin in Mexico, through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio Choy
Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a town in the state of Santa Catarina, Brazil Mexico * Río Bec, a Mayan archaeological site in Mexico * Río Bravo, Tamaulipas, a city in Mexico United States * Rio, a location in Deerpark, New York, US * Rio, Florida, a census-designated place in Martin County, US * Rio, Georgia, an unincorporated community in Spalding County, US * Rio, Illinois, a village in Knox County, US * Rio, Virginia, a community in Albemarle County, US * Rio, West Virginia, a village in Hampshire County, US * Rio, Wisconsin, a village in Columbia County, US * El Río, Las Piedras, Puerto Rico, a barrio * Río Arriba, Añasco, Puerto Rico, a barrio * Río Arriba, Arecibo, Puerto Rico, a barrio * Río Arriba, Fajardo, Puerto Rico, a barrio * Río Arriba, Vega Baja, Pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravid Spot
Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after egg-sperm union. Although the term often refers to placental mammals, it has also been used in the titles of many international, peer-reviewed, scientific articles on fish, e.g.. Consistent with this definition, there are several modes of reproduction in fish, providing different amounts of parental care. In ovoviviparity, there is internal fertilization and the young are born live but there is no placental connection or significant trophic (feeding) interaction; the mother's body maintains gas exchange but the unborn young are nourished by egg yolk. There are two types of viviparity in fish. In histotrophic viviparity, the zygotes develop in the female's oviducts, but she provides no direct nutrition; the embryos survive by eating her eggs or their unborn siblings. In hemotrophic viviparity, the zygotes are retained within the female and are provided with nutrients by her, oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Epithet
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name (which may be shortened to just "binomial"), a binomen, name or a scientific name; more informally it is also historically called a Latin name. The first part of the name – the '' generic name'' – identifies the genus to which the species belongs, whereas the second part – the specific name or specific epithet – distinguishes the species within the genus. For example, modern humans belong to the genus ''Homo'' and within this genus to the species ''Homo sapiens''. ''Tyrannosaurus rex'' is likely the most widely known binomial. The ''formal'' introduction of this system of naming species is credit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...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] |
Xiphophorus Multilineatus
''Xiphophorus multilineatus'' is a fish in the family Poeciliidae. It is endemic to a small part of the Pánuco River The Pánuco River ( es, Río Pánuco, ), also known as the ''Río de Canoas'', is a river in Mexico fed by several tributaries including the Moctezuma River and emptying into the Gulf of Mexico. The river is approximately long and passes throug ... basin in Mexican. References multilineatus Taxa named by Mary Rauchenberger Taxa named by Klaus D. Kallman Taxa named by Donald Charles Morizot Fish described in 1990 {{Cyprinodontiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus Pygmaeus
''Xiphophorus pygmaeus'', the pygmy swordtail, is a poeciliid fish from northeastern Mexico. It is the smallest of the swordtails. The male's sword is barely visible and the species is often called the swordless swordtail. It is sometimes kept in home aquaria, but is a rather delicate species. Taxonomy and evolution ''Xiphophorus pygmaeus'' is the smallest member of the genus ''Xiphophorus''. It is most closely related to '' X. multilineatus'' and '' X. nigrensis'', and males in particular look similar to the small males of the latter two species. The three species form a clade within the larger clade of northern swordtails. ''X. pygmaeus'' lost large-sized males and male traits associated with larger size: courtship behavior, body depth, and well-developed swords. Large size eventually reappeared in ''X. pygmaeus'' but the normally accompanying traits did not. Description Females grow to , while males attain . The male's sword is only 1-2 mm long. The species was originally thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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