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Monterrey Platyfish
The Monterrey platyfish (''Xiphophorus couchianus'') is a species of freshwater fish in family Poecilidae. A live-bearer, it was native to a very small section of the San Juan River system (itself part of the Rio Grande basin) in the vicinity of the city of Monterrey, Mexico. The specific name refers to the American soldier and naturalist Darius N. Couch (1822–1897) who collected the type on a self financed expedition to Mexico. Appearance The Monterrey platyfish is a dull-colored fish, appearing not unlike a female guppy. Another form, sometimes referred to as ''X. aff. couchianus'', was discovered in Apodaca, central Monterrey, in 1983. It has large black blotching, unlike the typical, unspotted form from the Huasteca Canyon. Whether the Apodaca form represents a separate species is presently unclear. Sexual dimorphism is moderate, the male Monterrey platyfish growing to a maximum overall length of and the female . Conservation IUCN lists the Monterrey platyfish as "e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Frédéric Girard
Charles Frédéric Girard (8 March 1822 – 29 January 1895) was a French biologist specializing in ichthyology and herpetology. Born in Mulhouse, France, he studied at the College of Neuchâtel, Switzerland, as a student of Louis Agassiz. In 1847, he accompanied Agassiz as his assistant to Harvard University. Three years later, Spencer Fullerton Baird called him to the Smithsonian Institution to work on its growing collection of North American reptiles, amphibians and fishes. He worked at the museum for the next ten years and published numerous papers, many in collaboration with Baird. In 1854, he was naturalized as a U.S. citizen. Besides his work at the Smithsonian, he managed to earn an M.D. from Georgetown University in Washington, D.C. in 1856. In 1859 he returned to France and was awarded the Cuvier Prize by the Institute of France for his work on the North American reptiles and fishes two years later. When the American Civil War broke out, he joined the Confederate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1859
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Most fis ... [...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] |
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] |
Marbled Swordtail
The marbled swordtail (''Xiphophorus meyeri'') is a species of freshwater fish in the family Poeciliidae. It was endemic to the Rio Salado system (itself a part of the Rio Grande basin) in Coahuila, northeastern Mexico. It was restricted to springs, connected creeks and pools in waters with a pH slightly above neutral and temperatures of , with captive studies indicating that the optimum temperature is around . The marbled swordtail is considered extinct in the wild by the IUCN with the last wild record in 1997, meaning that it survives only in captivity. Captive populations are maintained at the ''Xiphophorus'' Genetic Stock Center, Texas State University, United States, and by XNP conservation project members, which include public aquariums, universities and private aquarists in several European countries and the United States. The marbled swordtail shares the title as northernmost naturally distributed ''Xiphophorus'' with the closely related Monterrey platyfish (''X. couc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Platyfish
The northern platyfish (''Xiphophorus gordoni'') is a small, endangered species of fish in the family Poeciliidae. It is endemic to the vicinity of Cuatro Ciénegas in the Mexican state of Coahuila. It is restricted to hot-spring heated ditches and marshes of the Laguna Santa Tecla. Its native water is shallow and vegetation-choked, with very stable temperatures that generally are around , although captive studies show the species also can live in slightly colder water. The species is primarily threatened by habitat loss due to construction of irrigation channels. Captive "safety" populations are kept at the ''Xiphophorus'' Genetic Stock Center, Texas State University, United States, and by XNP conservation project members, which include public aquariums, universities and private aquarists in several European countries and the United States. It was named in honor of Myron Gordon by Robert Rush Miller and W. L. Minckley who discovered it with Carl Hubbs on a 1961 expedition. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas State University
Texas State University is a public research university in San Marcos, Texas. Since its establishment in 1899, the university has grown to the second largest university in the Greater Austin metropolitan area and the fifth largest university in the state of Texas. Texas State University reached a record enrollment of 38,808 students in the 2016 fall semester, continuing a trend of enrollment growth over several years. The university offers more than 200 degree options from its ten colleges. Texas State is classified among "R2: Doctoral Universities – High research activity" and an emerging research university by the State of Texas. The university is accredited by the Southern Association of Colleges and Schools (SACS). Faculty from the various colleges have consistently been granted Fulbright Scholarships resulting in Texas State's being recognized as one of the top producing universities of Fulbright Scholars. The 36th president of the United States, Lyndon B. Johnson, gra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Stock Center
Genetic stock centers are collections of pure genetic stock available for use in research. They are often housed at research universities, and include everything from single cell life to plants, fish, and small mammals such as mice and rats. Genetic Stock Centers often charge for research stock on a two tier scale, with non profit researchers getting stock at a lower cost than commercial researchers. Dr Myron Gordon, for example, established the 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 s ... genetic stock center in 1939 to raise pure strains when he realized that certain Xiphophorus hybrids would be useful in cancer research. He understood that his research could not be duplicated by other scientists without pure genetic stock to use as a base. The strains that Dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universidad Autónoma De Nuevo León
Universidad (Spanish for "university") may refer to: Places * Universidad, San Juan, Puerto Rico * Universidad (Madrid) Football clubs * Universidad SC, a Guatemalan football club that represents the Universidad de San Carlos de Guatemala * Universidad Católica, Chilean football club * Universidad de Chile (football club), Chilean football club * Club Universidad Nacional or ''UNAM Pumas'', Mexican football club * Universidad de Los Andes FC, Venezuelan football club * Universidad San Carlos or ''USAC'', Guatemalan football club * Universidad de Santa Cruz Bolivian football Club currently playing Bolivian Football Regional Leagues * Universidad Independiente, a former club based in San Pedro Sula, Honduras, dissolved in 2010 See also * * Universidad station (other) Universidad station may refer to: * Universidad station (Medellín), Colombia *Universidad metro station (Mexico City), Mexico *Universidad station (Puerto Rico), in San Juan * Universidad metro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introduced Species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, directly or indirectly, and either deliberately or accidentally. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are considered naturalized. The process of human-caused introduction is distinguished from biological colonization, in which species spread to new areas through "natural" (non-human) means such as storms and rafting. The Latin expression neobiota captures the characteristic that these species are ''new'' biota to their environment in terms of established biological network (e.g. food web) relationships. Neobiota can further be divided into neozoa (also: neozoons, sing. neozoon, i.e. animals) and neophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urban Sprawl
Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city." Urban sprawl has been described as the unrestricted growth in many urban areas of housing, commercial development, and roads over large expanses of land, with little concern for urban planning. In addition to describing a special form of urbanization, the term also relates to the social and environmental consequences associated with this development. Medieval suburbs suffered from loss of protection of city walls, before the advent of industrial warfare. Modern disadvantages and costs include increased travel time, transport costs, pollution, and destruction of the countryside. The cost of building urban infrastructure for new developments is hardly ever recouped through property taxes, amounting to a subsidy for the developers and new residents at the expense of existing property taxpayers. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
