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Xiphophorus Milleri
''Xiphophorus milleri'', the Catemaco platyfish, is a poeciliid fish endemic to Mexico's Lake Catemaco and its tributaries. As it has traits of both swordtails and platies, its discovery confirmed that these two groups should be consolidated into a single genus, ''Xiphophorus''. Taxonomy The species was named after American ichthyologist Robert Rush Miller, who collected it along with other ''Xiphophorus'' species. Its discovery enabled scientists to definitely conclude that platies and swordtails should be classified in the same genus, for it combines traits that were thought to separate platies from swordtails into different genera. Namely, ''X. milleri'' resembles the swordtails in body shape, pigmentation, and ecology, but shares the platies' secondary sexual characteristics, pigmentary polymorphism, and the absence of a sword. Description ''Xiphophorus milleri'' is a small to medium ''Xiphophorus'' species. Its body is slender. Nearly a half of specimens have melanophore ... [...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. Donn E. Rosen married Carmela Berritto, and they had three sons, one of whom, Philip Clark Rosen (1955-2020) was a herpetologist and ecologist, who spent many years studying the Sonoran Desert. Works Rosen earned his degree in 1955, his master's in 1957, and his doctorate in 1959, all from New York University. In 1961 he joined the staff of the American Museum of Natural History, and was chairman of the department of ichthyology from 1965 to 1975, presiding over a collection that grew from 500,000 to 1.5 mill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus Montezumae
''Xiphophorus montezumae'', the Montezuma swordtail, is a livebearing freshwater fish of the order Cyprinodontiformes, family Poeciliidae, and genus ''Xiphophorus''. It is in the same genus as the common platy and the swordtail. ''Xiphophorus'' means 'sword-bearer' in Greek. Description Growing to a maximum length of around , the females are larger in size than the males. The genus ''Xiphophorus'' is common in freshwater aquariums An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati .... The males of this particular species are known for their metallic green scales and the fact that their "sword" stays horizontal unlike most species where it is angled downward. References General references Live-bearing fish Ovoviviparous fish montezumae Freshwater fish of Mexico Fish descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Fish Of Mexico
Endemism is the state of a species being found only 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 also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or becomi ... [...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. The term excludes seawater and brackish water, but 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. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of vascular plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh water is the water resource that is of the most and immediate use to humans. Fresh water is not alway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filial Cannibalism
Filial cannibalism occurs when an adult individual of a species consumes all or part of the young of its own species or immediate offspring. Filial cannibalism occurs in many species ranging from mammals to insects, and is especially prevalent in various types of fish species with males that engage in egg guardianship. The exact purpose of the practice in those species is uncertain, but zoologists have proposed several explanations based on evolutionary and ecological principles. Types Total Total or whole clutch cannibalism occurs when a parent consumes its entire brood. This usually occurs when a brood is small or of lower quality. The most obvious purpose of total or whole clutch cannibalism is the termination of care for the parents. The main benefit of this action can only be an investment in the future reproduction of potentially larger or healthier broods. Partial Partial clutch cannibalism occurs when a parent consumes a part of its offspring. "Parental manipulation of br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ovoviviparity
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous amphibians, such as '' Limnonectes larvaepartus'', are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera '' Nectophrynoides'' and '' Eleutherodactylus'' bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth. Among insects that depend on opportunistic exploitation of transient food sources, such as many Sarcophagidae and other carrion flies, and species such as many Calliphoridae, that rely on fresh dung, and parasitoids such as tachinid flies that depend on entering the host as soon as possible, the embryos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livebearer
Livebearers are fish that retain their eggs inside the body and give birth to live, free-swimming young. They are especially prized by aquarium owners. Among aquarium fish, livebearers are nearly all members of the family Poeciliidae and include: guppy, molly, platy, endler’s and swordtails. The advantages of livebearing to the aquarist are that the newborn juvenile fish are larger than newly-hatched fry, have a lower chance of mortality and are easier to care for. Unusual livebearers include seahorses and pipefish, where the males care for the young, and certain cichlids that are mouthbrooders, with the parent incubating the eggs in the buccal cavity. Common aquarium livebearers Species of interest to aquarists are almost always members of the family Poeciliidae, most commonly guppies, mollies, platies, swordtails, Endler's livebearer, and mosquitofish. Most of these are ovoviviparous, with the developing embryos receiving no nourishment from the parent fish, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus Helleri
The green swordtail (''Xiphophorus hellerii'') is a species of freshwater/brackish fish in family Poeciliidae of order Cyprinodontiformes. A live-bearer, it is closely related to the southern platyfish or 'platy' (''X. maculatus'') and can crossbreed with it. It is native to an area of North and Central America stretching from Veracruz, Mexico, to northwestern Honduras. Description The male green swordtail grows to a maximum overall length of and the female to . The name 'swordtail' is derived from the elongated lower lobe of the male's caudal fin (tailfin). Sexual dimorphism is moderate, with the female being larger than the male, but lacking the 'sword'. The wild form is olive green in color, with a red or brown lateral stripe and speckles on the dorsal and, sometimes, caudal fins. The male's 'sword' is yellow, edged in black below. Captive breeding has produced many color varieties, including black, red, and many patterns thereof, for the aquarium hobby. All varieties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Water
Whitewater forms in the context of rapids, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white. The term "whitewater" also has a broader meaning, applying to any river or creek that has a significant number of rapids. The term is also used as an adjective describing boating on such rivers, such as whitewater canoeing or whitewater kayaking. Fast rivers Four factors, separately or in combination, can create rapids: gradient, constriction, obstruction, and flow rate. Gradient, constriction, and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams. Streambed topography Streambed topography is the primary factor in creating rapids, and is generally consistent over time. Increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Length
Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured from the tip of the snout to the posterior end of the last vertebra or to the posterior end of the midlateral portion of the hypural plate. This measurement excludes the length of the caudal (tail) fin. Total length (TL) is the length of a fish measured from the tip of the snout to the tip of the longer lobe of the caudal fin, usually measured with the lobes compressed along the midline. It is a straight-line measure, not measured over the curve of the body. Standard length measurements are used with Teleostei (most bony fish), while total length measurements are used with Myxini (hagfish), Petromyzontiformes ( lampreys) and usually Elasmobranchii (shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ... [...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 tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xiphophorus Maculatus
''Xiphophorus'' is a genus of euryhaline and freshwater fishes in the family Poeciliidae of order Cyprinodontiformes, native to Mexico and northern Central America. ''Xiphophorus'' species can be divided into three groups based on their evolutionary relationships: platyfish (or platies), northern swordtails, and southern swordtails. Platyfish formerly were classified in another genus, ''Platypoecilus'', 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 ''Xi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
