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Satan (fish)
The widemouth blindcat (''Satan eurystomus'') is a species of North American freshwater catfish endemic to Texas in the United States. It is the only species in the genus ''Satan''. Description It was first discovered inhabiting a well, and is adapted for a lightless underground environment. Like other cavefish, the widemouth blindcat lacks pigmentation and has no externally visible eyes. The eye remnants are extremely reduced in size with very little or no trace of a retina or lens; the optic tract is present, but always regresses before reaching the brain. The swim bladder in these fish is reduced, and the skull is mostly cartilaginous and not well-ossified, unlike the adults of most larger ictalurids. The lateral line is fragmentary and never reaches past the anterior part of the anal fin. This species also has a few paedomorphic traits (indicated by small size, kidney morphology, and weak ossification of the skeleton). This species grows to about TL. Taxonomy The widemouth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Leavitt Hubbs
Carl Leavitt Hubbs (October 19, 1894 – June 30, 1979) was an American ichthyologist. Biography Early life Carl Leavitt Hubbs was born in Williams, Arizona, to Charles Leavitt and Elizabeth () Hubbs. His father had a wide variety of jobs (farmer, iron mine owner, newspaper owner). The family moved several times before settling in San Diego where he got his first taste of natural history. After his parents divorced in 1907, he lived with his mother, who opened a private school in Redondo Beach, California. His maternal grandmother Jane Goble Goss, one of the first female doctors, showed Hubbs how to harvest shellfish and other sea creatures. One of his teachers, impressed by Hubbs's abilities in science, recommended that he study chemistry at the University of Berkeley. The family moved once more to Los Angeles. In Los Angeles, George Bliss Culver, one of the many volunteers of David Starr Jordan, encouraged Hubbs to abandon his study of birds and instead to study fish, part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paedomorphosis
Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the Physiology, physiological, or Somatic (biology), somatic, development of an organism, typically an animal. Neoteny in humans, Neoteny in modern humans is more significant than in other primates. In progenesis or paedogenesis, sexual development is accelerated. Both neoteny and progenesis result in paedomorphism (as having the form typical of children) or paedomorphosis (changing towards forms typical of children), a type of heterochrony. It is the retention in adults of traits previously seen only in the young. Such retention is important in evolutionary biology, domestication, and evolutionary developmental biology. Some authors define paedomorphism as the retention of larval traits, as seen in salamanders.Schell, S. C. ''Handbook of Trematodes of North America North of Mexico'', 1985, pg. 22 History and etymology Julius Kollmann created the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered Species Act Of 1973
The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting and conserving imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation", the ESA was signed into law by President Presidency of Richard Nixon#Environmental policy, Richard Nixon on December 28, 1973. The Supreme Court of the United States described it as "the most comprehensive legislation for the preservation of endangered species enacted by any nation"."Tennessee Valley Authority v. Hill" 437 U.S. 153 (1978) Retrieved 24 November 2015. The purposes of the ESA are two-fold: to prevent extinction and to recover species to the point wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Pollution
Groundwater pollution (also called groundwater contamination) occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution (or contamination) can also occur from naturally occurring contaminants, such as arsenic contamination of groundwater, arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease (Waterborne diseases, water-borne diseases). The pollutant often produces a contaminant Plume (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. In 2012 there were 5,196 animals and 6,789 plants classified as vulnerable, compared with 2,815 and 3,222, respectively, in 1998. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A taxon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Top Carnivore
An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic levels. Food chains are often far shorter on land, usually limited to being secondary consumers – for example, wolves prey mostly upon large herbivores (primary consumers), which eat plants (primary producers). The apex predator concept is applied in wildlife management, conservation, and ecotourism. Apex predators have a long evolutionary history, dating at least to the Cambrian period when animals such as ''Anomalocaris'' and ''Timorebestia'' dominated the seas. Humans have for many centuries interacted with other apex predators including the wolf, birds of prey, and cormorants to hunt game animals, birds, and fish respectively. More recently, humans have started interacting with apex predators in new ways. These include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exoskeleton
An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that of a human) which is enclosed underneath other soft tissues. Some large, hard and non-flexible protective exoskeletons are known as mollusc shell, shell or armour (anatomy), armour. Examples of exoskeletons in animals include the arthropod exoskeleton, cuticle skeletons shared by arthropods (insects, chelicerates, myriapods and crustaceans) and tardigrades, as well as the corallite, skeletal cups formed by hardened secretion of stony corals, the test (biology), test/tunic of sea squirts and sea urchins, and the prominent mollusc shell shared by snails, bivalvia, clams, tusk shells, chitons and nautilus. Some vertebrate animals, such as the turtle, have both an endoskeleton and a turtle shell, protective exoskeleton. Role Exoskeletons c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthropods including decapods (shrimps, prawns, crabs, lobsters and crayfish), seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, opossum shrimps, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods (insects and entognathans) emerged deep in the Crustacean group, with the completed pan-group referred to as Pancrustacea. The three classes Cephalocarida, Branchiopoda and Remipedia are more closely related to the hexapods than they are to any of the other crustaceans ( oligostracans and multicrustaceans). The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Antonio
San Antonio ( ; Spanish for " Saint Anthony") is a city in the U.S. state of Texas and the most populous city in Greater San Antonio. San Antonio is the third-largest metropolitan area in Texas and the 24th-largest metropolitan area in the United States at 2.6 million people in the 2020 United States census. It is the most populous city in and the county seat of Bexar County. San Antonio is the seventh-most populous city in the United States, and the second-most populous in the Southern United States and Texas, after Houston. Founded as a Spanish mission and colonial outpost in 1718, the city in 1731 became the first chartered civil settlement in what is now present-day Texas. The area was then part of the Spanish Empire. From 1821 to 1836, it was part of the Mexican Republic. It is the oldest municipality in Texas, having celebrated its 300th anniversary on May 1, 2018. Straddling the regional divide between South and Central Texas, San Antonio anchors the southwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edwards Aquifer
The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water supply for agriculture and industry in the aquifer's region. Additionally, the Edwards Aquifer feeds the Comal River, Comal and San Marcos Springs, provides springflow for recreational and downstream uses in the Nueces River, Nueces, San Antonio River, San Antonio, Guadalupe River (Texas), Guadalupe, and San Marcos River, San Marcos river basins, and is home to several unique and endangered species. Basin characteristics Geography Located in South Central Texas, the Edwards Aquifer encompasses an area of approximately that extends into parts of 11 counties. The aquifer's boundaries begin at the groundwater divide in Kinney County, East of Brackettville, and extend Eastward through the San Antonio area and then Northeast where the aquif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artesian Wells
An artesian well is a well that brings groundwater to the surface without pumping because it is under pressure within a body of rock or sediment known as an aquifer. When trapped water in an aquifer is surrounded by layers of impermeable rock or clay, which apply positive pressure to the water, it is known as an artesian aquifer. If a well were to be sunk into an artesian aquifer, water in the well-pipe would rise to a height corresponding to the point where hydrostatic equilibrium is reached. A well drilled into such an aquifer is called an ''artesian well''. If water reaches the ground surface under the natural pressure of the aquifer, the well is termed a ''flowing artesian well''. Fossil water aquifers can also be artesian if they are under sufficient pressure from the surrounding rocks, similar to how many newly tapped oil wells are pressurized. Not all aquifers are artesian (i.e., water table aquifers occur where the groundwater level at the top of the aquifer is at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toothless Blindcat
The toothless blindcat (''Trogloglanis pattersoni'') is a species of North American freshwater catfish endemic to Texas in the United States. Description The toothless blindcat has no pigmentation and no externally visible eyes. The eye remnants are extremely reduced in size, with very little or no trace of a retina or lens; the optic tract is present, but always regresses before reaching the brain. In juveniles, the eye is under the skin, but as the fish grows, the eyes are withdrawn even further. The head is as long as it is broad. The adipose fin is long and rounded at the end, and is connected to the caudal fin. The dorsal and pectoral fins have spines. The swim bladder in these fish is reduced. The stomach is reduced in size and surrounded by deposits of adipose tissue allowing for adequate energy to be stored. The skull is mostly cartilaginous and not well-ossified, unlike the adults of most larger ictalurids. The lateral line is fragmented and reaches to between the anterio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
