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Megupsilon
The Catarina pupfish (''Megupsilon aporus'') was a diminutive species of fish in the family Cyprinodontidae, first described in 1972. It was Endemism, endemic to a spring in Nuevo León, Mexico. In an attempt of saving the rapidly declining species, some were brought into captivity in the late 1980s and early 1990s, but it proved very difficult to maintain. In 1994 it became extinct in the wild. Gradually the captive populations also perished. The last male died in 2014 (pictured in inset) and the species became extinct. In addition to its small size, it was characterized by absence of List of ichthyology terms, pelvic girdle and Fish fin#AnchVentral, pelvic fins, novel male reproductive behavior of jaw-nudging, a darkened dorsal patch, and by having different numbers of chromosomes in male and female fish due to a recent chromosomal fusion event. In 2013, its behavior was described based on very limited field observations of the previous wild population and more detailed observat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megupsilon
The Catarina pupfish (''Megupsilon aporus'') was a diminutive species of fish in the family Cyprinodontidae, first described in 1972. It was Endemism, endemic to a spring in Nuevo León, Mexico. In an attempt of saving the rapidly declining species, some were brought into captivity in the late 1980s and early 1990s, but it proved very difficult to maintain. In 1994 it became extinct in the wild. Gradually the captive populations also perished. The last male died in 2014 (pictured in inset) and the species became extinct. In addition to its small size, it was characterized by absence of List of ichthyology terms, pelvic girdle and Fish fin#AnchVentral, pelvic fins, novel male reproductive behavior of jaw-nudging, a darkened dorsal patch, and by having different numbers of chromosomes in male and female fish due to a recent chromosomal fusion event. In 2013, its behavior was described based on very limited field observations of the previous wild population and more detailed observat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potosi Pupfish
Potosi pupfish (''Cyprinodon alvarezi'') is a species of fish in the family Cyprinodontidae. It is endemic to Mexico, but is now extinct in the wild, only surviving in captivity. Distribution The Potosi pupfish is endemic to an isolated spring known as Ojo de Potosi near El Potosi, a settlement in southwestern Nuevo Leon state in Mexico. However, the species is now regarded as being extinct in the wild, and is represented only by captive populations. Habitat and extinction in the wild The Potosi pupfish is endemic to a clear spring-fed pool in an endorheic basin known as 'La Hediondilla' near the foot of Cerro Potosi. The pool had a maximum depth of 2.5 meters, and surface area of 10,000 m2, covered by abundant vegetation including ''Ceratophyllum, Najas, Nasturtium,'' and ''Utricularia.'' Sparse clumps of '' Typha'' and ''Scirpus'' were also present in the spring. A large earthen and rock dam enlarged the original pool, and a series of seeps and secondary outflows creat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Rush Miller
Robert Rush Miller (April 23, 1916 – February 10, 2003) "was an important figure in American ichthyology and conservation from 1940 to the 1990s." He was born in Colorado Springs, earned his bachelor's degree at University of California, Berkeley in 1938, a master's degree at the University of Michigan in 1943, and a Ph.D. at the University of Michigan in 1944. He received tenure at the University of Michigan in 1954. Together with W. L. Minckley, he discovered a new species of platyfish, '' Xiphophorus gordoni'', that they named in honor of Dr Myron Gordon. He served as the ichthyological editor of ''Copeia'' from 1950 to 1955. Fish described * '' Chortiheros wesseli'' R. R. Miller 1996 - Cichlid * ''Cualac tessellatus'' R. R. Miller 1956 - (Checkered Pupfish) * '' Cyprinodon albivelis'' W. L. Minckley & R. R. Miller, 2002 (Whitefin pupfish) * '' Cyprinodon alvarezi'' R. R. Miller, 1976 (Potosi pupfish) * '' †Cyprinodon arcuatus'' W. L. Minckley & R. R. Miller, 2002 (Santa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Clock
The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins. The benchmarks for determining the mutation rate are often fossil or archaeological dates. The molecular clock was first tested in 1962 on the hemoglobin protein variants of various animals, and is commonly used in molecular evolution to estimate times of speciation or radiation. It is sometimes called a gene clock or an evolutionary clock. Early discovery and genetic equidistance The notion of the existence of a so-called "molecular clock" was first attributed to Émile Zuckerkandl and Linus Pauling who, in 1962, noticed that the number of amino acid differences in hemoglobin between different lineages changes roughly linearly with time, as estimated from fossil evidence. ... [...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] |
Phenotypic Plasticity
Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes (e.g. morphological, physiological, behavioural, phenological) that may or may not be permanent throughout an individual's lifespan. The term was originally used to describe developmental effects on morphological characters, but is now more broadly used to describe all phenotypic responses to environmental change, such as acclimation (acclimatization), as well as learning. The special case when differences in environment induce discrete phenotypes is termed polyphenism. Generally, phenotypic plasticity is more important for immobile organisms (e.g. plants) than mobile organisms (e.g. most animals), as mobile organisms can often move away from unfavourable environments. Nevertheless, mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrine System
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland and the adrenal glands. The study of the endocrine system and its disorders is known as endocrinology. Glands that signal each other in sequence are often referred to as an axis, such as the hypothalamic-pituitary-adrenal axis. In addition to the specialized endocrine organs mentioned above, many other organs that are part of other body systems have secondary endocrine functions, including bone, kidneys, liver, heart and gonads. For example, the kidney secretes the endocrine hormone erythropoietin. Hormones can be amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins. The endocrine system can be contrasted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossification
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue ( mesenchyme), while endochondral ossification involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floridichthys
''Floridichthys'' is a genus of pupfishes native to the southeastern United States, Mexico and northern Central America. The name of this genus is a compound of Florida and the Greek for "fish", ''ichthys''. The ichthyologist Carl Leavitt Hubbs Carl Leavitt Hubbs (October 19, 1894 – June 30, 1979) was an American ichthyologist. Biography Youth He was born in Williams, Arizona. He was the son of Charles Leavitt and Elizabeth (née Goss) Hubbs. His father had a wide variety of jobs (f ... thought that the genus was confined to Florida at the time he coined the name. Species There are currently two recognized species in this genus: * '' Floridichthys carpio'' ( Günther, 1866) (Goldspotted killifish) * '' Floridichthys polyommus'' C. L. Hubbs, 1936 (Ocellated killifish) References Cyprinodontidae Freshwater fish genera Taxa named by Carl Leavitt Hubbs {{Cyprinodontiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garmanella Pulchra
The Yucatan flagfish (''Garmanella pulchra''), also known as the snakeskin killifish, is a species of pupfish from the family Cyprinodontidae. It is found in the coastal waters (both fresh and brackish) of the Yucatan Peninsula, in Mexico and Belize. This species grows to a length of TL and is found in the aquarium trade. This species was described by Carl Leavitt Hubbs in 1936 with the type locality given as east of Progreso, Yucatán, Mexico. It is the only known member of its genus. The name of the genus commemorates the American ichthyologist Samuel Garman (1843-1927) who was working on a revision of his 1895 monograph on the Cyprinodontidae at the time of his death. It is sometimes treated as a junior synonym of ''Jordanella''. The Yucatan flagfish is found in coastal brackish water systems and inland freshwaters with hard water over substrates of marl, sand, decomposing vegetation, rocks and mud. It is mainly herbivorous, its diet largely being made up of microalgae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosome
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes is collectively known as atDNA or auDNA. For example, humans have a diploid human genome, genome that usually contains 22 pairs of autosomes and one allosome pair (46 chromosomes total). The autosome pairs are labeled with numbers (1–22 in humans) roughly in order of their sizes in base pairs, while allosomes are labelled with their letters. By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations of XYY syndrome, XYY, Klinefelter syndrome, XXY, Triple X syndrome, XXX, XXXX syndrome, XXXX, XXXXX syndrome, XXXXX or XXYY syndrome, XXYY, among Aneuploidy, other Salome combinations, are known to occur and usually cause developmental abnormalities. Autosomes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y Chromosome
The Y chromosome is one of two sex chromosomes (allosomes) in therian mammals, including humans, and many other animals. The other is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 59 million base pairs, making it similar in size to chromosome 19. The Y chromosome is passed only from father to son. With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome. The human Y chromosome carries an estimated 100–200 genes, with between 45 and 73 of these being protein-coding. All single-copy Y-linked genes are hemizygous (present on only one chromosome) except in cases of aneuploidy such as XYY syndrome or XXYY syndrome. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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