|
San Marcos Salamander
The San Marcos salamander (''Eurycea nana'') is a small species of aquatic, lungless salamander native to the United States, endemic to Spring Lake and a small region of the headwaters of the San Marcos River near Aquarena Springs, in Hays County, Texas. It is one to two inches long, with a slender body and external gills, and is a reddish-brown in color. Description ''E. nana'' is an aquatic salamander. It does not leave the water to change into a terrestrial form, but rather matures in the water. As a neotenic form, ''E. nana'' retains its gills for its lifetime. The San Marcos salamander has a narrow head with a round snout, large eyes, and a dark iris. External gills are developed and pigmented. 2-6 palatopterygoid and 7-13 premaxillary teeth are present. The species is uniformly light brown in color, with a series of seven to nine irregular light spots present along its midline. The trunk is flattened above with a dorsal furrow that extends from head to tail. The venter, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Largemouth Bass
The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but widely introduced elsewhere. It is known by a variety of regional names, such as the widemouth bass, bigmouth bass, black bass, bucketmouth, largies, Potter's fish, Florida bass, Florida largemouth, green bass, bucketmouth bass, Green trout, gilsdorf bass, Oswego bass, LMB, and southern largemouth and northern largemouth. The largemouth bass is the state fish of Georgia and Mississippi, and the state freshwater fish of Florida and Alabama. Taxonomy The largemouth bass was first formally described as ''Labrus salmoides'' in 1802 by the French naturalist Bernard Germain de Lacépède with the type locality given as the Carolinas. Lacépède based his description on an illustration of a specimen collected by Louis Bosc near Charleston, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Fauna Of Texas
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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Marcos, Texas
San Marcos ( ) is a city and the county seat of Hays County, Texas, United States. The city's limits extend into Caldwell and Guadalupe Counties, as well. San Marcos is within the Austin–Round Rock metropolitan area and on the Interstate 35 corridor between Austin and San Antonio. Its population was 44,894 at the 2010 census and 67,553 at the 2020 census. Founded on the banks of the San Marcos River, the area is thought to be among the oldest continuously inhabited sites in the Americas. San Marcos is home to Texas State University and the Meadows Center for Water and the Environment."Meadows Center for Water and the Environment : Texas State University" In 2010, San Marcos was listed in '' |
Batrachochytrium Dendrobatidis
''Batrachochytrium dendrobatidis'' ( ), also known as ''Bd'' or the amphibian chytrid fungus, is a fungus that causes the disease chytridiomycosis in amphibians. Since its discovery in 1998 by Lee Berger, the disease devastated amphibian populations around the world, in a global decline towards multiple extinctions, part of the Holocene extinction. A recently described second species, '' B. salamandrivorans'', also cause chytridiomycosis and death in salamanders. The fungal pathogens that cause the disease chytridiomycosis ravage the skin of frogs, toads, and other amphibians, throwing off their balance of water and salt and eventually causing heart failure, Nature reports. Some amphibian species appear to have an innate capacity to withstand chytridiomycosis infection due to symbiosis with ''Janthinobacterium lividum''. Even within species that generally succumb, some populations survive, possibly demonstrating that these traits or alleles of species are being subjected to evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsporidia
Microsporidia are a group of spore-forming unicellular parasites. These spores contain an extrusion apparatus that has a coiled polar tube ending in an anchoring disc at the apical part of the spore. They were once considered protozoans or protists, but are now known to be fungi, or a sister group to fungi. These fungal microbes are obligate eukaryotic parasites that use a unique mechanism to infect host cells. They have recently been discovered in a 2017 Cornell study to infect Coleoptera on a large scale. So far, about 1500 of the probably more than one million species are named. Microsporidia are restricted to animal hosts, and all major groups of animals host microsporidia. Most infect insects, but they are also responsible for common diseases of crustaceans and fish. The named species of microsporidia usually infect one host species or a group of closely related taxa. Approximately 10 percent of the species are parasites of vertebrates —several species, most of which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kyphosis
Kyphosis is an abnormally excessive convex curvature of the spine as it occurs in the thoracic and sacral regions. Abnormal inward concave ''lordotic'' curving of the cervical and lumbar regions of the spine is called lordosis. It can result from degenerative disc disease; developmental abnormalities, most commonly Scheuermann's disease; Copenhagen disease, osteoporosis with compression fractures of the vertebra; multiple myeloma; or trauma. A normal thoracic spine extends from the 1st thoracic to the 12th thoracic vertebra and should have a slight kyphotic angle, ranging from 20° to 45°. When the "roundness" of the upper spine increases past 45° it is called kyphosis or "hyperkyphosis". Scheuermann's kyphosis is the most classic form of hyperkyphosis and is the result of wedged vertebrae that develop during adolescence. The cause is not currently known and the condition appears to be multifactorial and is seen more frequently in males than females. In the sense of a deformit ... [...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 and San Marcos springs, provides springflow for recreational and downstream uses in the Nueces, San Antonio, Guadalupe, and 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 aquifer boundary ends at the Leon River in Bell County.Tremallo, Robin; Hamiton, Mark; Johns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Threatened Species
Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensation'', a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment. IUCN definition The International Union for Conservation of Nature (IUCN) is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened: *Vulnerable species *Endangered species * Critically endangered species Less-than-threatened categories are near threatened, least concern, and the no longer assigned category of conservation dependent. Species which have not been evaluated (NE), or do not have sufficient data ( data deficient) also are not considered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanophores
Chromatophores are cells that produce color, of which many types are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. Mammals and birds, in contrast, have a class of cells called melanocytes for coloration. Chromatophores are largely responsible for generating skin and eye colour in ectothermic animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour (more properly "hue") under white light: xanthophores (yellow), erythrophores (red), iridophores (reflective / iridescent), leucophores (white), melanophores (black/brown), and cyanophores (blue). While most chromatophores contain pigments that absorb specific wavelengths of light, the color of leucophores and iridophores is produced by their respective scattering and optical interference properties. Some species can rapidly change colour through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg Cell
The egg cell, or ovum (plural ova), is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capable of movement (non-motile). If the male gamete (sperm) is capable of movement, the type of sexual reproduction is also classified as oogamous. A nonmotile female gamete formed in the oogonium of some algae, fungi, oomycetes, or bryophytes is an oosphere. When fertilized the oosphere becomes the oospore. When egg and sperm fuse during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism. History While the non-mammalian animal egg was obvious, the doctrine ''ex ovo omne vivum'' ("every living nimal comes froman egg"), associated with William Harvey (1578–1657), was a rejection of spontaneous generation and preformationism as well as a bold assumption that mammals also reproduced via ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Endemic Fauna Of Texas")
