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Eurycea Troglodytes
The Valdina Farms salamander (''Eurycea troglodytes'') is a species of aquatic salamander described from Valdina Farms Sinkhole in Medina County, Texas, United States. It is sometimes referred to as the Valdina blind salamander or sinkhole salamander. As some other species of '' Eurycea'' found in Texas, it was once classified as a subspecies of the Texas salamander, ''Eurycea neotenes'', and believed to possibly be the result of hybridization Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ... with another species of subterranean salamander, but was granted full species status in 2000. Research is ongoing, and some sources suggest the current species may actually be multiple distinct species. Description The Valdina Farms salamander grows from in length, with short legs, redu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), 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 reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), 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 binomial nomenclature, 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 specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela. Salamander diversity is highest in eastern North America, especially in the Appalachian Mountains; most species are found in the Holarctic realm, with some species present in the Neotropical realm. Salamanders rarely have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to the water intermittently, and others are entirely terrestrial as adults. This group of amphibians is capable of regenerating lost l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medina County, Texas
Medina County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 50,748. Its county seat is Hondo. The county is named for the Medina River. The extreme northern part of the county lies within the Edwards Plateau, which elevates into the Texas Hill Country. The Medina Dam, the fourth largest in the nation when completed in 1913, is listed on the National Register of Historic Places. The irrigation project, creating Medina Lake, was built by 1500 skilled workers who worked in shifts operating 24 hours a day to complete the dam in two years. Medina County is part of the San Antonio, TX Metropolitan Statistical Area. History The county is named after the Medina River, which was named in 1689 after the Spanish cartographer Pedro de Medina by the Spanish explorer Alonso de Leon, the first European to encounter the river. Because Pedro de Medina derived his surname from the Andalusian city of Medina-Sidonia, the name Medina comes from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are"). In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks. A taxonomist decides w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurycea Neotenes
''Eurycea neotenes'', also known as the Texas salamander, Bexar County salamander, Edwards Plateau salamander, or Texas neotenic salamander, is a species of entirely aquatic, lungless salamander native to the United States. It is endemic to central Texas, near Helotes, in Bexar County. Description The Texas salamander grows from in length. It is brown in color, often with yellow or brown mottling, with light-yellow spotting down its back. It is neotenic, with a slender body, short limbs, and bright-red external gills. The Texas salamander lives in caves, which resulted in reduced vision in its eyes, due to the long period of time in darkness. It is akin to the Texas blind salamander '' Eurycea rathbuni''. References * (2000): Phylogenetic relationships of central Texas hemidactyliine plethodontid salamanders, genus ''Eurycea'', and a taxonomic revision of the group. ''Herpetological Monographs'' 14: 1-80. * (2001): A new species of subterranean blind salamander ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in floweri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (pl. branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamellae (folds) contain blood or coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks, crustaceans, insects, fish, and amphibians. Semiterrestrial marine animals such as crabs and mudskippers have gill ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for lime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cave Salamanders
A cave salamander is a type of salamander that primarily or exclusively inhabits caves, a group that includes several species. Some of these animals have developed special, even extreme, adaptations to their subterranean environments. Some species have only rudimentary (or even absent) eyes (''blind salamanders''). Others lack pigmentation, rendering them a pale yellowish or pinkish color (e.g., '' Eurycea rathbuni''). With the notable exception of '' Proteus anguinus'', all "cave salamanders" are members of the family Plethodontidae ("lungless salamanders"). History The first dedicated scientific study of a cave animal was focused upon a cave salamander, '' Proteus anguinus''. It was originally identified as a "dragon's larva" by Johann Weikhard von Valvasor in 1689. Later, the Austrian naturalist Joseph Nicolaus Lorenz described it scientifically in 1768. Another early scientific description of a cave salamander was undertaken by Constantine Samuel Rafinesque in 1822 while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
