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Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broad sense, it is paraphyletic group encompassing all tetrapods excluding the amniotes. All extant (living) amphibians belong to the monophyletic subclass Lissamphibia, with three living orders: Anura (frogs), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater, wetland or terrestrial ecosystems. Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, but some species have developed behavioural adaptations to bypass this.
Neoteny, also called juvenilization, is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compared to other primates. In progenesis or paedogenesis, sexual development is accelerated.
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 from the group Caudata. 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.
The axolotl is a paedomorphic salamander closely related to the tiger salamander. It is unusual among amphibians in that it reaches adulthood without undergoing metamorphosis. Instead of taking to the land, adults remain aquatic and gilled. The species was originally found in several lakes underlying what is now Mexico City, such as Lake Xochimilco and Lake Chalco. These lakes were drained by Spanish settlers after the conquest of the Aztec Empire, leading to the destruction of much of the axolotl's natural habitat.
The tiger salamander is a species of mole salamander and one of the largest terrestrial salamanders in North America.
Agamidae is a family of over 550 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards.
The spotted salamander or yellow-spotted salamander is a mole salamander common in eastern United States and Canada. It is the state amphibian of Ohio and South Carolina. The species ranges from Nova Scotia, to Lake Superior, to southern Georgia and Texas. Its embryos have been found to have symbiotic algae living in and around them, the only known example of vertebrate cells hosting an endosymbiont microbe.
The cerebellar vermis is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways.
The ringed salamander is a species of mole salamander native to hardwood and mixed hardwood-pine forested areas in and around the Ozark Plateau and Ouachita Mountains of Arkansas, Oklahoma, and Missouri. This species of salamander has slander body, small head, and long tail. They are usually found to have various dorsal color from dark gray to dark brown. Various close relatives are found such as marbled salamander and spotted salamander. This species of salamander has cannibal behavior especially those in large body size.
The long-toed salamander is a mole salamander in the family Ambystomatidae. This species, typically 4.1–8.9 cm (1.6–3.5 in) long when mature, is characterized by its mottled black, brown, and yellow pigmentation, and its long outer fourth toe on the hind limbs. Analysis of fossil records, genetics, and biogeography suggest A. macrodactylum and A. laterale are descended from a common ancestor that gained access to the western Cordillera with the loss of the mid-continental seaway toward the Paleocene.
The Lake Patzcuaro salamander, locally known as achoque, is a paedomorphic species of salamander found exclusively in Lake Pátzcuaro, a high-altitude lake in the Mexican state of Michoacán. First described in 1870 by Alfredo Dugès, the species is named in honor of the French herpetologist Auguste Duméril. However, the salamander has been used as a food source and an ingredient in traditional medicines by the Purépecha people since the Pre-Columbian era. Ambystoma dumerilii are neotenic, meaning they retain their larval characteristics throughout their entire life. This results in adults that have long, heavily filamented external gills, gill slits lined with tooth-like gill rakers, and caudal fins. When stressed, Ambystoma dumerilii can undergo an incomplete metamorphosis, though this is process significantly decreases their lifespan and is often fatal.
The granular salamander or ajolote is a species of mole salamander in the family Ambystomatidae. It is found only in Mexico. Its natural habitats are subtropical or tropical high-altitude grassland, freshwater marshes, intermittent freshwater marshes, and ponds. It is threatened by habitat loss and overcropping along with the scaling of their skins.
Nesting behavior refers to an instinct in animals during reproduction to prepare a place with optimal conditions for offspring. The nesting place provides protection against predators and competitors that mean to exploit or kill offspring. It also provides protection against the physical environment.
Enamel hypoplasia is a defect of the teeth in which the enamel is deficient in quantity, caused by defective enamel matrix formation during enamel development, as a result of inherited and acquired systemic condition(s). It can be identified as missing tooth structure and may manifest as pits or grooves in the crown of the affected teeth, and in extreme cases, some portions of the crown of the tooth may have no enamel, exposing the dentin. It may be generalized across the dentition or localized to a few teeth. Defects are categorized by shape or location. Common categories are pit-form, plane-form, linear-form, and localised enamel hypoplasia. Hypoplastic lesions are found in areas of the teeth where the enamel was being actively formed during a systemic or local disturbance. Since the formation of enamel extends over a long period of time, defects may be confined to one well-defined area of the affected teeth. Knowledge of chronological development of deciduous and permanent teeth makes it possible to determine the approximate time at which the developmental disturbance occurred. Enamel hypoplasia varies substantially among populations and can be used to infer health and behavioural impacts from the past. Defects have also been found in a variety of non-human animals.
In biology, a klepton and synklepton is a species that requires input from another biological taxon to complete its reproductive cycle. Specific types of kleptons are zygokleptons, which reproduce by zygogenesis; gynokleptons which reproduce by gynogenesis, and tychokleptons, which reproduce by a combination of both systems.
Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts. Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations, with variations in depth of calls the speed of calls and other complex behaviours to attract mates. The fittest males will have the deepest croaks and the best territories, with females making their mate choices at least partly based on the males depth of croaking. This has led to sexual dimorphism, with females being larger than males in 90% of species, males in 10% and males fighting for groups of females.
Parthenogenesis is a form of reproduction where eggs develop without fertilization, resulting in unisexual species. This phenomenon is closely related with reproductive modes such as hybridogenesis, where fertilization occurs, but the paternal DNA is not passed on. Among amphibians, it is seen in numerous frog and salamander species, but has not been recorded in caecilians.
Linear enamel hypoplasia (LEH) is a failure of the tooth enamel to develop correctly during growth, leaving bands of reduced enamel on a tooth surface. It is the most common type of enamel hypoplasia reported in clinical and archaeological samples, with other types including plane-form enamel hypoplasia and pitting enamel hypoplasia.
Elizabeth Adkins-Regan is an American comparative behavioral neuroendocrinologist best known for her research on the hormonal and neural mechanisms of reproductive behavior and sexual differentiation in birds. She is currently a professor emeritus in the Department of Psychology and the Department of Neurobiology and Behavior at Cornell University.
H. Jane Brockmann is an emeritus professor at the University of Florida known for her research on animal behavior, especially in the mating and nesting behavior of horseshoe crabs. In 2008, she was elected a fellow of the American Association for the Advancement of Science.
References
- ↑ "Jacqueline Jakway Obituary (2008) - Joplin, MO - The Joplin Globe". www.legacy.com.
- ↑ "Remembering the life of Jacqueline Sinks Jakway 2008". obituaries.joplinglobe.com.
- ↑ "Deaths JAKWAY, JACQUELINE SINKS". query.nytimes.com.
- ↑ Jakway, Jacqueline S.; Young, William C. (November 1958). "An Inherited Spermatogenic Hypoplasia in the Guinea Pig". Fertility and Sterility. 9 (6): 533–544. doi: 10.1016/s0015-0282(16)33244-7 . PMID 13619829.
- ↑ Goy, Robert W.; Jakway, Jacqueline S. (July 1959). "The inheritance of patterns of sexual behaviour in female guinea pigs". Animal Behaviour. 7 (3–4): 142–149. doi:10.1016/0003-3472(59)90003-x.
- ↑ Jakway, Jacqueline S. (July 1959). "Inheritance of patterns of mating behaviour in the male guinea pig". Animal Behaviour. 7 (3–4): 150–162. doi:10.1016/0003-3472(59)90004-1.
- ↑ Riss, W.; Jakway, Jacqueline S. (1970). "A Perspective on the Fundamental Retinal Projections of Vertebrates". Brain, Behavior and Evolution. 3 (1–4): 30–35. doi:10.1159/000125461. PMID 5522351.
- ↑ Jakway, Jacqueline S.; Riss, W. (1972). "Retinal Projections in the Tiger Salamander, Ambystoma tigrinum; pp. 425–442". Brain, Behavior and Evolution. 5 (6): 425–442. doi:10.1159/000123760.
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