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.
Plethodontidae, or lungless salamanders, are a family of salamanders. Most species are native to the Western Hemisphere, from British Columbia to Brazil, although a few species are found in Sardinia, Europe south of the Alps, and South Korea. In terms of number of species, they are by far the largest group of salamanders.
In animal anatomy, a cloaca, plural cloacae, is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts of many vertebrate animals. All amphibians, reptiles and birds, and a few mammals, have this orifice, from which they excrete both urine and feces; this is in contrast to most placental mammals, which have two or three separate orifices for evacuation. Excretory openings with analogous purpose in some invertebrates are also sometimes referred to as cloacae. Mating through the cloaca is known as cloacal copulation, commonly referred to as cloacal kiss.
Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For internal fertilization to happen there needs to be a method for the male to introduce the sperm into the female's reproductive tract.
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism. External fertilization typically occurs in water or a moist area to facilitate the movement of sperm to the egg. The release of eggs and sperm into the water is known as spawning. In motile species, spawning females often travel to a suitable location to release their eggs.
Autotomy or self-amputation, is the behaviour whereby an animal sheds or discards one or more of its own appendages, usually as a self-defense mechanism to elude a predator's grasp or to distract the predator and thereby allow escape. Some animals have the ability to regenerate the lost body part later. Autotomy has multiple evolutionary origins and is thought to have evolved at least nine times independently in animals. The term was coined in 1883 by Leon Fredericq.
The spermatheca, also called receptaculum seminis, is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates. Its purpose is to receive and store sperm from the male or, in the case of hermaphrodites, the male component of the body. Spermathecae can sometimes be the site of fertilization when the oocytes are sufficiently developed.
Reptiliomorpha is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was defined by Michel Laurin (2001) and Vallin and Laurin (2004) as the largest clade that includes Homo sapiens, but not Ascaphus truei. Laurin and Reisz (2020) defined Pan-Amniota as the largest total clade containing Homo sapiens, but not Pipa pipa, Caecilia tentaculata, and Siren lacertina.
The Texas blind salamander is a rare cave-dwelling troglobite amphibian native to San Marcos, Hays County, Texas, specifically the San Marcos Pool of the Edwards Aquifer.
The Salamandroidea are a suborder of salamanders, referred to as advanced salamanders. The members of the suborder are found worldwide except for Antarctica, sub-Saharan Africa, and Oceania. They differ from suborder Cryptobranchoidea as the angular and prearticular bones in their lower jaws are fused, their trunk ribs are bicapitate, and all members use internal fertilization. The female is fertilized by means of a spermatophore, a sperm-containing cap placed by the male in her cloaca. The sperm is stored in spermathecae on the roof of the cloaca until it is needed at the time of oviposition.
The northern two-lined salamander is a species of salamander in the family Plethodontidae found in Canada and the United States. Its natural habitats are temperate forests, temperate shrubland, rivers, intermittent rivers, freshwater marshes, freshwater springs, arable land, and urban areas. It is more water-oriented than the related northern redback salamander, and can often be found in and around water such as rain puddles, streams, swamps, and damp stream beds, whereas the northern redback tends to be found in damp ground, but usually not near open water.
The Junaluska salamander is a species of lungless salamander native to the south-eastern United States. It was first described by David M. Sever, Harold M. Dundee, and Charles D. Sullivan who found the species in the range from the Cheoah River, Santeetlah Creek, and Tululah Creek in Graham County of North Carolina. Adults of this species can be found near large, rocky streams and on rainy nights on roads in the areas specified. The salamander is characterized by brownish-yellow coloration with a series of small dots along the body and a robust build compared to the other salamanders in Eurycea. The Junaluska salamander's breeding habits tend to be in large streams where the eggs are laid and attached to the bottom of rocks in the streams where they are found. According to the overall conservation listing for IUCN, this species is listed as Vulnerable. Conservation acts are important in both North Carolina and Eastern Tennessee, since the population of this species in each state is so small.
The Blue Ridge two-lined salamander is a species of salamander in the family Plethodontidae, endemic to the United States. This species is found in the southern Appalachian Mountains, mostly south of Virginia. To the north is a similar salamander, Eurycea bislineata, or the northern two-lined salamander. Its genus, Eurycea contains 33 species and includes taxa that have either a metamorphic life cycle or larval-form paedomorphosis. In species that metamorphose, there can be within-and among-population variation in larval life-history characteristics, e.g., duration of the larval period and size at metamorphosis. Intraspecific geographic variation in species of Eurycea has been attributed to several factors: temperature, stream order and productivity of the larval habitat.
An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs externally, although there are exceptions. For many species in the animal kingdom, the male intromittent organ is a hallmark characteristic of internal fertilization.
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.
Stanley E. Trauth was born September 5, 1948, in St. Louis, Missouri, but moved to Arkansas as a child in 1955. He is an American herpetologist and professor of zoology and environmental studies at Arkansas State University. He is also the curator of the herpetological collection of the Arkansas State University Museum of Zoology.
Inez Whipple Wilder, born Inez Luanne Whipple, was an American herpetologist and anatomist, affiliated with Smith College from 1902 until her death. She made notable contributions to the study of fingerprints and the biology of salamanders.
The epididymis, which is a tube that connects a testicle to a vas deferens in the male reproductive system, evolved by retention of the mesonephric duct during regression and replacement of the mesonephros with the metanephric kidney. Similarly, during embryological involution of the paired mesonephric kidneys, each mesonephric duct is retained to become the epididymis, vas deferens, seminal vesicle and ejaculatory duct. In reptiles and birds both the testes and excurrent ducts occur in an intra-abdominal location (testicond). Primitive mammals, such as the monotremes (prototheria), also are testicond. Marsupial (metatheria) and placental (eutheria) mammals exhibit differing degrees of testicular descent into an extra-abdominal scrotum. In scrotal mammals the epididymis is attached to the testes in an extra-abdominal position where the cauda epididymis extends beyond the lowest extremity of the testis. Hence, the cauda epididymis is exposed to the coolest of temperatures compared to all other reproductive structures.
Aspidoscelis costatus, also known as the western Mexico whiptail, is a species of whiptail lizard endemic to Mexico, including Guerrero, Morelos, and Puebla in southern Mexico, as well as other Mexican states. Its range spans both temperate and tropical habitats, and even densely populated urban areas. Its common name, the Western Mexico Whiptail, can easily be confused with the Western Whiptail, which refers to a different lizard, Aspidoscelis tigris.
