Salamander Life Cycles
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Salamander life cycles Continue SALAMANDER LIFE CYCLE This is a blue spotted salamander. Its life cycle is the same as most salamanders. Click the image to follow the lifecycle. When you return to this page, you can see the lifecycle again or go elsewhere. Order of amphibians (Urodela) For the mythical lizard, Salamanders see in folklore. For other uses, see Salamander (disambiguation). SalamandersTemporal range: Late Jurassic – Present Day,[1] 160-0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Salamander, Ambystoma maculatum Scientific Classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Amphibian Clade: Caudata Order: UrodelaDuméril, 1806 Suborders Cryptobranchoidea Salamandroidea Native distribution of salamanders (in green) Salamanders is a group of amphibians typically characterized by a lizard-like appearance , with slender bodies, blunt muzzers, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All modern salamander families are grouped together under the order Urodela. Salamander diversity is highest in the northern hemisphere and most species are found in the Holarctic realm, with some species found in the neotropical sphere. Salamanders rarely have more than four toes on the forelimbs and five on their hind legs, but some species have fewer numbers and others lack hind legs. Their permeable skin usually makes them dependent on habitats in or near water or other cool, moist places. Some salamander species are completely aquatic throughout life, some make their way to the water periodically, and others are completely terrestrial as adults. They can recreate lost limbs, as well as other damaged parts of their bodies. The researchers hope to reverse engineer the remarkable regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or prevent harmful scarring during cardiac surgery recovery. [2] Members of the Salamandridae family are best known as newts and lack the costal traces along the sides of their bodies that are typical of other groups. The skin of some species contains the powerful poison tetrodotoxin; these salamanders tend to be slow and have bright warning staining to advertise their toxicity. Salamanders usually lay eggs in water and have aquatic larvae, but great variation occurs in their life cycles. Some species in harsh environments reproduce while they are still in larval state. Description X-ray of salamander Skin lacks scales and is moist and smooth to the touch, except in newts of Salamandridae, which may have velvety or variesome skin, wet to the touch. The skin can be gray or colorful, exhibiting different patterns of stripes, bars, spots, spots, or dots. Male newts become dramatically colored during the breeding season. Cave species living in the dark lack pigmentation and have a pink or pearlescent appearance. [3] Salamanders range in size from minute salamanders, with a total length of 2.7 cm (1.1 in), including tail, to the Chinese giant salamander reaching 1.8 m (5.9 feet) and weighing up to 65 kg (143 lb). However, most are between 10 and 20 cm (3.9 and 7.9 in) in length. [4] Trunk, limbs and tail An adult salamander generally resembles a small lizard, which has a basal tetrapod body shape with a cylindrical trunk, four limbs, and a long tail. Except in the family Salamandridae, the head, body and tail have a number of vertical depressions in the surface that run from the middle of the dorsal region to the ventral area and are called costal grooves. Their function seems to be to help keep the skin moist by channeling water across the surface of the body. [5] Sirens have an eel- like appearance. Some aquatic species, such as sirens and amphiumas, have decreased or absent hind legs, giving them an eel-like appearance, but in most species, the anterior and posterior limbs are about the same length and project sideways, barely raising the trunk from the ground. The feet are wide with short numbers, usually four on the front feet and five on the back. Salamanders have no claws, and the shape of the foot varies depending on the animal's habitat. Climbing species have elongated, square toes, while mountain-dwellers have larger feet with short, blunt toes. The tree-climbing salamander (Bolitoglossa sp.) has flat-like webbed feet that follow smooth surfaces by suction, while rock climbing Hydromantes species from California have feet with fleshy scaffolding and short numbers and use their tails as an extra limb. Upon ascent, the tail props up the back of the body, while one hind foot moves forward and then swings to the other side to provide support as the other backfoot advances. [6] In larvae and aquatic salamanders, the tail is flattened sideways, its dorsal and ventral fins and undulates have side to side to push the animal through the water. In the Ambystomatidae and Salamandridae families, the male's tail, which is larger than the female's, is used under amplexus embrace to drive the mating pair to a secluded place. In terrestrial species, the tail goes to counterbalance the animal as it runs, while in arboreal salamander and other tree climbing species, it's prehensile. The tail is also used by some plethodontid salamanders that can jump, to help launch themselves into the air. [6] The tail is used in courtship and as a storage organ for proteins and lipids. It also serves as a defense against predation, when it can be lashed at the attacker or autotomised when seized. Unlike frogs, an adult salamander can regenerate limbs and its tail when these are lost. [6] Skin Rough-skinned newt Skin of salamanders, in common with other amphibians, is thin, permeable to water, services a respiratory membrane, and is well supplied with glands. It has highly cornified outer layers, renewed periodically by a skin shedding process controlled by hormones from the pituitary gland and thyroid gland. During moulting, the skin initially breaks around the mouth, and the animal moves forward through the gap to discard the skin. When the front limbs have worked clearly, a series of body ripples push the skin towards the back. The hind legs are extracted and push the skin further back, before it is eventually released by friction as the salamander moves forward with its tail pressed to the ground. [7] The animal often eats the resulting sloughed skin. [3] Glands in the skin discharge mucus that keeps the skin moist, an important factor in skin breathing and thermoregulation. The sticky layer helps protect against bacterial infections and molds, reduces friction during swimming, and makes the animal slippery and harder for predators to catch. Granular glands scattered on the upper surface, especially the head, back, and tail, produce repellent or toxic secretions. [7] Some salamander toxins are particularly potent. The rough-skinned newt (Taricha granulosa) produces neurotoxin tetrodotoxin, the most toxic nonprotein substance known. Handling newts does no harm, but ingestion of even one minute fragments of the skin is fatal. In feeding trials, fish, frogs, reptiles, birds and mammals were all found to be susceptible. [8] Mature adults of some salamander species have wedding glandular tissue in their kloacae, at the base of the tail, on the head or under the chin. Some females release chemical substances, possibly from the ventral sewage gland, to attract males, but males do not seem to use pheromones for this purpose. [9] In some plethodonts, males have conspicuous mental glands on their chins pressed against the nostrils of females during the courtship ritual. They can work to speed up the mating process, reducing the risk of it being disturbed by a predator or a rival male. [10] The gland at the tail base in Plethodon cinereus is used to mark fecal pellets to proclaim territorial ownership. [9] Senses The anterior part of olm's head carries sensitive chemo, mechano, and electroreceptors. Olfaction in salamanders plays a role in territory maintenance, recognition of predators, and courtship rituals, but is probably secondary to sight during prey selection and feeding. Salamanders have two types of sensory areas that respond to the chemistry of the environment. Olfactory epithelium in the nasal cavity picks up airborne and aquatic odors, while adjacent vomeronasal bodies detect nonvolatile chemical clues, such as flavors in the mouth. In plethodonts, the sensory epithelium of vomeronasal organs extends to the nasolabial grooves, ranging from the nostrils to the tongues of the mouth. Extended areas appear to be associated with identification of prey objects, recognition of conspecifics, and identification of individuals. [11] Most salamanders' eyes are primarily adapted to the sight of the night. In some permanent aquatic species, they are reduced in size and have a simplified retinal structure, and in cave inhabitants like Georgia blind salamander, they are absent or covered with a layer of skin. In amphibian species, the eyes are a compromise and are nearsighted in air and farsighted in water. Completely terrestrial species like the fire salamander have a flatter lens that can focus over a much wider distance. [12] To find their prey, salamanders use trichromatic color vision that extends into ultraviolet ranges, based on three photoreceptor types that are maximally sensitive around 450, 500, and 570 nm. [13] The larvae, and the adults of some very aquatic species, also have a lateral line organ, similar to that of fish, which can detect changes in water pressure. [3] All salamanders lack the middle ear cavity, eardrum and eustachian tube, but have an opercularis system like frogs, and can still detect airborne sound. [14] [15] The opercularis system consists of two ossicles: the columellan (corresponding to the stapes of higher vertebrates) fixed to the skull and the operculum.