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Salamander

life science Maturity 7-9 Next article →

Salamanders are a diverse group of amphibians within the order Urodela. This scientific name is derived from Ancient Greek and means "conspicuous tail."

Salamander head
Salamander head

While they often resemble small lizards, they are biologically distinct. They typically possess a cylindrical trunk, four limbs, and a long tail. Most species are found in the Holarctic realm. However, some live in the Neotropical realm. The highest level of salamander diversity is found in eastern North America, particularly in the Appalachian Mountains.

Salamander -QDB
Salamander -QDB

A defining characteristic of many salamanders is their skin. Their skin is thin and permeable, meaning substances can pass through it easily. This permeability allows the skin to serve as a respiratory membrane for breathing. To stay moist, many species have costal grooves. These are vertical depressions running along the sides of the body. They function by channeling water over the skin's surface.

Taricha granulosa (Rough-skinned newt)
Taricha granulosa (Rough-skinned newt)

Some species, like those in the family Salamandridae, lack these grooves. Most salamanders also undergo a periodic skin shedding process. This moulting is controlled by hormones from the pituitary and thyroid glands. The animal pushes its body through a gap in the old skin. Once the skin is shed, the salamander often eats it to recover nutrients.

Salamanders possess a remarkable biological ability called regeneration. They can regrow lost limbs and tails without any scarring.

Axolotl Portrait
Axolotl Portrait

This ability extends to vital organs, including the heart, jaw, and parts of the spinal cord. Because they can rebuild complex tissues perfectly, they are invaluable model organisms for scientific research. Researchers study these processes to find potential human medical applications. They hope to use this knowledge to treat brain and spinal cord injuries. They also aim to prevent harmful scarring during heart surgery recovery.

The physical diversity of salamanders is vast. They range from minute species to the Chinese giant salamander. The giant species can reach massive sizes and weights.

Cryptobranchus alleganiensis
Cryptobranchus alleganiensis

The largest salamanders belong to families such as the giant salamanders, sirens, Congo eels, and Proteidae. These large species are often obligate paedomorphs, meaning they remain in an aquatic larval state throughout their lives. In contrast, other species undergo full metamorphosis to become terrestrial adults. Some species live entirely in water, while others are entirely land-based. Even their limbs vary. Some species have reduced or absent hind limbs, giving them an eel-like appearance.

Sirenlacertina
Sirenlacertina

Salamanders use various specialized structures for movement and defense. Their feet are shaped by their specific habitats. Climbing species often have elongated, square-tipped toes. Tree-climbing species, such as those in the genus Bolitoglossa, have plate-like webbed feet. These feet use suction to adhere to smooth surfaces.

Biofluorescent patterns across salamander diversity and anatomy - 41598 2020 59528 Fig1
Biofluorescent patterns across salamander diversity and anatomy - 41598 2020 59528 Fig1

The tail also serves many roles. It can act as a counterbalance while running. In some species, the tail is prehensile, meaning it can grasp objects. The tail can also be autotomised, or dropped, as a defense against predators. Some species even use their tails to launch themselves into the air.

Sensory perception in salamanders is highly specialized. They lack a middle ear cavity, eardrum, and eustachian tube. Instead, they use an opercularis system to detect sound. This system uses two bones called ossicles: the columella and the operculum.

P anguinus-head1
P anguinus-head1

This system can detect low-frequency vibrations between 500 and 600 Hz. These vibrations may travel through the ground and be picked up by the forelimbs. For vision, many species are adapted for nocturnal life. They possess trichromatic color vision that extends into the ultraviolet range. This vision relies on three types of photoreceptors sensitive to specific light wavelengths.

Proteus anguinus Postojnska Jama Slovenija
Proteus anguinus Postojnska Jama Slovenija

Chemical communication is also essential for many species. Salamanders use olfaction, or smell, for territory maintenance and courtship. They have an olfactory epithelium in the nasal cavity for airborne odors. They also have vomeronasal organs to detect chemical cues like tastes.

US-CA-NevadaCity-NewtAmplexus
US-CA-NevadaCity-NewtAmplexus

In some species, males have mental glands on their chins. They press these against a female's nostrils during courtship rituals. Some species also use pheromones to attract mates or mark territory. Finally, some species use bright colors as a warning. The rough-skinned newt produces tetrodotoxin, a powerful neurotoxin. This bright coloration advertises their toxicity to potential predators.

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🖼️ Images & Media (33)
File:Salamandra lanzai13.jpg
Salamandra lanzai13.jpg
File:S lacertina USGS.jpg
S lacertina USGS.jpg
File:Taricha granulosa (Rough-skinned newt).JPG
Taricha granulosa (Rough-skinned newt).JPG
File:P anguinus-head1.jpg
P anguinus-head1.jpg
File:Biofluorescent patterns across salamander diversity and anatomy - 41598 2020 59528 Fig1.jpg
Biofluorescent patterns across salamander...
File:Salamander -QDB.JPG
Salamander -QDB.JPG
File:Levatores arcuum of Necturus maculosus.png
Levatores arcuum of Necturus maculosus.png
File:Salamander head.png
Salamander head.png
File:Salamander-olympus.jpg
Salamander-olympus.jpg
File:US-CA-NevadaCity-NewtAmplexus.jpg
US-CA-NevadaCity-NewtAmplexus.jpg
Embryonic development of a salamander,...
File:Axolotl Portrait.jpg
Axolotl Portrait.jpg

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