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Salamandridae

Salamandridae is a family of salamanders consisting of true salamanders and newts. Salamandrids are distinguished from other salamanders by the lack of rib or costal grooves along the sides of their bodies and by their rough skin. Their skin is very granular because of the number of poison glands. They also lack nasolabial grooves. Most species of Salamandridae have moveable eyelids but lack lacrimal glands.

Nearly all salamandrids produce a potent toxin in their skin, with some species being deadly to many other animal species. With a few exceptions, salamandrids have patterns of bright and contrasting colours, most of these are to warn potential predators of their toxicity. They have four well-developed limbs, with four toes on the fore limbs, and (in most cases) five toes on the hind limbs. They vary from in length.

Many species within this family reproduce by method of internal fertilization. Additionally, there are many species-specific courtship rituals that males perform to attract mates. These courtship rituals often employ pheromones to induce mating behavior in females. Pheromones have been discovered to be the driving force behind female mating responses in Alpine newts. These pheromones can induce behavior even when male visual epigamic characters and courtship dances are absent. All species within the genus Lyciasalamandra are viviparous, meaning they give birth to live young, without a tadpole stage. There are some species within the genus Salamandra are known to be viviparous too. Some newts are neotenic, being able to reproduce before they are fully metamorphosed. The females of many species can store sperm for up to 6 months at a time.

Toxicity

The genus Taricha use the poison tetrodotoxin (TTX) that binds and blocks voltage-gated sodium channels (Na<sub>v</sub>) in nerves and muscles. This blockage causes the cessation of action potentials, leading to paralysis and death. The rough-skinned newt (Taricha granulosa) uses tetrodotoxin and is considered the most poisonous species of newt. There are species and sub-species of Taricha that live in concurrent regions with a garter snake (Thamnophis) that has developed a resistance to the TTX poisoning. Species that inhabit regions with resistant Thamnophis snakes have evolved to increase their concentrations of TTX in an evolutionary arms race of predator versus prey.

Conservation status (IUCN Redlist)

Phylogeny

Cladograms based on the work of Pyron and Wiens (2011) and modified using Mikko Haaramo

Taxonomy

The genus Salamandrina is the only member of the subfamily Salamandrininae, and the genera Chioglossa, Lyciasalamandra, Mertensiella, and Salamandra are grouped in the subfamily Salamandrinae, with sixteen other genera comprising the subfamily Pleurodelinae. Those with a more thoroughly aquatic lifestyle are referred to as "newts", but this is not a formal taxonomic description.

Family SALAMANDRIDAE

Fossil record

Salamandrids have a substantial fossil record spanning most of the Cenozoic. The oldest known fossils date from the Thanetian (Paleocene), but these, and most other known fossil salamandrids apparently belong to the crown group. The sole known stem-salamandrid is Phosphotriton sigei, from the Quercy Phosphorites Formation, which apparently dates from the Middle to Late Eocene.

References

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