Los caudados (Caudata), conocidos como salamandras, son un clado de anfibios compuesto por 695 especies vivas que se distribuyen en los continentes del hemisferio norte con la excepción de unas pocas especies en el norte de Sudamérica. Un tercio de las salamandras conocidas habitan en Norteamérica. La concentración más alta se dan en la región de las montañas Apalaches. A diferencia de los anuros (ranas), poseen una cola bien desarrollada y carecen de oído medio. Los registros más antiguos de salamandras datan de mediados del período Jurásico (Batoniano), siendo la especie Chunerpeton tianyiensis el representante más antiguo de las salamandras modernas (Urodela). Los últimos estudios moleculares datan la divergencia con respecto a las ranas en el período Pérmico.

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Salamanders are a group of amphibians typically characterized by a 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 present-day salamander families are grouped together under the scientific name Urodela. Salamander diversity is most abundant in the Northern Hemisphere and most species are found in the Holarctic ecozone, with some species present in the Neotropical zone. Salamanders never have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to the water intermittently, and others are entirely terrestrial as adults. Unique among vertebrates, they are capable of regenerating lost limbs, as well as other damaged parts of their bodies. Members of the family Salamandridae are mostly known as newts and lack the costal grooves along the sides of their bodies typical of other groups. The skin of some species contains the powerful poison tetrodotoxin and these salamanders tend to be slow-moving and have bright warning coloration to advertise their toxicity. Salamanders typically lay eggs in water and have aquatic larvae, but great variation occurs in their lifecycles. In some species and some harsh environments, salamanders reproduce while still in the larval state. In literature and legend, the salamander is associated with fire, being supposedly unharmed by the flames, while clothes made from its skins or 'wool' were believed to be incombustible. More plausibly, salamanders were said to be intensely poisonous. Despite this, salamander brandy, a drink prepared by dunking live salamanders in fermenting fruit juices, is reputed to have hallucinogenic and aphrodisiac properties. The salamander's ability to regenerate lost body parts is being investigated and research is ongoing into any applications this may have for human medicine.

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