有尾目目

有尾目动物有发展完全的前肢和后肢，大小大约一致，但四肢细弱，少数种类仅有前肢（鳗螈）。眼小，或隐于皮下（洞螈），没有鼓膜或外耳开口。牙齿位于下颌。脊柱和肢骨纤细薄弱，肋骨退化，不足以支撑胸腔。身体有黏膜皮肤，没有鳞片或尖锐的爪子。通常行体内受精。

分类

• 有尾目包括：
• †蛙蜥螈科 Batrachosauroididae
• †科 Scapherpetontidae
• 隐鳃鲵亚目 Cryptobranchoidea
• 隐鳃鲵科 Cryptobranchidae
• 小鲵科 Hynobiidae
• 蝾螈亚目 Salamandroidea
• 钝口螈科 Ambystomatidae
• 两栖鲵科 Amphiumidae
• 陆巨螈科 Dicamptodontidae
• 无肺螈科 Plethodontidae
• 洞螈科 Proteidae
• 急流螈科 Rhyacotritonidae
• 蝾螈科 Salamandridae
• 鳗螈科 Sirenidae

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, the sole surviving order from the group Caudata. Urodela is a scientific Latin term based on the Ancient Greek οὐρά δήλη (ourà dēlē), "conspicuous tail". Caudata is the Latin for "tailed ones", from cauda, "tail".

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. 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.

This group of amphibians is capable of regenerating lost limbs as well as other damaged parts of their bodies. Researchers seek to reverse engineer the regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or preventing harmful scarring during heart surgery recovery. The salamander's ability to regenerate is not limited to limbs but extends to vital organs such as the heart, jaw, and parts of the spinal cord, contrasting most other vertebrates. ⁤⁤This ability is special in that it occurs without any type of scarring. ⁤⁤This has made salamanders a widespread model organism in scientific research aimed at understanding and achieving regenerative processes for medical advancements in human and animal biology.

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; 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. Some species in harsh environments reproduce while still in the Salamander larval state.