The suborder Salamander is a more advanced type of amphibians, their fertilization methods are in vivo fertilization, some of which are viviparous or oviparous, some members remain in juvenile form for life, some of which are fetal or oviparous, and some members remain juvenile throughout their lives. The suborder Salamander is divided into the Eel Salamander family, amphibian salamander family, cave salamander family, blunt-mouthed salamander family, land salamander family, lungless salamander family and salamander family, which are mainly concentrated in North America.
The eel salamander is distributed in the southeastern United States and northeastern Mexico, where the large eel is nearly one meter long, the small eel is about 70 cm long, and the eel salamander is only 25 cm long. Eel salamanders are the most peculiar of the caudal order, with a slender body, no hind limbs, a long eel in appearance, a lifelong external gills, and possibly in vitro fertilization, of which the large eel salamander and the small eel have three pairs of gills, while the eel salamander has only a pair of gill cleavages and three fingers. Eel salamanders live all their lives in shallow, slow-moving water. Sometimes ashore, the body secretes mucus during drought to form a hard cocoon similar to that of the African lungfish.
Amphibian salamanders are large, lifelong aquatic salamanders with gills or gills, slender bodies that resemble eels, and are therefore known as Congolese eel salamanders, with tiny limbs that are not easily detected. The amphibian salamander family is found only in the southeastern United States.
The cave salamander is a lifelong aquatic salamander that remains juvenile and has an outer cheek. The body of the cave salamander is less than 30 cm long, and the body becomes black due to leaving the cave when exposed to the sun, and returns to the cave to a light color. The spotted salamander in the mud salamander can be more than 40 cm long, while the other 4 types of mud salamander are less than 28 cm long. It is found almost throughout North America from Alaska to Mexico. Some species of blunt-mouthed salamander live in the water throughout their lives while maintaining juvenile characteristics. Adults generally burrow underground and return to the water only during the breeding season.
It is endemic to the northwestern United States. The Apatosaurus burrows underground and returns to the water only during the breeding season. Some species also retain juvenile form for life.
Members of the pulmonary salamander family are completely lungless and can only breathe with skin. It is found mainly in southern North America. Members of the lungless salamander family are adapted to a variety of living environments, terrestrial? Aquatic, arboreal and burrowing are all represented, and the difference in body shape is also relatively large. Large salamanders such as Bailey are more than 30 cm long, and small salamanders such as Sorrie are less than 3 cm long.
The salamander family is a progressive member of the suborder Salamander, but is also a minority of ovulatory or oviparous births. There are many species of salamanders that have toxins , such as the red wart salamander , which is found in southwest China and neighboring Southeast Asia.