An order of amphibians in which members retain a tail throughout their life cycle, have legs at right angles to the body, have fore and hind legs of aproximately equal size*, and teeth on both their jaws.

They appear throughout the world, but most species are found in North America. Most are aquatic or semi-aquatic. They are devided into two groups; those who are aquatic and keep their gills throughout life (due to paedomorphosis) are perrennibranchs, and those who lose their gills and move to land upon adulthood are caducibranchs.

Newts, Salamanders, axolotls, and mud puppies belong to this order.

The other orders of amphibians are the Salientia and the Apoda (AKA Gymnophiona or Ophiomorpha).

* One group, the sirens, have small forelimbs and no hindlimbs. They are sometimes placed in a seperate order, Trachystomata.