Caudata

English: Salamanders, Newts.
Synonym: Urodela.
Genera: 760 species; 9 families.
Clades: Amphibia; Deuterostomia; Animals.ZoologyCaudata are characterized by a superficially 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.TaxonomyDisagreement exists between different authorities as to the definition of the terms "Caudata" and "Urodela". Some maintain that Urodela should be restricted to the crown group, with Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article.
The evolutionary relationships between the three main groups of amphibians (apodans, urodeles and anurans) is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, suggested that the first divergence between these three groups took place soon after they had branched from the lobe-finned fish in the Devonian (around 360 million years ago), and before the breakup of the supercontinent Pangaea. The briefness of this period, and the speed at which radiation took place, may help to account for the relative scarcity of amphibian fossils that appear to be closely related to lissamphibians. However, more recent studies have generally found more recent age for the basalmost divergence among lissamphibians.Clades•• Cryptobranchoidea
Cryptobranchidae
Hynobiidae
•• Salamandroidea
Ambystomatidae
Amphiumidae
Dicamptodontidae
Plethodontidae
Proteidae
Rhyacotritonidae
Salamandridae
•• Sirenoidea
Sirenidae