The Lissamphibia is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia, the Caudata, and the Gymnophiona.
Lissamphibia
Reconstruction of Gerobatrachus, possible ancestor of salamanders and frogs
A tetrapod is any four-limbed vertebrate animal of the superclass Tetrapoda. Tetrapods include all extant and extinct amphibians and amniotes, with the latter in turn evolving into two major clades, the sauropsids and synapsids. Some tetrapods such as snakes, legless lizards, and caecilians have evolved to become limbless via mutations of the Hox gene, although some do still have a pair of vestigial spurs that are remnants of the hindlimbs.
Tetrapod
Eusthenopteron, ≈385 Ma
Tiktaalik, ≈375 Ma
Acanthostega, ≈365 Ma