[1] The oldest fossil "proto-frog" appeared in the early Triassic of Madagascar, but molecular clock dating suggests their origins may extend further back to the Permian, 265 million years ago.

The families Alytidae, Pipidae, and Pelobatidae are ecologically isolated, the harlequin frogs, restricted to a neotropical range in Central and South America, and the Ranidae and Bufonidae probably radiated from tropical regions of Africa and Asia.

[3] Another molecular phylogenetic analysis conducted about the same time concluded the lissamphibians first appeared about 330 million years ago and that the temnospondyl-origin hypothesis is more credible than other theories.

[5] A further study in 2011 using both extinct and living taxa sampled for morphological, as well as molecular data, came to the conclusion that the Lissamphibia are monophyletic and should be nested within the Lepospondyli rather than within the Temnospondyli.

It dated back 290 million years and was hailed as a missing link, a stem batrachian close to the common ancestor of frogs and salamanders, consistent with the widely accepted hypothesis that frogs and salamanders are more closely related to each other (forming a clade called the Batrachia) than they are to caecilians.

[10] The skull of Triadobatrachus is frog-like, being broad with large eye sockets, but the fossil has features diverging from modern frogs.

[10] The Salientia (Latin salere (salio), "to jump") are a stem group including modern frogs in the order Anura and their close fossil relatives the "proto-frogs" (e.g., Triadobatrachus and Czatkobatrachus).

The common features possessed by the "proto-frogs" in the Salientia group include 14 presacral vertebrae (modern frogs have eight or nine), a long and forward-sloping ilium in the pelvis, the presence of a frontoparietal bone, and a lower jaw without teeth.

[14] Salientia Caudata – Salamanders and newts Albanerpetontidae – Extinct Gymnophiona – Caecilians Cladogram from Tree of Life Web Project.