The precise definition of "tetrapod" is a subject of strong debate among paleontologists who work with the earliest members … See more

Tetrapoda includes three living classes: amphibians, reptiles, and mammals. Overall, the biodiversity of lissamphibians, as well as of tetrapods generally, has grown exponentially over time; the more than 30,00… See more

The classification of tetrapods has a long history. Traditionally, tetrapods are divided into four classes based on gross anatomical and physiological traits. Snakes and other legless reptiles are considered tetrapods because th… See more

Tetrapods evolved from early bony fishes (Osteichthyes), specifically from the tetrapodomorph branch of lobe-finned fishes (Sarcopterygii), living in the early to middle Devonian period.
The first tet… See more

The oldest evidence for the existence of tetrapods comes from trace fossils: tracks (footprints) and trackways found in Zachełmie, Poland, dated to the Eifelian stage of the Middle Devonian, 390 million years ago, although th… See more

Stem tetrapods are all animals more closely related to tetrapods than to lungfish, but excluding the tetrapod crown group. The cladogram below illustrates the relationships of stem-tetrapods. All these lineages ar… See more

The tetrapod's ancestral fish, tetrapodomorph, possessed similar traits to those inherited by the early tetrapods, including internal nostrils and a large fleshy fin built on bones that could give rise to the tetrapod li… See more