Evolution of tetrapods

Ichthyostega, from Ancient Greek ἰχθύς (ikthús), meaning "fish", and στέγη (stégē), meaning "roof", is an extinct genus of limbed tetrapodomorphs from the Late Devonian of what is now Greenland. It was among the earliest four-limbed vertebrates ever in the fossil record and was one of the first with weight-bearing adaptations for terrestrial locomotion. Ichthyostega possessed lungs and limbs that helped it navigate through shallow water in swamps. Although Ichthyostega is often labelled a 'tetrapod' because of its limbs and fingers, it evolved long before true crown group tetrapods and could m

Tiktaalik (; ) is a monospecific genus of extinct sarcopterygian (lobe-finned fish) from the late Devonian Period, about 375 Mya (million years ago), having many features similar to those of tetrapods (four-legged animals). Tiktaalik is estimated to have had a total length of on the basis of various specimens.

Rhipidistia, also known as Dipnotetrapodomorpha, is a clade of lobe-finned fishes which includes the tetrapods and lungfishes. Rhipidistia formerly referred to a subgroup of Sarcopterygii consisting of the Porolepiformes and Osteolepiformes, a definition that is now obsolete. However, as cladistic understanding of the vertebrates has improved over the last few decades, a monophyletic Rhipidistia is now understood to include the whole of Tetrapoda and the lungfishes.

Eotetrapodiformes is an unranked clade of tetrapodomorphs including the four-limbed vertebrates ("tetrapods" in the traditional sense) and their closest finned relatives, two groups of stem tetrapods called tristichopterids and elpistostegalids.

gap in the tetrapod fossil record

origin and diversification of snake venom through geologic time

evolution of four legged vertebrates and their derivatives

origin and diversification of reptiles through geologic time