Living reptiles and their fossil relatives
The evolutionary history of the reptiles.
The first reptiles (Captorhinida) evolved from amphibians in the early Carboniferous. From these early reptiles arose the mammal-like reptiles, the tortoises, the sea-living reptiles and the eosuchians. The mammal-like reptiles (synapsids) are known from the middle Carboniferous. They were the most diverse group of reptiles in the Permian and the Triassic. At the end of the Triassic the mammals evolved from the mammal-like reptiles. The synapsids went extinct in the Jurassic.
Four groups of sea-living reptiles existed in the Mesozoic. The ichthyosaurs, the placodonts and the nothosaurs all appeared in the early Triassic. The ichthyosaurs also lived in the Jurassic and in the Cretaceous, together with the long necked plesiosaurs.
The eosuchians were already a distinct group in the middle Carboniferous, and the thecodonts, the lizards and the rhynchocephalians originated from this group. The lizards and the rhynchocephalians still live today. The thecodonts existed mostly in the Triassic, and the dinosaurs, crocodiles and the pterosaurs evolved from them in the middle Triassic.
The dinosaurs were the dominating group of land reptiles during the Jurassic and the Cretaceous. They are divided into two groups: Saurischia and Ornitischia. In the Jurassic the first birds evolved from one group of the saurischian dinosaurs. The pterosaurs were reptiles where the fore limbs developed into wings. They went extinct at the end of the Cretaceous. The crocodiles are the only extant reptiles that evolved from the thecodonts.
The lizards (Lacertilia) are known from the Permian. Towards the end of the Cretaceous they became more diverse. At the same time the snakes (Serpentes) evolved. Today the snakes are the most diverse group of reptiles.
The turtles (Chelonia) are known from the Triassic and have changed little until today. List of contents in the living reptiles and their fossil relatives
Publisert 18. mai 2011 16:00 - Sist endret 13. mai 2019 13:56