First dinosaurs

In the late Triassic, first dinosaurs appeared and soon became divided into the basic groups: reptile-pelvis dinosaurs (sauropods and theropods) and bird-pelvis dinosaurs.

At the end of the Triassic, first mammals also appeared; they had originated from synapsids. The first flying reptiles, pterosaurs, also came from the late Triassic.

The Cretaceous, along with the Jurassic, is calleda ˊthe age of reptilesˊ. Throughout the entire period, the seas were dominated by the plesiosaurs. In the early Cretaceous, ichthiosaurs were quite common, however, they died out at the end of the epoch. In the late Cretaceous, a newly-evolved group of marine lizards (mosasaurs) was dominating in the seas; the largest of them reached more the length of more than 20 m. Marine crocodiles, reaching the length of 17 m, and giant turtles, were also found there. The air was dominated by flying reptiles, especially pterodactyluses, the largest of which with the wingspan of maximum 12 m.

The land was dominated by dinosaurs. Particularly dynamic was the development of bird-pelvis dinosaurs, including the newly-evolved horned dinosaurs (np. the triceratops) and duck-billed dinosaurs, which formed the largest herds of dinosaurs (up to 10,000 specimens) and hatching colonies.

Giant sauropodes were living in that period, but they were less frequent than in the Jurassic. In the Cretaceous, a slow evolution of mammals was also taking place; first marsupials and eutheria were formed back then.