Dinosaurs first evolved in the Triassic period. Though this was when dinosaurs first appeared, they were very different from the famous Tyrannosaurus rex. There were not only dinosaurs, but also another group of dinosaur-like reptiles called Archosaurs. Archosaurs ruled the lands before dinosaurs. Dinosaurs at the time of the Triassic looked pretty different. Dinosaurs were also considered rare. Most dinosaurs looked were small and slim-most not even ten feet long! It wasn't until the end of the Triassic where there was a mass extinction, then dinosaurs could finally rule earth! The earth at this time was still one continent called Pangaea or Pangea, so most of the dinosaurs were adapted to the same environments.
There were many different dinosaur that developed at this time. Here are some dinosaurs that developed in the Triassic period:
-The temperature was not very warm -The top predators were usually crocodiles or crocodile like creatures. - The Triassic period started 251 million years ago and ended roughly at 199 million years ago. - The Triassic period lasted about 52 million years -Many types of plant developed in the Triassic period, such as ferns. The first Ferns developed way back around 360 million years ago, but most species of fern you can still see today developed around 200-180 million years ago. - The planet was still one giant continent called Pangaea, or Pangea and the climate was very cold and dry.
Triassic life
At the end of the Permian period, which was the period before the Triassic, about 95% of ocean life was wiped out because of high levels of carbon dioxide. Since the Permian period ended, a new species of marine reptiles developed. First, there was the dolphin like Ichthyosaurs, which some grew to huge sizes! One type of Ichthyosaur called Shonisaurus grew at least up to 50 feet long! Other species of marine reptiles evolved around the Triassic too, such as the Plesiosaurs. Plesiosaurs were long necked marine reptiles that evolved during the Triassic period, but later thrived in the Jurassic period. One type of Triassic Plesiosaur can be Pistosaurus, which only grew up to feet long. Airborne reptiles called Pterosaurs developed too, like Dimorphodon, or Eudimorphodon. Early Pterosaurs were reletivley small and had a long tail and toothed jaws, unlike later Pterosaurs.