Index by Period
The approximately 165 million years from the emergence of dinosaurs on Earth to their extinction is geologically known as the "Mesozoic Era", and is divided into three periods: the "Triassic", "Jurassic", and "Cretaceous", in order from oldest to newest. With the breakup of the supercontinent Pangea and dramatic changes in climate and flora, the leading dinosaurs in each period changed significantly. Let's trace the evolutionary trajectory of the dinosaurs that prospered in each geological age.
The Triassic period (approx. 251.9 to 201.3 million years ago) was an era when all the continents were united into the supercontinent Pangea, and a dry climate spread inland. In the Late Triassic (around 230 million years ago), early small dinosaurs such as Eoraptor, Herrerasaurus, and Coelophysis appeared. Armed with hard-shelled eggs resistant to drying and an upright bipedal stance that did not hinder breathing, dinosaurs steadily expanded their habitats in a harsh environment.
Entering the Jurassic period (approx. 201.3 to 145 million years ago), the breakup of Pangea began, resulting in a warm and humid climate, and rich forests of ginkgos, conifers, and ferns covered the earth. Supported by abundant plant resources, giant sauropods such as Brachiosaurus, Diplodocus, and Apatosaurus reached their golden age. In addition, Allosaurus, which preyed on them, and Stegosaurus, with bone plates on its back, flourished, and in the late stage, Archaeopteryx, considered the first bird, took to the skies.
The Cretaceous period (approx. 145 to 66 million years ago) was an era when the separation of continents progressed further, accelerating unique evolution in each region, and flowering "angiosperms" newly flourished. In response to changes in plants, ornithopods with advanced chewing abilities (Iguanodon and Parasaurolophus), ceratopsians (Triceratops), and armored dinosaurs (Ankylosaurus) prospered greatly. Carnivorous dinosaurs such as Tyrannosaurus and Spinosaurus also underwent ultimate evolution, but due to a giant meteorite impact about 66 million years ago, all dinosaurs except birds met their end.