中生代分三个纪:三叠纪、侏罗纪和白垩纪,2.3亿年前起,至6500万年前止。恐龙大约出现在三叠纪的中晚期,侏罗纪和白垩纪时极为繁盛,但到白垩纪末突然在世界各地全部消失。因此,中生代常被人们称为“恐龙时代”或“爬行动物时代”。 The Mesozoic is divided into three disciplines: Triassic, Jurassic and Cretaceous, 230 million years ago, to 65 million years ago. The dinosaurs appeared in the middle and late Triassic, and were extremely prosperous in the Jurassic and Cretaceous periods, but suddenly disappeared in all parts of the world by the end of the Cretaceous. Therefore, the Mesozoic are often referred to as the “dinosaur era” or “reptile era.”