古生代末期的物种大灭绝掳走了世界上70%的生命物种。三叠纪经过近1000万年的时间才从这场大灾难中恢复过来。而到这个时期,幸存的爬行动物进化到了新的形态,包括兽孔目爬行动物,这是一类似哺乳的爬行动物,这些动物到了晚三叠纪都进化为真正意义上的哺乳类动物。这其中也包括海生爬行动物,诸如幻龙和鱼龙,以及最早期的会飞的翼龙,还有就是在2.3亿年前出现的地球上最早的恐龙。 The Great Paleozoic extinction killed 70% of the world's living species. The Triassic recovered from this catastrophe only after nearly 10 million years. By this time, the surviving reptiles evolved into new forms, including the reptiles of the order Mammalia, a suckling reptile that had evolved into real mammals during the Late Triassic. These include marine reptiles, such as hallucinations and ichthyosaurs, as well as the earliest flying pterosaurs, and the earliest dinosaurs on earth that emerged 230 million years ago.