Stegosaurus, four feet back with vertical bone osteoporosis, tail has two great to stab of stegosaurus, live mainly in Jurassic and cretaceous, to early dinosaurs class is one of the first perish.

• 剑龙类，四足行走背部具有直立的骨板，尾部有骨质刺棒两对，剑龙类主要生活在侏罗纪到早白垩纪，是恐龙类最先灭亡的一个大类。