1、Archosaurs are a group of reptiles that includes crocodiles, birds, and their extinct relatives. 主龙类是包括鳄鱼、鸟类和它们已灭绝的亲戚在内的一类爬行动物。
2、During the Mesozoic Era, archosaurs were dominant and diverse in both terrestrial and aquatic environments. 在中生代时期，主龙类在陆地和水生环境中占主导地位且种类繁多。