反鸟类是繁盛于中生代的鸟类类群,它们在鸟类演化史上第一次成功地实现了全球性辐射,化石发现于除极地以外的各大陆白垩纪地层中,目前全世界被命名的反鸟类1属种超过了50个,其中我国辽西早白垩世“热河生物群”被命名的反鸟类新属种占总数的一半以上。最新的研究表明,在白垩期早期反鸟类的个体大小和相对翼长已有很大的分化,肩带和前肢上与飞行相关的骨骼特征已与现代鸟类基本相似,进步程度甚至高于同时期的今鸟类,表明适应飞行的演化已达到了很高的水平;吻部和牙齿的改变也较同时期的今鸟类多样,说明在食性也有了大的分异。新的发现也进一步减少了反鸟类和今鸟类——这两个中生代进步鸟类姊妹群之间的特征差异。 Anti-birds are flourishing in the Mesozoic bird groups, which in the history of bird evolution for the first time successfully global radiation, fossils found in the continent except the polar Cretaceous strata, the world is now named anti- More than 50 species of avian species have been identified, of which more than half of the new anti-bird species are named in the Early Cretaceous “Rehe Biota” in western Liaoning. Recent studies have shown that in the early Cretaceous period, individual size and relative wing length of anti-birds have greatly diverged, and flight-related skeletal features on shoulder straps and forelimbs have been similar to those of modern birds even higher than The current birds of the same period indicate that the evolution of adaptation flight has reached a very high level. Changes in snout and teeth are also more diverse than those of the present-day birds, indicating that there is also a big difference in food habits. New findings have further reduced the differences in features between anti-bird and present-day birds - the sister group of the two Mesozoic progressive birds.