始祖鸟目（Archaeopterygiformes） 从已发现的标本可以清楚地看到始祖鸟具有羽毛；后足不是对趾型；腕掌骨和跗跖骨愈合；骨盘结构、锁骨、喙部、下颌关节方式以及眼等许多特征与鸟类相似。始祖鸟具槽生齿，有具尾椎的长尾；脊椎双凹型；前翅掌指骨游离并具爪；脑、胸骨、肋骨及后肢等特征又与爬行类接近。所以始祖鸟被认为是爬行动物与鸟类之间的中间环节。
这种反对是合理的，因为只有早期的兽脚亚目食肉恐龙的锁骨才被发现，但是现在已经发掘出了类似始祖鸟的叉骨的兽脚亚目食肉恐龙锁骨化石。
This objection was reasonable when only early theropod clavicles had been discovered, but fossilized theropod clavicles that look just like the wishbone of Archaeopteryx have now been unearthed.
可能已经是时候最终接受‘始祖鸟’只是又一只在侏罗纪时期飞来飞去的长有羽毛的像鸟类的小兽脚亚目食肉恐龙了。
Perhaps the time has come to finally accept that archaeopteryx was just another small, feathered, bird-like theropod fluttering around in the Jurassic.
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