Operational Direction 'Earth and History of Life', Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000 Bruxelles, Belgium.
Nature. 2013 Jun 20;498(7454):359-62. doi: 10.1038/nature12168. Epub 2013 May 29.
The recent discovery of small paravian theropod dinosaurs with well-preserved feathers in the Middle-Late Jurassic Tiaojishan Formation of Liaoning Province (northeastern China) has challenged the pivotal position of Archaeopteryx, regarded from its discovery to be the most basal bird. Removing Archaeopteryx from the base of Avialae to nest within Deinonychosauria implies that typical bird flight, powered by the forelimbs only, either evolved at least twice, or was subsequently lost or modified in some deinonychosaurians. Here we describe the complete skeleton of a new paravian from the Tiaojishan Formation of Liaoning Province, China. Including this new taxon in a comprehensive phylogenetic analysis for basal Paraves does the following: (1) it recovers it as the basal-most avialan; (2) it confirms the avialan status of Archaeopteryx; (3) it places Troodontidae as the sister-group to Avialae; (4) it supports a single origin of powered flight within Paraves; and (5) it implies that the early diversification of Paraves and Avialae took place in the Middle-Late Jurassic period.
最近在中国东北辽宁省中晚侏罗世的髫髻山组发现了保存完好羽毛的小型兽脚亚目恐龙，这挑战了始祖鸟的核心地位，因为始祖鸟从发现以来一直被认为是最基础的鸟类。将始祖鸟从虚骨龙类的基础位置移到恐爪龙类内部，意味着仅由前肢驱动的典型鸟类飞行至少进化了两次，或者在某些恐爪龙类中随后丢失或修改。在这里，我们描述了来自中国辽宁省髫髻山组的一个新兽脚亚目恐龙的完整骨架。将这个新分类群纳入基础兽脚亚目恐龙的综合系统发育分析中，可以得出以下结果：（1）它将其恢复为最基础的虚骨龙类；（2）它证实了始祖鸟的虚骨龙类地位；（3）它将驰龙科置于鸟兽脚亚目恐龙的姐妹群；（4）它支持了在兽脚亚目恐龙中只有一次动力飞行的起源；（5）它表明，虚骨龙类和鸟兽脚亚目恐龙的早期多样化发生在中晚侏罗世时期。
