Rates of dinosaur limb evolution provide evidence for exceptional radiation in Mesozoic birds
Rates of dinosaur limb evolution provide evidence for exceptional radiation in Mesozoic birds
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DOI：
10.1098/rspb.2013.1780
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发表时间：
2013-10-07
影响因子：
4.7
通讯作者：
Choiniere, Jonah N.
中科院分区：
文献类型：
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作者：
Benson, Roger B. J.;Choiniere, Jonah N.
鸟类是最多样化的四足动物群体，是大规模适应性辐射的典范。新生物学研究表明，在飞行起源很久之后，冠状群内的辐射。然而，鸟类进化的深时间模式仍然模糊，因为只有有限的化石数据被认为是。我们分析了整个中生代兽脚类恐龙树的分支和肢体进化，记录了恐龙-鸟类的过渡和动力飞行的直接起源。中生代鸟类继承了限制前肢进化从非飞行的祖先，物种多样化的速度并没有加速在最早的飞行类群。然而，早白垩世短尾鸟类表现出后肢的表型释放和多样化率的增加，在兽脚类动物进化的前1.55亿年中的任何其他时间都是无与伦比的。因此，白垩纪的适应辐射的干组鸟类的地面运动模块，这是一个关键的创新重组。我们的研究结果表明，在Avialae辐射两个阶段：与白垩纪的多样化覆盖的干组鸟类在古近纪的边界，以及随后的多样化的冠组。我们的发现说明了化石数据对于理解产生现代生物多样性的宏观进化过程的重要性。
Birds are the most diverse living tetrapod group and are a model of large-scale adaptive radiation. Neontological studies suggest a radiation within the avian crown group, long after the origin of flight. However, deep time patterns of bird evolution remain obscure because only limited fossil data have been considered. We analyse cladogenesis and limb evolution on the entire tree of Mesozoic theropods, documenting the dinosaur-bird transition and immediate origins of powered flight. Mesozoic birds inherited constraints on forelimb evolution from non-flying ancestors, and species diversification rates did not accelerate in the earliest flying taxa. However, Early Cretaceous short-tailed birds exhibit both phenotypic release of the hind-limb and increased diversification rates, unparalleled in magnitude at any other time in the first 155 Myr of theropod evolution. Thus, a Cretaceous adaptive radiation of stem-group birds was enabled by restructuring of the terrestrial locomotor module, which represents a key innovation. Our results suggest two phases of radiation in Avialae: with the Cretaceous diversification overwritten by extinctions of stem-group birds at the Cretaceous-Palaeogene boundary, and subsequent diversification of the crown group. Our findings illustrate the importance of fossil data for understanding the macroevolutionary processes generating modern biodiversity.