1] Staatliche Naturwissenschaftliche Sammlungen Bayerns, Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, 80333 Munich, Germany [2] Department of Earth and Environmental Sciences and GeoBioCenter, Ludwig-Maximilians-Universität München, Richard-Wagner-Straße 10, 80333 Munich, Germany.
Tannenweg 16, 85134 Stammham, Germany.
Nature. 2014 Jul 3;511(7507):79-82. doi: 10.1038/nature13467.
Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have helped to put the iconic 'Urvogel' Archaeopteryx into context and have yielded important new data on the origin and early evolution of feathers. However, the biological context under which pennaceous feathers evolved is still debated. Here we describe a new specimen of Archaeopteryx with extensive feather preservation, not only on the wings and tail, but also on the body and legs. The new specimen shows that the entire body was covered in pennaceous feathers, and that the hindlimbs had long, symmetrical feathers along the tibiotarsus but short feathers on the tarsometatarsus. Furthermore, the wing plumage demonstrates that several recent interpretations are problematic. An analysis of the phylogenetic distribution of pennaceous feathers on the tail, hindlimb and arms of advanced maniraptorans and basal avialans strongly indicates that these structures evolved in a functional context other than flight, most probably in relation to display, as suggested by some previous studies. Pennaceous feathers thus represented an exaptation and were later, in several lineages and following different patterns, recruited for aerodynamic functions. This indicates that the origin of flight in avialans was more complex than previously thought and might have involved several convergent achievements of aerial abilities.
近几十年来，鸟类兽脚亚目恐龙和基干鸟兽脚类恐龙的发现，有助于了解标志性的“始祖鸟”在何种背景下出现，并为羽毛的起源和早期演化提供了重要的新数据。然而，羽毛演化的生物学背景仍存在争议。本文描述了一件新的始祖鸟标本，其羽毛保存非常完整，不仅在翅膀和尾部，而且在身体和腿部也有羽毛。新标本表明，整个身体都覆盖着羽状羽毛，后肢胫骨上有长而对称的羽毛，但跗跖骨上的羽毛很短。此外，翼羽的形态表明，一些最近的解释存在问题。对先进的手盗龙类和基干鸟兽脚类的尾巴、后肢和前肢上的羽毛在系统发育上的分布进行分析，强烈表明这些结构的演化与飞行无关，而是出于展示等其他功能，这与一些先前的研究结果一致。因此，羽毛是一种适应，后来在几个谱系中，以不同的模式，被用于空气动力学功能。这表明，鸟兽脚类的飞行起源比以前认为的更为复杂，可能涉及到几种空中能力的趋同进化。
