无数长羽毛恐龙和早期鸟类的发现，让人们能够在更大的背景下来审视最早的鸟——“始祖鸟”。但这个类别的鸟仍然还有让人吃惊的地方。来自巴伐利亚的Solnhofen 石灰岩地层的一个新发现的材料(这仅仅是1861年以来发现的第11个材料或标本)显示，其全身都覆盖着大量羽毛。尤其值得注意的是，它的后腿上覆盖着像是羽毛“裤子”的东西。对该材料腿和尾上的羽毛分布所做的分析显示，有梗羽毛(我们所熟悉的现代鸟类身上的那种羽毛)很可能并不是为了飞行才形成的，它们也许是为了展示才形成的。封面照片：Helmut Tischlinger。
Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have helped to put the iconic ‘Urvogel’ Archaeopteryx1 into context2, 3, 4, 5, 6 and have yielded important new data on the origin and early evolution of feathers7. However, the biological context under which pennaceous feathers evolved is still debated. Here we describe a new specimen of Archaeopteryxwith 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 interpretations8, 9 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 studies10, 11, 12. 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.