1] Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK [2] Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.
Nat Commun. 2013;4:2489. doi: 10.1038/ncomms3489.
Understanding the aerodynamic performance of feathered, non-avialan dinosaurs is critical to reconstructing the evolution of bird flight. Here we show that the Early Cretaceous five-winged paravian Microraptor is most stable when gliding at high-lift coefficients (low lift/drag ratios). Wind tunnel experiments and flight simulations show that sustaining a high-lift coefficient at the expense of high drag would have been the most efficient strategy for Microraptor when gliding from, and between, low elevations. Analyses also demonstrate that anatomically plausible changes in wing configuration and leg position would have made little difference to aerodynamic performance. Significant to the evolution of flight, we show that Microraptor did not require a sophisticated, 'modern' wing morphology to undertake effective glides. This is congruent with the fossil record and also with the hypothesis that symmetric 'flight' feathers first evolved in dinosaurs for non-aerodynamic functions, later being adapted to form lifting surfaces.
了解有羽恐龙的空气动力学性能对于重建鸟类飞行的进化至关重要。在这里，我们表明，当处于高升力系数（低升阻比）滑翔时，早白垩世的五翼手龙类小盗龙最为稳定。风洞实验和飞行模拟表明，对于小盗龙来说，从低海拔处滑翔以及在低海拔处之间滑翔时，以牺牲高阻力为代价维持高升力系数将是最有效的策略。分析还表明，在翼配置和腿部位置方面进行解剖上合理的改变对空气动力学性能的影响不大。对飞行的进化意义重大的是，我们表明，小盗龙不需要复杂的、“现代”的翼形态来进行有效的滑翔。这与化石记录以及对称“飞行”羽毛首先在恐龙中为非空气动力学功能进化，后来被适应形成升力面的假说一致。
