Flight and flight control in short-tailed Pterosaurs

翼龙是一群中生代的飞行类原型龙，代表了第一批实现真正动力飞行的脊椎动物。虽然它们的整体外观在晚三叠世的出现和马斯特里赫特的灭绝之间变化不大，（白垩纪晚期），飞行器的大小和构造的改变对它们的生态和空气动力学性能产生了明显的影响。就大小而言，最小的翼龙类，无尾颌类和最大的阿兹达奇类，如羽蛇翼龙（Quetzalcoatlus northropi（LAWSON 1975）、Hatzegopterxyx（BUFFETAUT等2002，2003）的数量是相当大的。而像隐鳍线翅虫（Nemicolopterus crypticus）（WANG et al 2008）这样的物种，其翼展仅为~ 250 mm。北翼鸟的翼展至少有10米，使其与几架现代人造飞机相当，而碎片遗骸表明其他物种（如Hatzegopteryx）可能会变得更大。除了尺寸之外，在衍生的翼龙类中还发现了至少3种独立的肩带结构，与基础翼龙类的情况不同（FREY等，2003 a）。肢体结构的演变，以及它们相关的膜，形成了主要的和支持飞行的表面，这些动物在如此巨大的不同尺寸和各种环境条件下必须面对的空气动力学和气动弹性挑战尚未得到充分的研究。本项目旨在研究基础翼龙和衍生翼龙的空气动力学性能，从而提供一个研究这与以前的尝试不同，因为它考虑了代表各种大小和飞行构型的分类群。通过对关键标本的检查和新的分析技术（例如物理/计算机建模，FEA）的应用，这项工作将扩展到翼龙飞行力学的创新研究。我们期待着对短尾翼龙的起源和进化的深入了解，以及对这个问题的答案，为什么这个群体可以进化出如此广泛的飞行器官？它还寻求如何将这种变化与白垩纪末期食性的多样化和日益增加的反亲性相结合。最后，它的目的是调查所观察到的变化，从基础长尾，短颈类群的小尾巴，长颈pterodacalidae和文件的空气动力学意义，这一根本性的变化形态。空气动力学的影响可以被认为是一个更广泛的理论的一部分，是什么驱使翼龙和非翼龙之间的进化机制。

The pterosaurs, a group of flying Mesozoic archosauromorphs, represent the first vertebrates to have achieved true, powered flight. While their overall appearance changed little between their appearance in the late Triassic and their extinction in the Maastrictian (Late Cretaceous), alterations in both size and configuration of the flight apparatus would have had a clear impact on their ecology and aerodynamic performance.In terms of size the range between the smallest pterosaurs, the anurognathoids, and the largest azhdarchids, e.g. Quetzalcoatlus northropi (LAWSON 1975), Hatzegopterxyx (BUFFETAUT et al 2002, 2003), is substantial. While species such as Nemicolopterus crypticus (WANG et al 2008) had a wingspan of only ~250mm Q. northropi grew to at least 10m in span, making it comparable to several modern man-made aircraft, while fragmentary remains suggest that other species (e.g. Hatzegopteryx) could grow larger still. In addition to size at least 3 separate shoulder girdle configurations have been demonstrated in the derived pterodactyloids, differing from that of the basal pterosaurian condition (FREY et al. 2003a). The evolution of the limb configurations, and their associated membranes, that formed the main and supporting flight surfaces, has yet to be fully investigated with regards to the aerodynamic and aeroelastic challenges that these animals must have faced operating at such vastly different sizes and in a variety of environmental conditions.This project seeks to investigate the aerodynamic performance of basal and derived pterosaurs and thus provides a study that differs from previous attempts by considering taxa which represent both a wide range of size and flight configurations. Through an examination of key specimens and the application of new analytical techniques (e.g. Physical/computer modelling, FEA) this work will be extended into innovating research on pterosaur flight mechanics. We expect accompanying insights into the origins and evolution of short-tailed pterosaurs and an answer to the question, why this group could evolve such a wide range of flight apparatuses? It also seeks how such alterations can be coupled with the diversification of feeding habits and increasing gigantism towards the end of the Cretaceous Period. Finally it aims to investigate the observed change from basal long tailed, short necked taxa to the small tail, long necked pterodactyloids and document the aerodynamic significance of this fundamental change in morphology. Aerodynamic influences can then be considered as part of a wider theory on what drove the evolutionary mechanisms between pterodactyloid and non-pterodactyloid pterosaurs.