Reconstructing Theropod Dinosaur Limb Movements Using 3-D Computer-Animated Track Simulation

9974424 Gatesy兽脚亚目恐龙的后肢由17个相连的节段组成，在运动过程中进行周期性运动。这种形态、空间和时间的复杂性非常适合3-D动画工具，它允许模型随着时间的推移而自由地操纵位置的变化。然而，重建已灭绝的中生代兽脚亚目恐龙的肢体功能一直是个问题，因为几乎没有肢体偏移的直接证据。该项目将调查一系列独特的晚三叠世轨道，这些轨道是由兽脚类动物下沉到不同深度制成的。柔软的基底拦截了通常在空气中发生的足部运动，从而保存了兽脚类动物运动行为的三维记录。将使用三种计算机技术。(1)使用高分辨率X射线CT扫描对脚趾的三维路径进行可视化。(2)使用三维动画轨迹模拟重建足部运动。(3)使用重建的足部运动建模整个肢体运动。这种新方法将首次重建2.1亿年前兽脚亚目恐龙的行走路径和肢体运动。这些结论，来自脚印，而不是骨骼，将提供独立的证据来检验假设的兽脚亚目功能进化。以计算机为基础的方法将提供一个例子，说明图形和动画如何有助于复杂古生物材料的量化、分析和交流。

9974424 GatesyThe hind limb of a theropod dinosaur is composed of seventeen linked segments that undergo cyclical movements during locomotion. This morphological, spatial, and temporal complexity is well suited to the tools of 3-D animation, which permit a models change in position through time to be freely manipulated. However, reconstructing limb function in extinct Mesozoic theropods has been problematic, because little direct evidence of limb excursion is available. This project will investigate a unique series of Late Triassic trackways, which were made by theropods sinking to variable depth. Soft substrates intercepted foot movements that would normally occur in air, thereby preserving 3-D records of theropod locomotor behavior. Three computer techniques will be used. (1) Visualization of the 3-D pathway of the toes using high resolution X-ray CT scanning. (2) Reconstruction of foot movement using 3-D animated track simulation. (3) Modeling of whole limb movements using reconstructed foot movements. This novel approach will allow the foot path and limb movements of 210 million year old theropods to be reconstructed for the first time. These conclusions, derived from footprints rather than skeletons, will provide independent evidence to test hypotheses of theropod functional evolution. The computer-based methodology will offer an example of how graphics and animation can contribute to the quantification, analysis, and communication of complex paleontological material.