Whilst bones present a static view of extinct animals, fossil footprints are a direct record of the activity and motion of the track maker. Deep footprints are a particularly good record of foot motion. Such footprints rarely look like the feet that made them; the sediment being heavily disturbed by the foot motion. Because of this, such tracks are often overlooked or dismissed in preference for more foot‐like impressions. However, the deeper the foot penetrates the substrate, the more motion is captured in the sediment volume. We have used deep, penetrative, Jurassic dinosaur tracks which have been naturally split into layers, to reconstruct foot motions of animals living over 200 million years ago. We consider these reconstructions to be hypotheses of motion. To test these hypotheses, we use the Discrete Element Method, in which individual particles of substrate are simulated in response to a penetrating foot model. Simulations that produce virtual tracks morphologically similar to the fossils lend support to the motion being plausible, while simulations that result in very different final tracks serve to reject the hypothesis of motion and help generate a new hypothesis.

中文翻译：

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使用数字化和模拟从化石轨迹构造和检验恐龙脚部运动的假设

骨头呈现出灭绝动物的静态视线，而化石足迹则是跟踪器活动和运动的直接记录。深的足迹是脚运动的特别好记录。这样的脚印很少看起来像使它们成脚的脚。脚部运动严重干扰了沉积物。因此，通常会优先忽略或忽略此类轨道，以产生更多类似脚的印象。但是，脚越深地穿透底物，沉积物中的运动就越多。我们使用了深层的，穿透性的，侏罗纪的恐龙足迹，这些足迹已自然地分为几层，以重建生活在2亿年前的动物的脚部运动。我们认为这些重构是运动的假设。为了检验这些假设，我们使用离散元方法，其中，响应于穿透的脚模型，模拟了单个衬底的颗粒。产生在形态上与化石相似的虚拟轨迹的模拟为运动提供了有力支持，而导致最终轨迹截然不同的模拟则可以用来拒绝运动假设并有助于产生新的假设。