Young Mark T, Rayfield Emily J, Holliday Casey M, Witmer Lawrence M, Button David J, Upchurch Paul, Barrett Paul M
School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK.
Naturwissenschaften. 2012 Aug;99(8):637-43. doi: 10.1007/s00114-012-0944-y. Epub 2012 Jul 12.
Sauropod dinosaurs were the largest terrestrial herbivores and pushed at the limits of vertebrate biomechanics and physiology. Sauropods exhibit high craniodental diversity in ecosystems where numerous species co-existed, leading to the hypothesis that this biodiversity is linked to niche subdivision driven by ecological specialisation. Here, we quantitatively investigate feeding behaviour hypotheses for the iconic sauropod Diplodocus. Biomechanical modelling, using finite element analysis, was used to examine the performance of the Diplodocus skull. Three feeding behaviours were modelled: muscle-driven static biting, branch stripping and bark stripping. The skull was found to be 'over engineered' for static biting, overall experiencing low stress with only the dentition enduring high stress. When branch stripping, the skull, similarly, is under low stress, with little appreciable difference between those models. When simulated for bark stripping, the skull experiences far greater stresses, especially in the teeth and at the jaw joint. Therefore, we refute the bark-stripping hypothesis, while the hypotheses of branch stripping and/or precision biting are both consistent with our findings, showing that branch stripping is a biomechanically plausible feeding behaviour for diplodocids. Interestingly, in all simulations, peak stress is observed in the premaxillary-maxillary 'lateral plates', supporting the hypothesis that these structures evolved to dissipate stress induced while feeding. These results lead us to conclude that the aberrant craniodental form of Diplodocus was adapted for food procurement rather than resisting high bite forces.
蜥脚类恐龙是地球上最大的陆地食草动物，它们突破了脊椎动物生物力学和生理学的极限。在众多物种共存的生态系统中，蜥脚类恐龙表现出高度的颅齿多样性，这引发了一种假说，即这种生物多样性与生态专业化驱动的生态位细分有关。在这里，我们定量研究了标志性蜥脚类恐龙梁龙的进食行为假说。我们使用有限元分析进行生物力学建模，以检验梁龙颅骨的性能。模拟了三种进食行为：肌肉驱动的静态咬食、树枝剥离和树皮剥离。研究发现，颅骨对于静态咬食来说“设计过度”，整体应力较低，只有牙齿承受高应力。在模拟树枝剥离时，颅骨同样承受低应力，这些模型之间几乎没有明显差异。当模拟树皮剥离时，颅骨承受的应力要大得多，尤其是在牙齿和颌关节处。因此，我们反驳了树皮剥离假说，而树枝剥离和/或精确咬食假说均与我们的研究结果一致，表明树枝剥离是梁龙科恐龙在生物力学上可行的进食行为。有趣的是，在所有模拟中，在上颌骨 - 上颌骨的“侧板”中观察到峰值应力，这支持了一种假说，即这些结构的进化是为了消散进食时产生的应力。这些结果使我们得出结论，梁龙异常的颅齿形态是为了获取食物，而非抵抗高咬合力。
