The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex.
The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex.
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DOI：
10.1038/s41598-017-02161-w
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发表时间：
2017-05-17
影响因子：
4.6
通讯作者：
Erickson GM
中科院分区：
文献类型：
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作者：
Gignac PM;Erickson GM
大多数食肉哺乳动物可以通过在咬合的牙齿之间产生超过皮质骨剪切强度的牙齿压力来粉碎骨骼成分，从而允许进入骨髓和磷酸盐。相反，食肉爬行动物有不咬合的牙列，在进食过程中对骨骼的损伤可以忽略不计。因此，大多数爬虫类掠食者只能吃掉整个骨头。然而，北美的暴龙，包括巨大的（13米[m]）兽脚亚目恐龙雷克斯暴龙（Tyrannosaurus rex）因习惯深深地咬入骨头，粉碎并消化它们而脱颖而出。在没有牙齿遮挡的情况下，这种类似哺乳动物的能力是如何形成的尚不清楚。在这里，我们从痕量证据中分析了霸王龙的摄食行为，估计了咬合力和牙齿压力，并研究了牙骨接触来提供答案。研究表明，骨粉碎性是通过以下因素的结合而实现的：(1)巨大的咬合力（8,526-34,522牛顿[N]）和牙齿压力（718-2,974兆帕斯卡[MPa]）促进骨骼中的裂纹扩展，(2)牙齿形状和牙弓结构集中了剪切应力，(3)重复的局部咬合。总的来说，这些能力和行为使霸王龙能够很好地撕碎骨头，并更充分地利用大型恐龙的尸体作为食物，而不是竞争的食肉动物。
Most carnivorous mammals can pulverize skeletal elements by generating tooth pressures between occluding teeth that exceed cortical bone shear strength, thereby permitting access to marrow and phosphatic salts. Conversely, carnivorous reptiles have non-occluding dentitions that engender negligible bone damage during feeding. As a result, most reptilian predators can only consume bones in their entirety. Nevertheless, North American tyrannosaurids, including the giant (13 metres [m]) theropod dinosaur Tyrannosaurus rex stand out for habitually biting deeply into bones, pulverizing and digesting them. How this mammal-like capacity was possible, absent dental occlusion, is unknown. Here we analyzed T. rex feeding behaviour from trace evidence, estimated bite forces and tooth pressures, and studied tooth-bone contacts to provide the answer. We show that bone pulverization was made possible through a combination of: (1) prodigious bite forces (8,526–34,522 newtons [N]) and tooth pressures (718–2,974 megapascals [MPa]) promoting crack propagation in bones, (2) tooth form and dental arcade configurations that concentrated shear stresses, and (3) repetitive, localized biting. Collectively, these capacities and behaviors allowed T. rex to finely fragment bones and more fully exploit large dinosaur carcasses for sustenance relative to competing carnivores.