Foffa Davide, Cuff Andrew R, Sassoon Judyth, Rayfield Emily J, Mavrogordato Mark N, Benton Michael J
School of Earth Sciences, University of Bristol, Bristol, UK.
J Anat. 2014 Aug;225(2):209-19. doi: 10.1111/joa.12200. Epub 2014 Jun 13.
Pliosaurs were among the largest predators in Mesozoic seas, and yet their functional anatomy and feeding biomechanics are poorly understood. A new, well-preserved pliosaur from the Kimmeridgian of Weymouth Bay (UK) revealed cranial adaptations related to feeding. Digital modelling of computed tomography scans allowed reconstruction of missing, distorted regions of the skull and of the adductor musculature, which indicated high bite forces. Size-corrected beam theory modelling showed that the snout was poorly optimised against bending and torsional stresses compared with other aquatic and terrestrial predators, suggesting that pliosaurs did not twist or shake their prey during feeding and that seizing was better performed with post-symphyseal bites. Finite element analysis identified biting-induced stress patterns in both the rostrum and lower jaws, highlighting weak areas in the rostral maxillary-premaxillary contact and the caudal mandibular symphysis. A comparatively weak skull coupled with musculature that was able to produce high forces, is explained as a trade-off between agility, hydrodynamics and strength. In the Kimmeridgian ecosystem, we conclude that Late Jurassic pliosaurs were generalist predators at the top of the food chain, able to prey on reptiles and fishes up to half their own length.
上龙是中生代海洋中最大的食肉动物之一，然而它们的功能解剖学和捕食生物力学却鲜为人知。一个来自英国韦茅斯湾启莫里奇阶的保存完好的新上龙化石揭示了与捕食相关的颅骨适应性特征。通过对计算机断层扫描进行数字建模，可以重建头骨和内收肌组织中缺失或变形的区域，结果显示其咬合力很强。尺寸校正梁理论建模表明，与其他水生和陆生食肉动物相比，上龙的吻部在抵抗弯曲和扭转应力方面优化程度较低，这表明上龙在捕食过程中不会扭动或摇晃猎物，且在联合部后方咬食时更有利于抓捕猎物。有限元分析确定了吻部和下颌在咬食时产生的应力模式，突出了吻部上颌-前上颌接触处和下颌联合部尾部的薄弱区域。相对较弱的头骨与能够产生强大力量的肌肉组织并存，这被解释为是在敏捷性、流体动力学和力量之间进行权衡的结果。在启莫里奇阶生态系统中，我们得出结论，晚侏罗世的上龙是处于食物链顶端的广食性食肉动物，能够捕食长达自身长度一半的爬行动物和鱼类。
