McCurry M R, Walmsley C W, Fitzgerald E M G, McHenry C R
Monash Biomedicine Discovery Institute and Centre for Human Anatomy Education, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia; Geosciences, Museums Victoria, Melbourne, Australia; Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA; School of Biological Sciences, Monash University, Melbourne, Australia.
Monash Biomedicine Discovery Institute and Centre for Human Anatomy Education, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.
J Biomech. 2017 May 3;56:61-70. doi: 10.1016/j.jbiomech.2017.03.003. Epub 2017 Mar 21.
Unrelated clades of aquatic tetrapod have evolved a similar range of skull shapes, varying from longirostrine (elongate and narrow rostrum) to brevirostrine (short rostrum). However, it is unclear which aspects of organismal performance are associated with this convergence in the range of skull shapes. Furthermore, it is not known how fundamental anatomical differences between groups influence these relationships. Here we address this by examining the load bearing capabilities of the skulls of two of the most diverse groups of living aquatic tetrapod: crocodilians and odontocetes. We use finite element analysis to examine the abilities of different cranial morphologies to resist a range of biologically relevant feeding loads including biting, shaking and twisting. The results allow for form/function relationships to be compared and contrasted between the two groups. We find that cranial shape has similar influences on performance during biting, shaking or twisting load cases at the anterior tooth positions, e.g. brevirostrine species experienced less strain than longirostrine species. The pattern of this form/function relationship is similar for both crocodilians and odontocetes, despite their fundamentally different anatomies. However, when loading teeth at the posterior end or middle of the tooth row the results do not follow the same pattern. Behavioural differences in bite location plays a key role in determining functional abilities in aquatic tetrapod taxa.
水生四足动物的不同进化分支已经演化出了相似范围的头骨形状，从长吻型（长而窄的吻部）到短吻型（短吻部）各不相同。然而，尚不清楚生物体性能的哪些方面与这种头骨形状范围的趋同现象相关联。此外，也不清楚不同类群之间的基本解剖学差异如何影响这些关系。在此，我们通过研究现存最多样化的两类水生四足动物——鳄鱼和齿鲸——的头骨承重能力来解决这个问题。我们使用有限元分析来研究不同颅骨形态抵抗一系列与生物学相关的进食负荷的能力，包括咬、摇晃和扭转。这些结果使得能够对两组之间的形态/功能关系进行比较和对比。我们发现，在前牙位置，无论是咬、摇晃还是扭转负荷情况下，颅骨形状对性能的影响相似，例如，短吻型物种比长吻型物种承受的应变更小。尽管鳄鱼和齿鲸的解剖结构存在根本差异，但这种形态/功能关系模式在两者中是相似的。然而，当在齿列后端或中间加载牙齿时，结果并不遵循相同的模式。咬的位置的行为差异在决定水生四足动物类群的功能能力方面起着关键作用。
