Palatal Biomechanics and Its Significance for Cranial Kinesis in Tyrannosaurus rex
Palatal Biomechanics and Its Significance for Cranial Kinesis in Tyrannosaurus rex
复制标题
DOI：
10.1002/ar.24219
复制
发表时间：
2019-07-18
影响因子：
2
通讯作者：
Holliday, Casey M.
中科院分区：
文献类型：
--
作者：
Cost, Ian N.;Middleton, Kevin M.;Holliday, Casey M.
已灭绝的非鸟类恐龙霸王龙雷克斯，被认为是有史以来最难咬的动物之一，经常被假设表现出颅运动，或颅关节相对于脑壳的活动性。T.雷克斯是一个生物力学悖论，因为强力撕咬的四足动物通常拥有坚硬的头骨，而不是带有活动关节的头骨。我们测试了一个暴龙头骨的生物力学性能，使用一系列的静态位置模仿可能的上颚偏移，以评估暴龙的姿势动力学能力。一个功能性的现存系统发育支架使用类群，表现出可测量的腭偏移：鹦鹉erithacus（前后运动）和壁虎（mediolateral运动）。静态有限元模型的鹦鹉，壁虎，和暴龙构建和测试不同的腭姿势使用解剖学上知情的材料属性，加载来自解剖，系统发育括号，肌肉结构和灵敏度分析的肌肉力量，并测试在正交咬合模拟使用元素应变作为代理模型性能。现存物种模型显示，与替代品相比，自然发生的姿势中的菌株较低。我们发现，前后和中性模型的暴龙经历了较低的整体应变比mediolatively转移模型。与下颌关节限制相比，伸肌抑制了腭部的应变，而枕骨限制增加了腭颅关节的应变。这些加载行为表明，即使是很小的偏移也会使元件应变超过结构失效。因此，这些运动的姿势测试，连同其他颅骨特征的强健性，沿着表明暴龙的头骨在功能上是运动不能的。Anat Rec，2019年。(c)2019 Wiley Periodicals，Inc.
The extinct nonavian dinosaur Tyrannosaurus rex, considered one of the hardest biting animals ever, is often hypothesized to have exhibited cranial kinesis, or, mobility of cranial joints relative to the braincase. Cranial kinesis in T. rex is a biomechanical paradox in that forcefully biting tetrapods usually possess rigid skulls instead of skulls with movable joints. We tested the biomechanical performance of a tyrannosaur skull using a series of static positions mimicking possible excursions of the palate to evaluate Postural Kinetic Competency in Tyrannosaurus. A functional extant phylogenetic bracket was employed using taxa, which exhibit measurable palatal excursions: Psittacus erithacus (fore-aft movement) and Gekko gecko (mediolateral movement). Static finite element models of Psittacus, Gekko, and Tyrannosaurus were constructed and tested with different palatal postures using anatomically informed material properties, loaded with muscle forces derived from dissection, phylogenetic bracketing, and a sensitivity analysis of muscle architecture and tested in orthal biting simulations using element strain as a proxy for model performance. Extant species models showed lower strains in naturally occurring postures compared to alternatives. We found that fore-aft and neutral models of Tyrannosaurus experienced lower overall strains than mediolaterally shifted models. Protractor muscles dampened palatal strains, while occipital constraints increased strains about palatocranial joints compared to jaw joint constraints. These loading behaviors suggest that even small excursions can strain elements beyond structural failure. Thus, these postural tests of kinesis, along with the robusticity of other cranial features, suggest that the skull of Tyrannosaurus was functionally akinetic. Anat Rec, 2019. (c) 2019 Wiley Periodicals, Inc.