Craniodental functional evolution in sauropodomorph dinosaurs

Sauropodomorpha included the largest known terrestrial vertebrates and was the first dinosaur clade to achieve a global distribution. This success is associated with their early adoption of herbivory, and sauropod gigantism has been hypothesized to be a specialization for bulk feeding and obligate high-fiber herbivory. Here, we apply a combination of biomechanical character analysis and comparative phylogenetic methods with the aim of quantifying the evolutionary mechanics of the sauropodomorph feeding apparatus. We test for the role of convergence to common feeding function and divergence toward functional optima across sauropodomorph evolution, quantify the rate of evolution for functional characters, and test for coincident evolutionary rate shifts in craniodental functional characters and body mass. Results identify a functional shift toward increased cranial robustness, increased bite force, and the onset of static occlusion at the base of the Sauropoda, consistent with a shift tow...蜥脚形亚目（Sauropodomorpha）包含了目前已知体型最大的陆生脊椎动物，也是首个实现全球分布的恐龙演化支。这一演化成功与其早期的植食性适应性密切相关，针对蜥脚类巨型化（Sauropod gigantism），学界曾提出假说，认为其是适应批量取食与专性高纤维植食性的特化演化策略。本研究结合生物力学性状分析与比较系统发育方法，旨在定量解析蜥脚形亚目进食器官的演化力学机制。我们检验了蜥脚形亚目演化历程中趋同于共同进食功能、分化至功能最适点的演化模式，量化了功能性状的进化速率，并探究了颅齿功能性状与体质量是否存在同步的进化速率转变。研究结果显示，在蜥脚类（Sauropoda）的基部类群中，出现了颅部强健度提升、咬合力增强以及静态咬合首次出现的功能转变，这与向……的演化转变相一致。