美国耶鲁大学Armita R. Manafzadeh课题组在最新研究中，揭示了腓骨缩小与兽脚亚目动物运动的进化关系。该研究成果发表在2024年11月20日出版的《自然》上。

据了解，自二十世纪中期提出汉斯经典发育理论至今，鸟类腓骨的缩小一直引发着人们的好奇 。在恐龙进化过程中，腓骨从柱状结构转变为鸟类的劈状结构，长期以来人们一直认为这种变化对生物力学影响不大。

研究人员将三维运动学比较分析与化石记录中的过渡形态相结合，驳斥了腓骨对生物力学影响不大的假设，并证明退化的腓骨在实现膝关节长轴极限旋转（LAR）方面起着至关重要的作用。极度膝长轴旋转是鸟类运动的基本要素，活体鸟类经常利用它来执行复杂的陆地运动。

研究推断，在这种能力进化之前，早期兽脚类恐龙的膝关节运动受限于铰链状运动，这是由胫骨中部关节起源所驱动的，它排除了胫腓骨运动的祖先模式。

后来，将腓骨从踝关节中解放出来，使这一最初静止的关节得以活动，从而建立了一种新的胫腓骨运动学模式，这种模式对于现代鸟类保持极高的LAR水平至关重要。因此，腓骨缩小开启了向以LAR为主导的三维肢体控制过渡，这大大改变了兽脚类运动的进化进程。

附：英文原文

Title: Fibular reduction and the evolution of theropod locomotion

Author: Manafzadeh, Armita R., Gatesy, Stephen M., Nyakatura, John A., Bhullar, Bhart-Anjan S.

Issue&Volume: 2024-11-20

Abstract: Since Hampé’s classic developmental experiments in the mid-twentieth century1,2, the reduced avian fibula has sparked sustained curiosity3,4,5,6. The fibula transformed throughout dinosaur evolution from a columnar structure into its splint-like avian form, a change long thought to be of little biomechanical consequence3,6. Here we integrated comparative three-dimensional kinematic analyses with transitional morphologies from the fossil record to refute this assumption and show that the reduced fibula serves a crucial function in enabling extreme knee long-axis rotation (LAR). Extreme LAR is fundamental to avian locomotion and is regularly exploited by living birds to execute complex terrestrial manoeuvres7. We infer that the evolution of this capacity was preceded by restriction of the knee to hinge-like motion in early theropod dinosaurs, driven by the origin of a mid-shank articulation8 that precluded ancestral patterns of tibiofibular motion. Freeing of the fibula from the ankle joint later enabled mobilization of this initially static articulation and, in doing so, established a novel pattern of tibiofibular kinematics essential to the extreme levels of LAR retained by modern birds. Fibular reduction thus ushered in a transition to LAR-dominated three-dimensional limb control, profoundly altering the course of theropod locomotor evolution.

DOI: 10.1038/s41586-024-08251-w

Source: https://www.nature.com/articles/s41586-024-08251-w