Innovations in foraging behavior can drive morphological diversity by opening up new ways of interacting with the environment, or limit diversity through functional constraints associated with different foraging behaviors. Several classic examples of adaptive radiations in birds show increased variation in ecologically relevant traits. However, these cases primarily focus on geographically narrow adaptive radiations, consider only morphological evolution without a biomechanical approach, or do not investigate tradeoffs with other non‐focal traits that might be affected by use of different foraging habitats. Here, we use X‐ray microcomputed tomography, biomechanical modeling, and multivariate comparative methods to explore the interplay between foraging behavior and cranial morphology in kingfishers, a global radiation of birds with variable beaks and foraging behaviors, including the archetypal plunge‐dive into water. Our results quantify covariation between the shape of the outer keratin covering (rhamphotheca) and the inner skeletal core of the beak, as well as highlight distinct patterns of morphospace occupation for different foraging behaviors and considerable rate variation among these skull regions. We anticipate these findings will have implications for inferring beak shapes in fossil taxa and inform biomimetic design of novel impact‐reducing structures.

中文翻译：

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跳水鸟类的形态创新和生物力学多样性

觅食行为的创新可以通过开辟与环境相互作用的新方式来推动形态多样性，或者通过与不同觅食行为相关的功能限制来限制多样性。鸟类适应性辐射的几个经典例子显示生态相关性状的变化增加。然而，这些案例主要关注地理范围狭窄的适应性辐射，只考虑形态进化而没有生物力学方法，或者不研究可能受使用不同觅食栖息地影响的其他非焦点特征的权衡。在这里，我们使用 X 射线显微计算机断层扫描、生物力学建模和多变量比较方法来探索翠鸟觅食行为与颅骨形态之间的相互作用，具有可变喙和觅食行为的鸟类的全球辐射，包括原型潜入水中。我们的结果量化了外角蛋白覆盖物（rhamphotheca）的形状和喙的内骨骼核心之间的协变，并突出了不同觅食行为的不同形态空间占据模式和这些头骨区域之间相当大的速率变化。我们预计这些发现将对推断化石类群中的喙形状产生影响，并为新型减振结构的仿生设计提供信息。以及突出不同觅食行为的不同形态空间占用模式和这些头骨区域之间的相当大的速率变化。我们预计这些发现将对推断化石类群中的喙形状产生影响，并为新型减振结构的仿生设计提供信息。以及突出不同觅食行为的不同形态空间占用模式和这些头骨区域之间的相当大的速率变化。我们预计这些发现将对推断化石类群中的喙形状产生影响，并为新型减振结构的仿生设计提供信息。