The Evolution of Auditory Adaptations for Aquatic Life in Pinnipeds

鳍足类（海豹、海狮和海象）是海洋生态系统中的主要顶级捕食者，它们有着惊人的适应能力：在空中和水下都能听到声音。这种两栖听觉能力在哺乳动物中是独一无二的，是它们从陆地到水下生活进化的结果。鳍足类两栖动物的听觉之所以成为可能，是因为它们耳朵里有一个叫做海绵窦的器官，这导致了鳍足类动物在进化过程中对骨质耳朵的各种适应。鳍足类的生物声学是最近许多研究的主题。然而，这些研究都没有与他们的听觉解剖学联系起来，这几乎没有被探索过。在这个项目中，我将通过以下方式探索鳍足动物高度专业化的听觉解剖学的演变：（1）数字化和可视化鳍足动物的骨性耳区（包括活着的和灭绝的）和他们的近亲（2）回顾与水下听觉相关的鳍足类听觉适应的多样性;（3）通过三维几何形态测量学定量分析鳍足类内耳结构;（4）确定鳍足类之间听觉超声波能力的趋同进化;（5）通过系统发育比较方法研究鳍足类两栖听觉的起源。该项目将产生最全面的鳍足类骨性耳解剖的3D数字数据集。该项目将在鳍足动物的形态学和生物声学研究之间建立基础联系，为他们独特的两栖听觉进化提供深刻的见解。在这个项目中，我将获得3D几何形态测量学和系统发育比较方法的专业知识，以及开放科学实践，指导，教学，自然历史收藏管理和其他可转移技能的经验，这些技能将大大改善我未来的职业前景，坚定地确立我作为一名独立研究人员的地位。

Pinnipeds (seals, sea lions, and walruses) are key top predators of marine ecosystems that share a remarkable adaptation: the ability to hear in-air and underwater. This amphibious hearing ability, unique in mammals, is a result of their evolutionary transition from land to life underwater. Pinniped amphibious hearing is possible thanks to an organ in their ear called the cavernous sinus, which led to a diverse array of adaptations in the bony ear of pinnipeds during their evolution. The bioacoustics of pinnipeds has been the subject of many recent studies. However, none of this research has been linked to their auditory anatomy, which has barely been explored. In this project I will explore the evolution of the highly specialised auditory anatomy of pinnipeds by: (1) digitising and visualising the bony ear regions of pinnipeds (both living and extinct) and their close relatives (ursids and mustelids) via high-resolution micro-CT scanning; (2) reviewing the diversity of auditory adaptations in pinnipeds linked to underwater hearing; (3) quantitatively analysing pinniped inner ears via 3D geometric morphometrics; (4) identifying convergent evolution among pinnipeds towards the ability to hear ultrasonic sounds; (5) investigating the origin of amphibious hearing in pinnipeds using phylogenetic comparative methods. This project will result in the most comprehensive 3D digital dataset of the bony ear anatomy of pinnipeds. This project will establish a foundational link between morphological and bioacoustic studies in pinnipeds, providing profound insights into how their unique amphibious hearing evolved. During this project I will gain expertise in 3D geometric morphometrics and phylogenetic comparative methods, and experience in open science practices, mentorship, teaching, natural history collection management, and other transferable skills that will substantially improve my future career prospects, firmly establishing me as an independent researcher.