The Ear Regions of Archosaurs: The Transition to the Modern Avian and Crocodilian Conditions and Functional Implications for Hearing and Balance in Dinosaurs

始祖龙的耳朵区域：向现代鸟类和鳄鱼条件的转变及其对听觉和平衡的功能影响俄亥俄大学劳伦斯·M·维特默俄亥俄大学耳朵区域是头部的一个复杂区域，涉及两个基本功能，听力和平衡感(平衡)。这个项目研究了始祖龙(包括今天的鸟类和鳄鱼，以及中生代的恐龙、翼龙和其他灭绝形式的动物)的内耳、中耳和外耳的解剖结构。总体目标是结合生活在今天和遥远过去的动物的信息，记录耳朵的进化变化，一方面帮助我们了解现代条件是如何在现有鸟类和鳄鱼的祖先中产生的，另一方面，提供对恐龙等化石群体的行为、感觉生物学和生态的洞察。然而，化石只保留了坚硬的部分(骨骼和牙齿)，因此该项目的一个关键要素是重建灭绝的原始龙耳朵区域的软组织成分，这将为功能解释提供基础。关于耳部软组织的假说将在现有的系统发育支架(EPB)方法的背景下进行测试，根据该方法，化石群(恐龙)的现代近亲(鸟类、鳄鱼、蜥蜴)提供关于软组织与它们在骨骼上留下的特征之间关系的信息。现代动物的相关软组织(内耳迷路、气窦、鼓膜)将通过解剖、注射、组织学和放射学成像等方法进行研究，以发现软组织在骨上的特征。然后，将对始祖龙化石进行调查，以了解这些特定的骨骼特征。对数十个关键化石标本进行CT扫描将是一个关键工具，因为它不仅将提供有关颅骨内嵌入的特征(内耳、气窦)的数据，还将产生3D数字数据集，从中可以自动进行高精度的测量。所研究的一些特定的耳朵系统包括(1)内耳道，因为它们与活动性和敏捷性广泛相关，它们的方向允许重建首选的头部姿势；(2)内耳的耳蜗管，因为它关系到广泛的听力表现；以及(3)中耳和外耳，包括鼓膜、气窦和传声装置，因为它们与耳朵的声学特性有关，并最终与听力有关。这项研究将影响多个领域。许多本科生和研究生将接受技术和分析培训。该项目是高度合作的，涉及世界各地的许多古生物学家和实验学家。广泛的放射成像将需要开发精细的成像协议、标准化的分析、专门的工作站和生物信息学创新来处理海量的多格式数字数据。不仅传播数据而且操纵数据的基于互联网的手段将是必不可少的，并将与现有的生物信息学中心联系起来进行。鉴于K-12对所有恐龙的持续兴趣，这个项目将吸引人们的注意，这将提供新的机会，利用恐龙作为工具来教授一般的科学知识，预计的场所是媒体、学校或其他公开露面，以及互联网。

The Ear Regions of Archosaurs:the Transition to the Modern Avian and Crocodilian Conditions and Functional Implications for Hearing and Balance in DinosaursLawrence M. WitmerOhio UniversityThe ear region is a complex area of the head that is concerned with two fundamental functions, hearing and the sense of balance (equilibrium). This project examines the anatomical organization of inner, middle, and outer ears of archosaurs (the group of animals including birds and crocodilians today, and dinosaurs, pterodactyls, and other extinct forms in the Mesozoic Era). The overarching goal is to combine information from animals living today and in the distant past to document the evolutionary changes in the ear that, on the one hand, help us understand how the modern condition arose in ancestors of existing birds and crocodilians, and, on the other hand, provide insight into the behavior, sensory biology, and ecology of fossil groups like dinosaurs. Fossils, however, preserve only hard parts (bones and teeth), and thus a key element of the project is to reconstruct the soft-tissue components of the ear regions of extinct archosaurs, which will then provide a basis for functional interpretation. Hypotheses about the soft tissues in the ear region will be tested in the context of the extant phylogenetic bracket (EPB) approach, whereby the modern relatives (birds, crocodilians, lizards) of the fossil group (dinosaurs) provide information on the relationship between soft tissues and the signatures they leave on the bones. Pertinent soft tissues (inner ear labyrinth, air sinuses, ear drum) will be studied in the modern animals using methods such as dissection, injection, histology, and radiologic imaging to discover the signatures of the soft tissues on bone. Fossil archosaurs will then be surveyed for these specified bony features. CT scanning of literally dozens of pivotal fossil specimens will be a critical tool in that it will not only provide data on features embedded within the skull (inner ear, air sinuses) but also will yield 3D digital datasets from which highly accurate measurements can be made automatically. Some of the specific ear systems studied include (1) the inner ear canals because they are broadly correlated with activity and agility, and their orientation allows reconstruction of preferred head postures; (2) the cochlear duct of the inner ear because it has bearing on broad categories of hearing performance; and (3) the middle and outer ear, including the ear drum, air sinuses, and sound conducting apparatus because they relate to acoustic properties of the ear, and ultimately hearing. This study will impact a number of areas. Numerous undergraduate and graduate students will receive technical and analytical training. The project is highly collaborative, involving many paleontologists and experimentalists worldwide. The extensive radiologic imaging will require development of refined imaging protocols, standardized analyses, specialized workstations, and bioinformatics innovations to deal with the voluminous multi-format digital data. Internet-based means of not only disseminating the data but also manipulating the data will be essential, and will take place in connection with existing bioinformatics hubs. Given the continual K-12 interest in all things dinosaurian, the attention this project will attract will provide new opportunities to use dinosaurs as tools to teach about science in general, with expected venues being media outlets, school or other public appearances, and the internet.