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

祖龙的耳区：向现代鸟类和鳄鱼条件的转变以及对恐龙听力和平衡的功能影响

• 批准号: 0343744
• 负责人: Lawrence Witmer
• 金额: --
• 依托单位: Ohio University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-15 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0343744&HistoricalAwards=false
• 关键词: Ear; Regions; Archosaurs; Transition; Modern

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.

原始龙的耳区：过渡到现代鸟类和鳄鱼的条件和功能的影响，为听力和平衡的恐龙。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）。这个项目研究了主龙（包括今天的鸟类和鳄鱼，以及恐龙，翼手龙和中生代其他灭绝形式的动物）的内耳，中耳和外耳的解剖组织。总体目标是将联合收割机的信息从现在和遥远的过去生活的动物中结合起来，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出现在现有鸟类和鳄鱼的祖先中的，另一方面，提供对恐龙等化石群体的行为，感觉生物学和生态学的见解。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已灭绝的祖龙耳朵区域的软组织成分，这将为功能解释提供基础。关于耳朵区域软组织的假设将在现存系统发育支架（EPB）方法的背景下进行测试，其中化石组（恐龙）的现代亲属（鸟类，鳄鱼，蜥蜴）提供了软组织和它们在骨骼上留下的签名之间的关系的信息。将使用解剖、注射、组织学和放射成像等方法在现代动物中研究相关软组织（内耳迷路、鼻窦、鼓膜），以发现骨上软组织的特征。然后将对这些特定的骨骼特征对化石祖龙进行调查。对数十个关键化石标本的CT扫描将是一个关键工具，因为它不仅可以提供嵌入头骨（内耳，空气窦）的特征数据，还可以产生3D数字数据集，从中可以自动进行高度精确的测量。研究的一些特定的耳系统包括：（1）内耳道，因为它们与活动和敏捷性广泛相关，并且它们的方向允许重建首选的头部姿势;（2）内耳的耳蜗管，因为它对听力性能的广泛类别有影响;以及（3）中耳和外耳，包括鼓膜、气窦和声音传导装置，因为它们涉及耳朵的声学特性，并最终涉及听力。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，以处理大量的多格式数字数据。基于互联网的手段不仅传播数据，而且还处理数据，这将是至关重要的，并将与现有的生物信息学中心联系起来。考虑到K-12对所有关于恐龙的事情的持续兴趣，这个项目将吸引的关注将提供新的机会，利用恐龙作为工具来教授一般的科学知识，预计场地是媒体，学校或其他公共场合，以及互联网。