Doctoral Dissertation Improvement: The Functional Anatomy of Prehensile and Nonprehensile Tails: Internal Architecture of Caudal Vertebrae and Musculature

博士论文改进：可抓握和不可抓握尾巴的功能解剖学：尾椎和肌肉组织的内部结构

• 批准号: 0550676
• 负责人: Mark Teaford
• 金额: $ 1.2万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-15 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0550676&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Improvement; Functional; Anatomy

Graduate student Jason Organ, under the supervision of Dr. Mark Teaford, will examine differences in bones and muscles of the tail among mammals that use their tails differently. Prehensile tails, ones that can fully suspend the body weight of the animal, are thought to have evolved independently at least 14 times among extant mammals, and probably twice (in parallel) in New World monkeys. Yet, despite the functional significance of tail prehension for balance, locomotion, and feeding, the mechanical structure of prehensile tails, and how this structure differs in nonprehensile tails, is not well understood. This study will examine the functional anatomy of prehensile and nonprehensile tails of New World monkeys and procyonids, a group of carnivoran mammals including coatis and kinkajous. Analyses will focus on (1) the cross-sectional geometric structure of caudal vertebrae (i.e., bone strength and rigidity) using computed tomography and (2) the internal structural properties of flexor compartment muscles using muscle fiber architectural analysis. Differences in bone and muscle properties, appropriately scaled for size differences, will be compared between species and different regions of the tail, and correlated with behavioral use of the tail during locomotion. Within both primates and procyonids, certain tail vertebrae of prehensile-tailed animals are predicted to be stronger and more rigid in bending and torsion when compared to nonprehensile-tailed animals. Differences in muscle internal architecture among groups are also expected, with certain muscles (the lateral flexors of the prehensile tail) predicted to be best structured to maximize force output, while other muscles (the ventral flexors) are predicted to be best suited for highly modulated control of the prehensile tail. Funding from the National Science Foundation will permit data collection from primate and procyonid skeletal and soft-tissue specimens at the Smithsonian National Museum of Natural History and the Department of Anatomical Sciences, Stony Brook University. Data collected will be used to address broader mechanical and evolutionary issues such as (1) the functional implications of muscle fiber architecture to energetic cost-efficiency, (2) how muscle architectural properties affect bone structure, (3) parallel evolution of tail prehensility within New World monkeys and among primates and procyonids, and (4) more accurate behavioral reconstructions of fossil prehensile-tailed mammals. The broader implications of this project include a strengthening of institutional ties between Johns Hopkins University School of Medicine and both the Smithsonian National Museum of Natural History and the Department of Anatomical Sciences at Stony Brook University. Furthermore, all material generated by this project will be donated to the Smithsonian National Museum of Natural History for future researchers, and all data will be published in a series of manuscripts and meeting abstracts, ultimately providing support for the training and professional development of the graduate student co-investigator. Finally, this study will represent the first comprehensive evaluation of both tail skeletal and muscular properties in primates and procyonids with prehensile and nonprehensile tails, and will be the first true test of morphologic similarity during the parallel evolution of tail prehensility in mammals.

研究生Jason Organ在Mark Teaford博士的指导下，将研究不同使用尾巴的哺乳动物尾巴骨骼和肌肉的差异。可缠绕的尾巴可以完全悬挂动物的体重，被认为在现存的哺乳动物中至少独立进化了14次，在新大陆猴子中可能进化了两次(平行)。然而，尽管抓住尾巴对平衡、运动和进食具有重要的功能意义，但抓住尾巴的机械结构，以及这种结构在不抓住尾巴中的不同之处，还没有被很好地理解。这项研究将研究新大陆猴子和原附着体的可缠绕和不可缠绕的尾巴的功能解剖学。原附着体是一组肉食性哺乳动物，包括Coatis和kinkajous。分析将集中在(1)使用计算机断层扫描的尾椎的横截面几何结构(即骨强度和硬度)和(2)使用肌肉纤维结构分析的屈肌的内部结构特性。骨骼和肌肉特性的差异将在物种和尾巴的不同区域之间进行比较，并与运动过程中尾巴的行为使用相关联。在灵长类和原附着体动物中，预计与非缠尾动物相比，可缠尾动物的某些尾椎在弯曲和扭转方面更强壮和更坚硬。预计不同群体的肌肉内部结构也会有所不同，预计某些肌肉(可缠绕尾巴的外侧屈肌)的结构最好，以最大化力量输出，而其他肌肉(腹侧屈肌)预计最适合高度调节控制可缠绕的尾巴。来自国家科学基金会的资金将允许在史密森国家自然历史博物馆和石溪大学解剖科学系收集灵长类和原鲤科动物骨骼和软组织标本的数据。收集的数据将用于解决更广泛的机械和进化问题，如(1)肌肉纤维结构对能量成本效益的功能影响，(2)肌肉结构特性如何影响骨骼结构，(3)新大陆猴子以及灵长类和原粘连蛋白之间尾巴紧张性的平行进化，以及(4)更准确的化石缠尾哺乳动物的行为重建。该项目的广泛影响包括加强约翰·霍普金斯大学医学院与史密森国家自然历史博物馆和石溪大学解剖科学系之间的机构联系。此外，该项目产生的所有材料将捐赠给史密森国家自然历史博物馆，供未来的研究人员使用，所有数据将以一系列手稿和会议摘要发表，最终为研究生合作调查员的培训和专业发展提供支持。最后，这项研究将首次全面评估灵长类和具有可缠绕和不可缠绕尾巴的原附着体的尾部骨骼和肌肉特性，并将首次在哺乳动物尾部缠绕能力的平行进化过程中对形态相似性进行真正的检验。