Dissertation Research: Understanding the Functional Ecomorphology of Extinct Canids During the Cat-Gap

物种多样性的下降每十年都更加明显。这种下降与当地和区域气候模式有关。了解相关动物群体如何适应新开放的社区生态位是一项挑战。然而，我们可以回顾过去，看看动物是如何适应物种群的消失的。这个项目旨在描述在500万年的时间跨度（2100万到1600万年前），当北美没有猫的时候，一般的狗（包括狐狸、狗、狼等）在解剖学和行为学上是如何反应的。这一时期被称为猫洞期。研究人员将利用3D扫描技术，包括小规模扫描，并使用各种3D软件，分析猫洞之前，期间和之后化石狗的前肢解剖结构。将与现代已知行为的狗和猫进行比较，以解释已灭绝的犬科动物的潜在行为。研究的主要目标是了解在北美没有猫的500万年里，某些犬科动物是否进化出了类似猫的适应性。该项目将为本科生提供通过参与研究的各个方面来学习研究的机会。此外，在当地九年级科学老师的帮助下，部分研究将被开发成为期三天的高中水平stem集成模块。研究人员将使用3D成像技术（NextEngine 3D扫描仪、纳米oct成像）开发一个现有和已灭绝的猫科动物和犬科动物的肱骨、桡骨和尺骨的表面图像数据库。这些3D表面图像随后将通过3D地标形态测量学进行分析，将它们的形态与中新世早期猫隙（21至16 Ma）之前，期间和之后的化石犬科动物的形态进行比较，并了解个体的形态适应与其捕食行为相关。初步数据表明，猫隙时期的犬科动物前肢形态属于猫科动物，而不属于现代犬科动物。研究人员将检验这一结论在“猫洞”前后是否成立，并假设只有在“猫洞”期间，犬科动物在形态上更像猫。本项目生成的3D数据将上传到MorphoSource供公众访问。

The decline of species diversity is more apparent each decade. This decline is correlated with local and regional climate patterns. Understanding how related groups of animals will adapt in response to newly open community niches is challenging. However, we can look to the past to see how animals adapted to the loss of taxa. This project aims to describe how dogs in general (including foxes, dogs, wolves, etc.) responded in their anatomy and behavior during a 5-million-year time span (21 to 16 million years ago) when there were no cats in North America. This time period is known as the Cat-Gap. Working with 3D scanning techniques, including scans at a tiny scale, and using various 3D software, the researchers will analyze the anatomy of the forelimb of fossil dogs before, during, and after the Cat-Gap. Comparisons will be made with modern dogs and cats of known behavior to make interpretations of the potential behavior of the extinct canids. The primary goal is to learn whether certain canids evolved cat-like adaptations during the 5 million years when North America had no cats. This project will provide undergraduate students with opportunities to learn about research through involvement in all aspects of the research. In addition, parts of the research will be developed into a three-day high school level STEM-integrated module with the help of a local ninth grade science teacher. The researchers will use 3D imagining techniques (NextEngine 3D scanners, nanoCT imaging) to develop a database of surface images for the humerus, radius, and ulna of extant and extinct felids and canids. These 3D surface images will then be analyzed through 3D landmark morphometrics to compare their morphology to that of fossil canids before, during, and after the early Miocene Cat-Gap (21 to 16 Ma), with an understanding that an individual's morphological adaptations are correlated with its predatory behavior. Preliminary data suggest that canids during the Cat-Gap fall within felids and outside of modern canids in their forelimb morphology. Researchers will examine if this holds true before and after the Cat-Gap, with the hypothesis that the canids were more cat-like in morphology only during the Cat-Gap. The 3D data generated by this project will be uploaded for public access in MorphoSource.