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

每隔十年，物种多样性的下降就更加明显。这一下降与当地和地区的气候模式有关。理解相关的动物群体将如何适应新开放的社区生态位是具有挑战性的。然而，我们可以回顾过去，看看动物如何适应类群的丧失。这个项目旨在描述一般的狗(包括狐狸、狗、狼等)。在北美没有猫的500万年(2100万到1600万年前)的时间跨度内，它们的解剖和行为做出了反应。这段时间被称为Cat-Gap。研究人员将使用3D扫描技术，包括微小规模的扫描，并使用各种3D软件，分析在Cat-Gap之前、期间和之后的狗化石前肢的解剖。将与已知行为的现代狗和猫进行比较，以解释灭绝的犬科动物的潜在行为。主要目标是了解在北美没有猫的500万年里，某些犬类是否进化出了类似猫的适应能力。这个项目将为本科生提供机会，通过参与研究的各个方面来了解研究。此外，部分研究将在当地一名九年级科学教师的帮助下，开发成为期三天的高中水平STEM综合模块。研究人员将使用3D成像技术(NextEngine 3D扫描仪、纳米CT成像)开发现存和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。然后，这些3D表面图像将通过3D地标形态计量学进行分析，以将它们的形态与早期中新世Cat-Gap(21至16 Ma)之前、期间和之后的犬类化石进行比较，了解到个体的形态适应与其捕食行为相关。初步数据表明，在猫科动物间隙中，犬类在前肢形态上属于猫科动物，而在现代犬科动物之外。研究人员将检验这一点在猫科动物间隙前后是否成立，假设犬类只有在猫科动物间隙期间才会在形态上更像猫。该项目生成的3D数据将被上传到MorPhoSource中供公众访问。

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.