Doctoral Dissertation Research: Identifying dental morphological variation among Pliocene hominins

本博士论文项目分析了420 - 300万年前人类牙齿化石中牙齿特征的大小和形状的变化。 在过去的几十年里，这种古老的牙齿化石的可用性显着增加，但这些发现中的许多都是孤立的牙齿，仍然无法归因于任何物种或属。 为了解决这个问题，博士生使用了一种新的方法，可以改进古人类牙齿的分类鉴定，并进一步了解这些人类物种之间的牙齿和形态学界限。 来自人类牙齿化石的信息没有被分配到一个物种，不能完全整合到古人类学分析，仍然没有得到充分利用。除了培训一名研究生外，该项目还包括培训本科生，沿着计划通过外联活动与公众分享成果，由此产生的3D扫描将在公共存储库中提供。该项目收集了所有已知上新世人类物种牙齿的公制，非公制和二维地标数据，可追溯到420万至300万年前。目标是评估来自该时期遗址的许多分类学上未归因的孤立牙齿的亲和力。每个比较物种的牙齿样本量大，可以进行有意义的观察，以确定每个分类群的离散牙齿特征或特征集。一旦确定，这些特征可以用于新发现的孤立牙齿的分类学鉴定。考虑到最近的假设上新世人类的多样性和南方古猿anamensis-Australopithecus afarensis谱系的物种形成模式，得到的结果进行解释。此外，牙冠咬合图像，化石模型的三维扫描，以及牙科公制，非公制和标志性的测量，由该项目产生的是未来的研究意义重大。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

This doctoral dissertation project analyzes the variation in size and shape of dental traits among hominins from fossil teeth that are dated to 4.2-3.0 million years ago. The availability of fossil teeth this old has increased significantly in the last decades, yet many of these findings are of isolated teeth that remain unattributed to any species or genus. To address this issue, the doctoral student uses a new approach that allows for improved taxonomic identification of ancient hominin teeth and furthers the understanding of dental and morphological boundaries between these hominin species. Information derived from hominin fossil teeth that are not assigned to a species cannot be fully integrated into paleo-anthropological analyses and remain underutilized. In addition to training a graduate student the project includes the training of undergraduate students, along with plans to share results with the public through outreach activities, and the resulting 3D scans will be made available in public repositories. This project collects metric, non-metric, and two-dimensional landmark data from the teeth of all known Pliocene hominin species dated to 4.2 to 3.0 million years ago. The goal is to assess the affinity of numerous taxonomically unattributed isolated teeth that come from sites dated to that period. The large sample size of teeth in each of the comparative species allows meaningful observations in terms of identifying discrete dental traits or set of traits for each taxon. Once identified, these can be used in the taxonomic identification of newly discovered isolated teeth. Results obtained are interpreted considering recent hypotheses regarding Pliocene hominin diversity and the mode of speciation in the Australopithecus anamensis-Australopithecus afarensis lineage. Furthermore, the occlusal images of tooth crowns, three-dimensional scans of fossil casts, and dental metric, non-metric, and landmark measurements generated by this project are significant for future research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.