Doctoral Dissertation Research: Identifying dental morphological variation among Pliocene hominins

这个博士论文项目分析了人类牙齿化石中牙齿特征在大小和形状上的变化，这些化石牙齿可以追溯到420万年前到300万年前。在过去的几十年里，如此古老的牙齿化石的可用性显著增加，但这些发现中的许多都是孤立的牙齿，仍然不属于任何物种或属。为了解决这个问题，这位博士生使用了一种新的方法，这种方法允许改进对古代原始人牙齿的分类识别，并进一步了解这些原始人物种之间的牙齿和形态边界。没有归类于某一物种的人类化石牙齿所获得的信息不能完全纳入古人类学分析，而且仍未得到充分利用。除了培训研究生外，该项目还包括对本科生的培训，以及通过外联活动与公众分享成果的计划，由此产生的3D扫描将在公共储存库中提供。这个项目收集了公制的、非公制的和二维的地标数据，这些数据来自所有已知的上新世人类物种的牙齿，可以追溯到420万到300万年前。目的是评估许多分类上没有归属的孤立牙齿的亲和力，这些牙齿来自那个时期的遗址。在每个比较物种中，牙齿的大样本大小允许在识别每个分类单元的离散的牙齿特征或特征集方面进行有意义的观察。一旦鉴定出来，它们就可以用于新发现的孤立牙齿的分类鉴定。根据最近关于上新世人类多样性和南方古猿-南方古猿谱系物种形成模式的假说，解释了所获得的结果。此外，牙冠的咬合图像、化石铸型的三维扫描以及由该项目产生的牙齿测量、非测量测量和地标测量对未来的研究具有重要意义。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.