Doctoral Dissertation Research: Identifying dental morphological variation among Pliocene hominins

Arizona State University, Scottsdale AZ

Investigators

Abstract

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.