Collaborative Research: The geological and paleoecological contexts of early Miocene hominoid evolution

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This project examines the roles of time and environment in the adaptive evolution of early apes by advancing knowledge about the chronology, paleoecology, and species diversity for a set of geographically restricted fossil localities. The research design includes a series of fossil excavations to uncover new evidence of early apes and their habitats, combined with laboratory analyses designed to aid in synthesizing and interpreting these discoveries.

The scientific importance of this project lies in documenting early ape adaptive diversity within specific, highly-resolved chronological and ecological contexts, with major downstream implications for interpreting the origin and diversification of later apes, including hominins. More broadly, this project expands participation in research through training opportunities targeted to underrepresented groups, enhances scientific infrastructure by digitizing invaluable but currently inaccessible field records, and increases public engagement with science through outreach activities aimed at museums and public schools.

Fossil and molecular evidence indicate that the major lineages of humans and apes diverged during the early Miocene (ca. 23-16 Ma). The diversity of ape species and adaptations during that time greatly exceeds modern variation in this group making it difficult to interpret the evolutionary sequence and ecological contexts in which the suite of features shared by living apes and humans appeared.

This project is organized around the central question: Are differences among early apes tied to differences in paleoenvironments, ages, or both? To clarify these relationships, researchers pursue three specific aims: (1) establishing a rigorous chronology of early ape fossil sites; (2) generating high-resolution paleoecological reconstructions for undersampled ape localities; and (3) documenting the diversity of ape species during the early Miocene.

Fossil excavations are conducted at a series of outcrops to better document ape diversity, geological contexts, and habitat parameters. The project employs radiometric and magnetostratigraphy at correlated stratigraphic sections (Aim 1); sedimentological, isotopic, and paleontological analyses (Aim 2); and comparative, morphometric, and phylogenetic analyses of new fossil ape specimens (Aim 3).

Integration of these study results can enable the researchers to contextualize the timing and ecological parameters associated with the emergence of key characteristics in the ape and human lineage, and to subsequently interpret how these early Miocene primate communities contributed to the distribution of primates across broad regions.

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.