USING DIGITIZED SPECIMENS TO UNDERSTAND THE DIVERSITY OF FOSSIL COLEOPTERA (BEETLES) FROM THE GREEN RIVER FORMATION, USA

The University of Colorado Museum of Natural History (UCM) houses ~100,000 fossil insects from the Green River Formation, western Colorado. These specimens collectively represent ancient communities once living in the North American continental interior just after global temperatures began cooling ~50 Ma, making them well-suited for investigating ecological patterns in the context of climate change. While digitization of this collection has been ongoing for almost a decade, a more recent comprehensive approach, including digital imaging, is currently supported by the Fossil Insect Collaborative TCN project. The imaging aspect of the TCN project is crucial, as it has enabled comparisons of Coleoptera (beetle) from two end-member assemblages using the digital images.

To date, over 7,700 Green River fossil insect specimens have been imaged, and a subset of beetles were chosen as focal taxa: carabids, staphylinids, and curculionids. Within these groups, 580 imaged beetles from two localities were separated into various distinct morphospecies and counted. By applying rarefaction methods to these abundance data, we found overall beetle community richness did not significantly change with time. This pattern held when beetles were compared by feeding guild (herbivores versus non-herbivores) and taxon. Body size measurements were also documented. There is some evidence that compositional turnover may have occurred in the beetle community with time, and investigation into this research question remains in progress.

Having access to digital specimen vouchers enabled components of this project to be completed relatively quickly, in part because specimens could be easily shared with specialists for assistance with morphospecies verification and identification. Further, by approaching this project using digital images, the fossil insect digitization team gained insight into the advantages, challenges, and unknowns of using digital collections for research. Consequently, this undertaking catalyzed refinement of the UCM’s digitization workflow and procedures to produce images that better accommodate research needs. Accessibility to specimen data and images through iDigPaleo will facilitate future research collaboration.