129-76 Shining a new light on modern raptor pellets as taphonomic analogues

Abstract:

Fossil evidence indicates ancient animals have utilized regurgitation as a means of removing indigestible materials since the Early Permian (~290 Ma). Bromalites, which include coprolites (fossilized feces), cololites (gut contents), and regurgitalites (fossilized regurgitate materials), are the fossilized digestive contents of ancient organisms. Bromalites can provide insight into extinct or ancient predator-prey relationships, feeding habits, and predator digestive systems. This study pairs high powered imaging with the examination of modern raptor regurgitation pellets (RPs) to characterize regurgitate production, contents, and potential for preservation as a framework for interpreting fossil regurgitalites, and further reconstruct feeding ecology and trophic interactions of extinct communities. 

RPs were collected from the University of Missouri’s Raptor Rehabilitation Project from Tyto furcata (American barn owl), Strix varia (barred owl), Haliaeetus leucocephalus (bald eagle), and Buteo lineatus (red shouldered hawk). These species were selected for their variety of digestive characteristics which includes stomach acidity. Regurgitate samples were imaged using X-ray microcomputed tomography (µCT) at the University of Missouri-Columbia X-ray Microanalysis Laboratory, allowing nondestructive, three-dimensional visualization of their internal structures and inclusions. Datasets were reconstructed using Dragonfly Comet 3D software and segmented using an AI-trained algorithm to identify and quantify tissue, fur, and bone elements and characterize their taphonomic grades. Preliminary results show that RP content preservation and element fragmentation, orientation and distribution vary between taxa, and in some cases within the same taxa. Contrary to traditional methods of physical (wet/dry) disaggregation, this non-destructive method preserves the ultrastructure of the pellet which may be useful in comparisons with fossilized analogues.

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