THE SCOOP ON POOP: CONSTRUCTING A PREY SIZE MODEL FROM THE INCLUSIONS OF COPROLITES OF THE SMOKY HILL MEMBER, KANSAS

The Smoky Hill Member of the Niobrara Chalk (Late Coniacian to Early Santonian), Kansas is renowned for its diverse assemblage of vertebrate and macroinvertebrate faunas. The formation also boasts an abundant and varied assemblage of coprolites, though there have been limited comprehensive studies conducted on these fossils. Producers of the fecal products are broadly attributed to teleost fish and marine tetrapods based on their variously spiraled and non-spiraled morphologies, and the inclusions they contain. Segmentation analyses of several of these coprolite specimens have determined that vertebrate bones are among the inclusions found within these coprolites, indicating the types of prey consumed by their producers. Studies of the vertebrate inclusions within modern marine predator fecal products have indicated that measurements of particular prey remains, such as fish vertebrae and otoliths, can serve as a correlate for prey body size, providing insight into the average prey size range for a particular predator. This study employs non-destructive X-ray microscopy to explore the taphonomic attributes of the internal structures and inclusions of a subset of the Smoky Hill Member coprolites and utilized linear regressions of basic dimensions of prey inclusions, such as vertebral length and width, to develop an overall size model for the range of prey body sizes consumed by a particular coprolite’s producer. This work provides a clearer picture of the feeding behaviors and prey size preferences of the producers of these coprolite samples whilst simultaneously capturing unique paleoecological and paleoenvironmental information within the Smokey Hill Member.