Gastroliths Associated with Plesiosaur Remains in the Sharon Springs Member of the Pierre Shale (Late Cretaceous), Western Kansas

Abstract

Field work conducted in 1991 and 1998 recovered 47 gastroliths in association with the incomplete and disarticulated remains of a large plesiosaur (KUVP 129744). The specimen was discovered in the upper Sharon Springs Member of the Pierre Shale (Late Cretaceous), Logan County, Kansas. The gastroliths are unusually large in size when compared to those documented from other plesiosaur remains, and larger than those associated with the giant sauropod, Seismosaurus. The shapes of the gastroliths are consistent with similar sized stones that occur in river gravel. This specimen provides new data in regard to the range of sizes and the occurrence of gastroliths in these extinct marine reptiles.