LATE CRETACEOUS MARINE COPROLITE RECORD IN THE SOUTHEAST: GETTING IT TOGETHER

Coprolites are common in many sedimentary deposits in the southeastern Coastal Plains; however, they are rarely described, analyzed, or attributed to specific producers. In widespread Late Cretaceous perimarine detrital facies, coprolites are typically phosphatic and retain their original shapes without significant compression or diagenesis. In chalk and marl facies, common in central and western Alabama, marine coprolites are often replaced by pyrite or marcasite, and may experience significant changes in morphology after deposition.

Coprolites in aquatic depositional environments may be distinguished from terrestrial deposition by the absence of a flattened bottom side. Among identifiable fecal marine morphologies, spiral or scroll-shaped coprolites attributable to sharks are the most stereotypical: however, spiral morphology may be easily lost in ablated or mineralogically altered specimens. Also easily identifiable are coprolites of smaller crocodylians, with typically J-shaped posterior terminations, presumably deposited in shallow bays and estuaries. Larger, amphipolar coprolites replaced by calcite have been attributed to the giant, estuarine crocodylian Deinosuchus. Additional marine coprolite morphologies include a previously undescribed form with distinct sphincter marks at both ends, possibly from a larger teleost genus such as Xiphactinus. Some marine coprolites have inclusions ranging from fragmentary fish scales and teeth to complete vertebrae. A very notable small selachian coprolite from South Carolina includes the nearly entire cervical vertebral series from a newly-hatched freshwater turtle, providing insights into predator and prey habitats and behavior.