MIOCENE SHARK-BITTEN VERTEBRATE COPROLITES FROM CALVERT CLIFFS, MARYLAND

Coprolites (fossilized feces) preserve a wide range of biogenic inclusions, from bacteria and spores to a variety of vertebrate tissues. Two coprolites from the Miocene Chesapeake Group of Calvert Cliffs, Maryland, preserve shark tooth impressions in the form of partial dental arcades. These specimens are the first-known coprolites to preserve vertebrate tooth impressions. They provide another example of how trace fossils give evidence of prehistoric animal behaviors not directly available through the study of body fossils. Shark behaviors that could account for these impressions include: 1) aborted coprophagy, 2) benthic or nektonic exploration, or 3) trophic interactions like scavenging/predation. It is possible that the impressions were made in the feces when the teeth punctured the intestinal wall of a prey being bitten by the shark.