Late Cretaceous coprolite from the Opole area (southern Poland) as evidence for a variable diet in shell-crushing shark Ptychodus (Elasmobranchii: Ptychodontidae).

Abstract

Coprolites, i.e., fossilized faeces, are an important source of knowledge on the diet and food processing mechanisms in the fossil record. Direct and indirect evidences for the dietary preferences of extinct sharks are rare in the fossil record. The first coprolite attributable to Ptychodus containing prey remains from the European Cretaceous is documented here. A coprolite from the Late Cretaceous of Opole (southern Poland) was scanned using micro-computed tomography to show the arrangement of the inclusions. In addition, the cross-section was examined under the SEM/EDS to analyse the microstructure and chemical composition of the inclusions. Brachiopod shell fragments and foraminiferan shells are recognized and identified among the variously shaped inclusions detected through the performed analysis. The extinct shell-crushing shark Ptychodus has been identified as the likely producer of the examined coprolite. The presence of brachiopod shell fragments indicates that at least some species of this durophagous predatory shark may have preyed on small benthic elements on the sea bottom.