A crocodilian coprolite from the lower Oligocene Viborg Formation of Sofienlund Lergrav, Denmark

Abstract

A large, well-preserved vertebrate coprolite found in the clay pit Sofienlund Lergrav, Jylland, is identified as crocodilian due to its size and morphology. The coprolite consists of several concentric layers wrapped around a more homogeneous core. Weak constriction marks are present on the surface. Dinoflagellate cyst contents of the coprolite indicate a mid-Lutetian to earliest Rupelian (middle Eocene to earliest Oligocene) age, which at Sofienlund Lergrav places it within the lower Oligocene Viborg Formation. The coprolite can thus be dated as approximately 33–34 Ma old. The Viborg Formation in Denmark represents a period with deposition of hemipelagic marine clay and formation of glaucony. The nearest shoreline was located c. 200 km north of the location of the present day Sofienlund Lergrav, and the climate was humid, warm-temperate to sub-tropical. The presence of a crocodilian coprolite is an important addition to the sparse Oligocene vertebrate fauna of Denmark, which previously only consisted of sharks and cetaceans.