Crocodilian coprolite from the lower Oligocene Viborg Formation, Denmark · 181 A crocodilian coprolite from the lower Oligocene Viborg Formation of Sofenlund Lergrav, Denmark JESPER MILÀN, ERIK SKOVBJERG RASMUSSEN & KAREN DYBKJÆR Milàn, J., Rasmussen, E.S. & Dybkjær, K. 2018. A crocodilian coprolite from the lower Oligocene Viborg Formation of Sofenlund Lergrav, Denmark. © 2018 by Bulletin of the Geological Society of Denmark, vol. 66, pp. 181–187. ISSN 2245-7070. (www.2dgf.dk/publikationer/bulletin). A large, well-preserved vertebrate coprolite found in the clay pit Sofenlund Lergrav, Jylland, is identi- fed 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. Di- nofagellate cyst contents of the coprolite indicate a mid-Lutetian to earliest Rupelian (middle Eocene to earliest Oligocene) age, which at Sofenlund 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 Sofenlund 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. Keywords: Coprolite, Palaeogene, Oligocene, vertebrate fauna, Denmark, Crocodilian. Jesper Milàn [jesperm@oesm.dk], Geomuseum Faxe, Østsjællands Museum, Østervej 2, DK-4640 Faxe, Den- mark; also Natural History Museum of Denmark, Øster Voldgade 5-7, DK-1465 Copenhagen K, Denmark. Erik Skovbjerg Rasmussen [esr@geus.dk] and Karen Dybkjær [kd@geus.dk], Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Corresponding author: Jesper Milàn. Coprolites are important palaeoecological indicators and are with increasing frequency included in pal- aeoecological analyses, as they can provide important additional information about extinct animals and their diet, in form of preserved inclusions of undigested prey remains (e.g. Thulborn 1991; Hunt et al. 1994; Northwood 2005; Prasad et al. 2005; Chin 2007; Souto 2008; Eriksson et al. 2011; Milàn et al. 2012a,b; Hansen et al. 2016). Coprolites are regarded as ichnofossils and were first recognised as fossil feces by William Buck- land (1835) who coined the term coprolite. Today ver- tebrate coprolites are known from the Silurian to the present (Hunt et al. 2012). The Danish fossil record of coprolites is sparse, with only a few specimens known from the Lower Cretaceous of Bornholm (Milàn et al. 2012b), the Upper Cretaceous of Stevns Klint (Milàn et al. 2015), the Lower Paleocene (lower Danian) of Hammelev Kalkbrud (Milàn & Hunt 2016), the mid- dle Danian of Faxe Kalkbrud (Milàn 2010) and Bed L2 of the Eocene Lillebælt Clay Formation (Heilmann- Clausen et al. 1985). A new specimen originating from the lower Oligocene Viborg Formation of Sofienlund Lergrav (Fig. 1) is thus the hitherto youngest coprolite from Denmark. The aim of this study is to describe the new-found specimen, identify its producer, and discuss its palaeoecological context. Geological Setting During the Palaeogene and Neogene, the North Sea Basin formed an epicontinental basin (Ziegler 1990). The carbonate deposition that dominated during the Late Cretaceous continued into the earliest part of the Palaeogene (early Paleocene). It was succeeded by deposition of deep marine clays during most of the Paleocene and Eocene (Nielsen et al. 2015 and references therein). Volcanic activity in the North Atlantic became extensive at the Paleocene–Eocene transition and resulted in sedimentation of ash-rich layers throughout the North Sea Basin and diatomites locally in parts of the eastern North Sea area (Peder- sen & Surlyk 1983). During the Oligocene, the first Received 29 August 2017 Accepted in revised form 26 May 2018 Published online 11 September 2018