DINOSAUR FOOTPRINTS AS ULTIMATE EVIDENCE FOR A TERRESTRIAL ENVIRONMENT IN THE LATE SINEMURIAN TRENTO CARBONATE PLATFORM

Abstract

Three dinosaur footprints were found, preserved as natural casts, on the roof of a First World War tunnel in the Pasubio Massif (Trentino Alto-Adige, northeastern Italy). The Austro-Hungarian Army used the tunnel until 1918, presumably to connect the front- with the back line. The tracks are tridactyl, two of which are organized in a trackway, and provide evidence for the presence of medium-sized theropods. The track-bearing horizon is situated at the base of the Rotzo formation (Calcari Grigi Group), within shallow-water black shale deposits characterized by oligotypic small bivalves, oligohaline ostracodes, and thecamebians. Vertebrate remains, represented by crocodyloform teeth and fish scales, were also identified from the same stratigraphic portion. The occurrence of dinosaur footprints from black shale levels sheds light on their controversial interpretation, confirming the occurrence of terrestrial environment in the Trento carbonate platform during the late Sinemurian. Dinosaur tracks indicate the emersion of a sector of the tidal flat during the deposition of the basal Rotzo formation, and suggest a complex paleonvironmental scenario in which tidal flats were associated with freshwater ponds and islands.