A diverse theropod footprint assemblage from the Lower Cretaceous Kitadani Formation, Tetori Group, central Japan

Abstract

Theropod footprints occupy more than 50% of dinosaur footprints from the Lower Cretaceous Kitadani Formation of the Kitadani Dinosaur Quarry in Fukui, central Japan. However, ichnotaxonomical description of these footprints has never been carried out. In this study, five different ichnotypes, which are the ichnofamilies Grallatoridae, Eubrontidae, and Ornithomimipodidae, and the ichnogenera Asianopodus, and Minisauripus, are described. Among them, morphological variation between the ichnofamilies Grallatoridae and Eubrontidae, and the ichnogenus Asianopodus show the same pattern with the Grallator–Anchisauripus–Eubrontes plexus, which is suggested as an ontogenetic or phylogenetic phenomenon. Occurrence of the ichnogenus Minisauripus indicates that the theropod ichnofauna of this quarry has a strong correlation with those of South Korea, Shandong Province, and Sichuan Province. In addition, discovery of the ichnofamily Ornithomimipodidae from this quarry is the second report of this ichnofamily from Asia and extends its distribution. This report adds important information for better interpreting the paleobiology, paleoecology, and paleogeography of the Kitadani Dinosaur Quarry, and it is also important for those of Asia Continent during the Early Cretaceous time.