Dinosaur footprints from the Lower Jurassic (Hettangian–Sinemurian) Precipice Sandstone of the Callide Basin, Queensland, Australia

Abstract

Dinosaur footprints have been reported from the Lower Jurassic (Hettangian–Sinemurian) Precipice Sandstone of the Callide Basin, Queensland, for over three decades, yet only a single track has been described until now. This study reports additional tracks on three ex-situ surfaces not previously described. These pedal impressions are assignable to the ichnospecies Anomoepus scambus, attributed to ornithischian dinosaurs. One surface contains a single print, a second a trackway with two tracks, and the third features at least 13 trackways and numerous isolated prints representing one of the most densely concentrated dinosaur track surfaces in Australia. Dinosaur trackmakers were estimated, with hip heights ranging20–76 cm and exhibiting walking gaits with speeds of 2.15–5.78 km/hr. Small, infilled circular traces, possibly invertebrate burrows of the ichnogenus Skolithos are abundant on the surfaces that, if correct, indicate the tracks were formed in subaqueous, moderate-to-high energy conditions. With no dinosaurian osteological record from Australia’s Early Jurassic, these footprints provide valuable evidence for the presence, abundance, and behaviour of ornithischian dinosaurs in the region.