Theropod swim traces in the Santisol tracksite (Lower Cretaceous), Cameros Basin, La Rioja, Spain

Abstract

Swim traces are rare in dinosaur track sites worldwide. This article reports three sets of theropod swim traces found with walking tracks in the Santisol tracksite (Cameros Basin, La Rioja, Spain). The tracksite contains over one hundred theropod and a few ornithopod walking tracks previously reported. The swim traces are well-preserved and do not show evidence of sediment collapse that characterizes the true tracks. One of the swim traces cuts through one theropod track, indicating that the walking prints formed first, followed by the rise of the water level and the formation of swim traces by swimming theropods.