Dinosaur, bird and pterosaur footprints from the Lower Cretaceous of Wuerhe asphaltite area, Xinjiang, China, with notes on overlapping track relationships

An assemblage with well-preserved dinosaur, bird and pterosaur footprints has been found in deposits of the upper Tugulu Group (Lower Cretaceous) of the Wuerhe asphaltite area (Junggar Basin, Xinjiang, northwestern China). The dinosaur footprints are similar to the theropod ichnogenus Jialingpus, and the bird footprints to shorebird-like footprints. The isolated tridactyl imprint of a pterosaur manus resembles the ichnogenus Pteraichnus. All morphotypes are also known from another locality in the Junggar Basin, the Huangyangquan tracksite. The different size-classes of theropod footprints are inferred to indicate adult and juvenile individuals. The paleoenvironment was clearly favorable for the co-existence of mixed-age theropod communities, shorebird-like birds, and pterosaurs. An interesting feature is the unusual preservational mode and overlap of footprints that show plastic deformation without fracturing.