First discovery of dinosaur footprints in the late Middle Jurassic in Ansai district, Shaanxi Province

During the field geological survey in Ansai area, four dinosaur footprints were found in a set of sandstone strata on the top of Zhiluo Formation, three of them were three-toed dinosaur footprints.In addition, three suspected dinosaur footprints were observed.Based on the comparison of footprints characteristics, it is inferred that the three-toed dinosaur footprints of the P3 observation point are largely caused by carnivorous dinosaur, the other footprints are difficult to identify.This discovery not only expanded the distribution of dinosaur footprints in the Ordos Basin during the Middle Jurassic, but also provided materials for further studying the paleoenvironment of the late deposition of Zhiluo Formation.