Reptile trace fossils found in Middle Triassic Guanling Formation of northeast Yunnan area

In the Middle Triassic Guanling Formation in northeastern Yunnan, the authors discovered for the first time the footprints of the four-legged and five-toed reptile. These footprints are in a straight line, including large and small footprints, while large and small footprints appear in tandem. The shape of these footprints is very similar to that of human fingerprints. In general, the third toe is the longest and the thumb has an everted curve. It is initially judged as the footprint of "Chirotheriu". This discovery is of great significance for studying the species, migration, movement patterns of the Mesozoic reptiles and the paleogeographic environment.