Chinese scientists find world's smallest known sauropod dinosaur footprints

Scientists recently discovered the world's smallest known sauropod dinosaur footprints in eastern Xizang autonomous region, which are estimated to have lived in the Jurassic Period about 170 million years ago, the research team announced on Friday.

Associate Professor Xing Lida from the China University of Geosciences (Beijing) said that these footprints found in a village in Chamdo city, Xizang, range in size from 8.8 to 15.5 centimeters and are believed to have been left by at least six dinosaurs, identified as Parabrontopodus tracks.

"These tiny sauropod footprints are quite rare. South Korea has recorded 12.2 cm, and the Inner Mongolia autonomous region in China has seen footprints of 11.5 to 13 cm, both in the Cretaceous strata, which is tens of millions of years after the Jurassic Period," Xing said.

Xing and Chen Xinyu, a senior engineer from the physical geological information center for natural resources of the China Geological Survey, published their team's new discovery in the international paleontology journal Historical Biology in late December.

The estimated body length of the owner of the footprints is 2 to 3 meters. These new findings suggest the possible existence of small sauropod dinosaurs in this area of Xizang, providing evidence for their features such as age segregation in sauropod dinosaurs.

Xing explained that there is a significant size difference between adult and juvenile sauropods. Giant sauropod dinosaurs, which can reach lengths of 20 to 30 meters, have hatchlings that are less than half a meter long. This huge difference in size results in different behavior patterns and food sources between them, leading to many sauropod dinosaur groups forming species that act independently based on age.

Alongside these small footprints, three consecutive large footprints of about 42 centimeters belonging to theropod dinosaurs were also found, which can be classified as the ichnogenus of Eubrontes.

"Eubrontes footprints are quite common in the dinosaur footprint records of the Mesozoic Era in China, but they are not as abundant in the Jurassic dinosaur footprint records in Xizang. Their presence represents the existence of medium-sized carnivorous dinosaurs in the region, with a body length potentially reaching six meters," Xing said.

The Qinghai-Xizang Plateau is the highest, largest, youngest, and still rising plateau on Earth. It reflects the complex evolutionary history of the Tethys Ocean, which existed hundreds of million years ago. In areas such as Chamdo, during the Early Jurassic Period, marine sedimentation gradually decreased, eventually transitioning to inland basins by the Middle Jurassic Period.

"This new fossil evidence further strengthens the previous hypothesis that the eastern part of southwestern China was once part of the ancient Tethys Ocean," Xing said.

"This series of new discoveries indicates that there is still ample space for dinosaur research in Xizang. As research progresses, dinosaurs in the region can fully demonstrate their value in both scientific research and public education."