Researchers led by Wang Xiaolin from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences deduced that the three-toed footprint belongs to a theropod dinosaur. Photo: Courtesy of the research team

The largest species of Asianopodus footprints has been discovered by a research team of the Chinese Academy of Sciences in the Junggar Basin located in Northwest China's Xinjiang Uygur Autonomous Region. Scientists say that the large three-toed footprints are a new species.

The fossilized footprints are 47-56 centimeters long and 31-42 centimeters wide. Judging by its shape, researchers led by Wang Xiaolin from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences deduced that the three-toed footprint belongs to a theropod dinosaur.

The new species is about 1.5 times longer than the largest previously recorded Asianopodus footprint, and it has been considered as a new species called Asianopodus niui. The largest previously recored Asianopodus footprint is 38 cm long and was found in North China's Inner Mongolia Autonomous Region in 2011. 

According to the footprint length, pace and stride length, the trackmaker's hip height of A. niui is about 2.3 meters and the body length is 6 meters.

Meanwhile, the speed of the trackmaker is closely related to the hip height and stride length, researchers calculated that the speed of the trackmaker is about 8 kilometers per hour.

Judging by the symmetric ripple marks and invertebrate traces on the surface of the footprints layer, researchers inferred that the trackmaker of A. niui  walked in the shore and shallow lacustrine environment.

In Japan, the genus of Asianopodus was first discovered and established in 2005 and the type species is A. pulvinicalx. In China, many Asianopodus footprints have also been discovered in Inner Mongolia Autonomous Region.

In addition to the large three-toed footprints, the research team led by Wang Xiaolin also found 5 medium-sized tridactyl footprints (two trackways) on the same tracksite, which belong to A. pulvinicalx. Since 2006, the research team has found a large number of pterosaur, dinosaur, turtle and bird footprints in the Junggar Basin.

The fossilized footprints are 47-56 centimeters long and 31-42 centimeters wide. Photo: Courtesy of the research team