Wang Xiaolin's team at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences recently announced that they have found two new early Cretaceous theropod dinosaur footprints in the Urhe region of xinjiang's Junggar Basin.
Among them, the large footprint established a new species, the Niu's Asian footprint, which is the largest Known Asian footprint in the world. The research team combined the size and morphological characteristics of these two footprints to deduce the appearance and morphology of the traceable dinosaurs at that time and the environmental characteristics of their survival.
Wild fossil photographs, models and line drawings of the Niu's Asian Footprint (new species). (Photo courtesy of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences)
Two of the trace dinosaurs were carnivorous dinosaurs
On June 4, Wang Xiaolin, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, told reporters that the two dinosaur footprints were found in Urhe, and they were preserved on a gray-green fine-grained sandstone level of about 12 meters long, about 7 meters wide and with an area of about 80 square meters. He said that through detailed observation of footprints and track characteristics, the research team identified two types of three-toed dinosaur footprints, large and small, 47 cm to 56 cm long and 31 cm to 42 cm wide, in a V-shaped shape, bipedal walking, clear toe pads, and blunt claw tips. The single step of the traceable dinosaur is about 1.64 meters to 1.8 meters long, and the compound step is 3.28 to 3.36 meters long. Some of the characteristics of the medium footprint are consistent with the large footprints, which are about half the length of the large footprints, with a total length of 21 cm to 27 cm and a width of 18 cm to 20 cm.
The research team analyzed the size and morphological characteristics of the footprints, which are similar to the footprints of the Shrystrex family, and are attributed to the Asian footprint genus, "the traced dinosaurs of both footprints are carnivorous theropod dinosaurs," Wang Xiaolin said, because the large footprints are different from the two species of the known Asian footprint genus, so the research team established a new species of the Asian footprint genus, the Niu's Asian footprint. It is reported that this new Asian footprint species is about 1.5 times larger than the known largest Asian footprint, and is the largest type in the Asian footprint genus. The medium footprint is classified as the known Heel Pad Asia Footprint.
Wang Xiaolin analyzed that the study found that the composition and diversity of the Urhe pterosaur fauna enriched, and further confirmed that in the Early Cretaceous Period, the Junggar Basin had a large number of dinosaurs and other vertebrate groups including a variety of theropod dinosaurs, "Here is not only a very important Cretaceous fossil production area in China, but also has a unique scientific research and science education value." ”
Followed by photographs, models and lines of fossils in the field of The Footprint of Asia. (Photo courtesy of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences)
Recreate the living state of the dinosaurs hundreds of millions of years ago
Based on the formula of academic experience, the research team also reproduced the height and length of the two traceable dinosaurs and their living environment.
"We estimated the hip height and body length of the traceable dinosaurs by foot length." Li Yang, a member of the research team and a doctoral student, said that in general, the hip height of theropod dinosaurs is about 4 times the length of the hind foot, and the body length is about 2.63 times the height of the hip. "Based on this calculation, the hip height of the Niu's Asian footprint dinosaur is about 2.3 meters, and the body length is nearly 6 meters, which belongs to the large theropod dinosaurs," Li Yang said, and the hip height of the Asian footprint dinosaur was about 1 meter and the body length was about 2.5 meters.
Based on the values of hip height and compound step length of the traced dinosaurs, the research team further calculated the walking speed of two kinds of dinosaurs, "The walking speed of the Niu's Asian footprint dinosaurs was about 8 kilometers per hour, and the speed of the Asian footprint traceable dinosaurs was about 6.5 kilometers per hour." They were walking at a slower pace. Li Yang said.
They deduced from the symmetrical wave marks, insect traces and complete preservation of footprint fossils preserved at the footprint level that the two types of traced dinosaurs should have strolled in the lakeside environment at that time, "because the preservation of vertebrate footprint fossils, including dinosaur footprints, requires certain special conditions, and only the substrate environment with moderate humidity, viscosity and particle size is the most suitable for footprint preservation," Wang Xiaolin said, if the substrate is wet and soft, after the dinosaurs step on and leave, the surrounding mud will quickly backfill, and the footprint form will disappear, if the substrate is harder, Dinosaurs can't leave marks after walking. "After the dinosaurs left footprints, they were continuously exposed to hardening in the air, and then quickly backfilled with sediment, so that the footprints could be perfectly preserved, so only the coastal environments such as lakes, coasts and rivers that were often exposed to the water were more conducive to the preservation of footprints."
Niu's Asian Footprint and Heel Pad Asian Footprint and Tracer Ecological Restoration Map. (Photo courtesy of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences)
Urho is located on the northwestern edge of the Junggar Basin, about 100 km from the city of Karamay, where a large number of fossils of paleontology are distributed.
As early as the 1960s, researchers began the discovery and study of pterosaur fauna here. And found here Wei's Dzungar pterosaur, turtle turtle, crocodile and a variety of dinosaur fossils, researchers have compared and studied the fossil-rich strata, proving that Urho is a new site rich in Early Cretaceous terrestrial vertebrate fossils, and named this vertebrate fossil group Urhe Pterosaurus fauna.
Since 2006, the scientific expedition team of the Institute of Paleovertebrates of the Chinese Academy of Sciences led by Wang Xiaolin has conducted more than ten years of continuous investigation of Mesozoic paleontology and strata in the Tuha Basin and junggar basin in the north and south of the Tianshan Mountains of Xinjiang, and found a large number of pterosaurs, dinosaurs, birds and other footprint fossils in the Hami Basin. A fossil group of footprints of birds and turtles.