Two years ago, by chance, zhejiang museum of natural history Jin team found the footprints left by a dinosaur during a field trip in Yiwu: four right foot footprints, five left foot footprints and a series of ***9 footprints.

The Cretaceous is a "turbulent" era. The continents on the earth are separated by oceans, volcanic activities are frequent, the earth becomes warm and dry, and great changes have taken place in the biological world ... During this period, dinosaurs came and went freely, but only footprints left on moderately soft and hard soil layers can form fossils, not to mention that time has passed 654.38 billion years.

Recently, the gold team of Fukui Dinosaur Museum in Japan and their colleagues published the research results of this dinosaur footprint fossil online in the international professional geoscience journal Cretaceous Research, and tried to judge the movement state of this dinosaur at that time.

who is it? What is it doing?

They judged that dinosaurs might have been "walking" at that time.

In 20 19, the team found this fossil in Yiwu, and its footprint was consistent with that of Sichuan Raptors. Deinonychus' paw on the second toe of its hind foot was particularly large, and it was held high and generally did not touch the ground. Therefore, when deinonychus walked, only the third and fourth toes landed on its hind feet, and the footprint was a very typical two-toed structure. So the dinosaur footprints found this time were left by deinonychus dinosaurs.

The team of researchers measured the length and width of dinosaur footprints, the angle between two toes, the length and complexity of single step according to fossils. On this basis, it is estimated that the dinosaur in the next footprint is about 50 to 67 cm high, and then the speed is calculated according to the step width.

But deinonychus can be divided into red dragon and toothless dragon. Due to the different proportions of hind legs of the two types of dinosaurs, the calculated heights are also different.

Therefore, the researchers analyzed according to two situations: if it is a red dragon, the calculated height is 5 1.8cm, and the walking speed is 6.1km/h; If it is odontosaurus, the calculated height is 65.6 cm and the walking speed is 4.6 kilometers per hour.

But no matter what kind of dinosaur, judging from the inferred speed, it was in a leisurely state at that time-its speed was almost the same as that of human beings (the speed of human walking was generally 4~7 km/h). Because if it is predation or escape, it is said that odontosaurus can run at a speed of 60 kilometers per hour, just like a running horse.

How did you find out?

In recent years, Zhejiang Provincial Museum of Nature, together with provincial museums and Japanese Fukui Dinosaur Museum, conducted a lot of field visits in Zhejiang, and found and protected a number of paleontological fossils.

It is reported that the footprints of sauropods, birds, non-deinonychus theropods and pterodactyls have been found in Zhejiang before. This is the first time that the footprints of deinonychus dinosaurs have been found in Zhejiang.

Jin recalled that pterosaur footprint fossils were first discovered at that time. "Pterosaur footprint fossils were found in the rubble left by road construction. We want to find its original position on the mountain and see where it was excavated. The result was unexpected. Deinonychus footprint fossils were found in the upper layer of pterosaur footprint. "

Follow the trail, follow the direction of the footprints, and finally find nine footprints that walk continuously on a stone.

Looking back at the discovery process at that time, Jin described it as "very pleasant surprise" because only deinonychus eggs were found in Zhejiang before, and no footprints were found. This is the first time that deinonychus footprints were found in Cretaceous strata in southeastern China, which further confirmed that deinonychus dinosaurs once lived in Zhejiang.

It is understood that in Asia, only the bones of Deinonychus were found in the north, while only the footprints of Deinonychus were found in Sichuan in the south.

Why did it come here?

This set of footprints was found in Guanyintang Village, Jiangdong Street, Yiwu.

It is reported that the dinosaur footprint fossils in Guanyintang Village are all from the late Cretaceous strata, dating from 80 million to 654.38 billion years ago. In Guanyintang village and its surrounding area, paleontologists also found dinosaur bone fossils and dinosaur eggs preserved in the whole nest. The largest sauropod footprint fossil and the first theropod footprint fossil in Zhejiang were unearthed, which turned out to be multiple footprints left by a theropod dinosaur.

This place is called "dinosaur paradise", and the richness of fossil groups is shocking:

20 10 researchers from the Institute of Geology, Chinese Academy of Geological Sciences, while studying Dongyang dragons unearthed in Dongyang Museum, saw many local dinosaur eggs unearthed in the museum and decided to investigate the strata near the dinosaur eggs. Results Three-toe dinosaur footprint fossils were found in a construction site near Houyantou Mountain.

Since 20 14, researchers in zhejiang museum of natural history have conducted a detailed investigation here-more than 20 strata containing dinosaur footprints and more than 80 dinosaur footprints have been found.

"There are new discoveries every year, and they are all different kinds. For example, the footprint fossils of theropod dinosaurs were discovered in the first year, pterosaurs were discovered in the second year, sauropod dinosaurs were discovered in the third year, and ornopod dinosaurs were discovered in the fourth year. " Jin said that although the current discovery can only be regarded as the tip of the iceberg, it is already the largest dinosaur footprint fossil in the southeast coastal area of China, which is rare in the world.

Why are you here? Jin Shengxing explained that the stratum where dinosaur footprint fossils were found belongs to Jinhua Formation, which is widely distributed in Jinqu Basin in central Zhejiang. The Jinqu Basin in Yiwu was full of streams at that time. At that time, the climate here was periodically hot and humid, and the vegetation was rich, which was suitable for dinosaur life.