Who are the natural enemies of dinosaurs?

Not long ago, some strange footprints were found on the Jinsha River. The footprint was about 2 1 10,000 years ago, that is, the late Triassic. According to the research of paleontologists, it is preliminarily inferred that the owner of the footprint is a "hand beast" belonging to the main dragon crocodile. This monster is over 5 meters in size. It is undoubtedly the top predator in Sichuan and other continents in the Late Triassic. Early dinosaurs were no match for them at all, so they were easily "killed" and eaten as snacks. Paleontologists in China, the United States and Germany disclosed the discovery process of hand-beast footprint fossils.

Hand and beast footprints found along the Jinsha River, these main crocodiles can easily "kill" early dinosaurs.

-Found-

Footprints of monsters in Panzhihua, Sichuan

Li Xuezhi, chairman of Panzhihua Photography Association, was the first person to find fossil footprints of monsters. He is also a collector of strange stones. Last year, Li Xuezhi heard that there was a very special animal footprint on the hillside of a local town a few kilometers away from Jinsha River, which might be dinosaur's. "In my impression, Panzhihua has never found any remains related to dinosaurs." Li Xuezhi said, but out of curiosity, he went to the scene. "These footprints are very different from the dinosaur footprints I have seen in books: these footprints are not three or five toes, but four toes with strange shapes."

Due to lack of evidence, he didn't disclose information to the outside world until last August, when he learned that a paleontologist had come to Sichuan, and he told the news to two experts and reporters.

Under the leadership of Li Xuezhi and friends, the reporter arrived at the place where the "dinosaur footprint" was discovered. This is a taupe rock hidden under a forest, and some of it has collapsed, revealing less than 10 square meter. On the rocks, there are 10 odd "paw prints" left by seemingly animals. After taking photos and drawing, the reporter passed the information to Xing Lida, a dinosaur footprint expert from China Geo University.

Formed 265438+10 million years ago.

"This is definitely not an ordinary discovery!" After seeing the photo, Xing Lida determined that it was a fossil animal footprint. In March this year, Xing Lida and reporters rushed to Panzhihua. In order to better evaluate the geological age, this trip also invited Kan Zezhong, vice president of Sichuan Geological Survey Institute.

On the bank of Jinsha River, Xing Lida and everyone began to clean up the scene again, carefully measured the footprints, and copied all the footprints with plastic film after taking photos. After several hours of cleaning, on this sloping rock of 10 square meters, all the footprints of 10 rules are presented to everyone. Due to the long-term exposure to the sun and rain, the footprints have weathered off, but the shape can still be seen clearly. According to the measurement, these footprints are about 45 cm long and embedded in the rock to a depth of more than 1 cm. "I've seen almost all the dinosaur information or footprints in China, and the footprints in front of him have never been seen by himself. It can be preliminarily judged that these footprints are not left by dinosaurs, but from another kind of' monster'. " Xing Lida said.

After on-the-spot investigation, Vice President Kan Zezhong also quickly reached a conclusion about the age of the rock stratum where the footprints were located. Combined with the scattered plant fragments fossils found near the fossil site, he thinks it belongs to the late Triassic Baoding Formation, 2 10/00000 years ago.

-The problem is-

Whose footprints are they?

After bringing the field investigation data back to Beijing, Xing Lida also sent the data to his international colleagues-Hendrick Klein, a professor at the German Museum of Ancient Reptiles and Amphibians, and Martin Lockley, a professor at the University of Colorado (Denver) who visited the dinosaur tracks in China many times. Scholars from China, Germany and the United States, after detailed research, agreed that the footprints of Panzhihua monsters were mainly left by dragons.

The main dragon, also known as Chulong and Zulong, means "dominant lizard" in Greek. It is a major evolutionary branch of reptiles, including dinosaurs and pterosaurs, leaving only crocodiles and birds. Because of its important position in evolution, the fossils and footprints of the main dragon have very important scientific value.

Xing Lida said that the footprint fossils of Panzhihua are very similar to the back footprints of hand-beast footprints in terms of overall shape. At present, the footprints of hand animals are thought to be left by crocodiles in the main dragon. "For example, the second to fourth toes of the footprint are very compact and symmetrically distributed, with the third toe being the longest and the slender fifth toe pointing to the back."

How did you leave footprints?

Xing Lida said that according to the data obtained from the survey, we can go back to 200 million years ago and imagine the appearance of footprints: the hard dry season is coming, and the midday sun is fierce. In this place like an alien world, there are a group of small carnivorous dinosaurs with strong adaptability to the environment. They are about 1 m long and are both active predators and scavengers. After a hearty meal, they went into the bushes. 10 meters away, a 5-meter-long fake crocodile (the main dragon in the text) is eyeing the carnivorous dragons. It is the largest carnivore in this era, and a typical fast predator before the rise of dinosaurs. It has a strong skull, sharp teeth and quick action.

The crocodile galloped in the thorny grass, and it chose a young dragon parked on the side of the road to eat. The little guy was eaten alive before he could scream. A few minutes later, the crocodile left the prey site and went to the lake to rest, leaving a long trail on the moderately soft and hard shoal. The hot sun soon dried the footprints, and then they were covered. After a long time, it became a fossil after 200 million years.

Can you "kill" early dinosaurs?

Xing Lida told reporters that the footprints of hand animals were also recorded in the strata of Guanling Formation in Middle Triassic in Guizhou, but the footprints of Guizhou and Panzhihua are different and should belong to different species. "However, Panzhihua has a small footprint and should be a new species. However, due to the need for more evidence, it has not been classified as a species with undetermined footprints."

Xing Lida said that the longest hand-beast footprint in Panzhihua is about 45cm, which means that the crocodile that left these footprints is more than 5m long. In Sichuan in the late Triassic, even in other continents, it was undoubtedly a top predator, and the early dinosaurs were no match for it at all, so it could easily "kill" it.

Vice President Kan Zezhong believes that the discovery of hand-beast footprints in Panzhihua is very important, and these animal records, together with the flora at that time, constitute a more complete ancient ecosystem. In the strata where footprints are found, the ancient environment is rivers and lakes, and some areas are occasionally connected with the sea. This is of great significance to study the paleogeography and paleoclimate of Panzhihua, and even to the mineralization and prospecting of Panxi Rift Valley.

-Unresolved-

Is this hand beast roaming or hunting?

Xing Lida said that if there is an opportunity, there may be more footprints after cleaning the soil near the footprint. Local villagers said that the place where the footprints were found had been collapsing. They had seen sporadic footprints on the stone before, but they didn't know what they were and nobody cared. Now, these stones have been smashed to pave the way. Although these footprints have been identified as hand-beast footprints, in the eyes of scholars, the mystery behind the footprints has not been completely solved. Xing Lida said that there are still many questions: Was it roaming or hunting? If it is hunting, why does its stride look so short? In addition, their footprints are very different from those of the newly discovered five-toed hand beast in Europe ... Faced with these unsolved mysteries, Xing Lida said that this is the charm of footprints.

■ Extended reading

Monster footprints first appeared in 180 years ago.

1833, a number of strange footprints were found in Hausen County, Hildeburg, south of Thuringia, Germany. They look like "thick animal leather gloves worn by a big man", which is called manual animal footprint, which means "manual animal" in Greek.

This "big glove" has a horizontally separated "thumb", which is strangely located on the "outer side" of the footprint, which does not conform to the existing growth tradition of terrestrial animals. This kind of confusion has caused controversy in academic circles for more than 1.7 years. At first, geologists first thought that these "handprints" belonged to early apes or ancient humans. 1842, the famous anatomist Owen believed that these footprints were left by amphibians. Up to 19 14 and 19 17, scholars believe that the footprints of manual animals were left by some primitive dinosaurs.

1925, German scientist Siegel linked hand-shaped animal footprints with crocodile fossils in South Africa. Pseudouropoda, originally used to refer to Triassic reptiles, belongs to the main dragon. It is a kind of carnivore with a relatively light body structure, generally between 35 cm and 8 m in length, and became the dominant group of carnivores on land in the late Middle Triassic. Crocodiles today are the surviving species in this ancient family.

Even so, the view that "the footprint of the hand beast was made by a pseudo crocodile" has not been fully recognized at present, and some scholars still insist that it was made by a theropod or a primitive sauropod, and the mysterious veil on the animal has not been completely uncovered.

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