The drought in American rivers reveals the footprints of dinosaurs 1 100 million years ago. When did dinosaurs first appear?

Affected by dry and hot weather, a river in Dinosaur Valley State Park in Texas dried up, and a large number of dinosaur footprint fossils were rediscovered, the oldest of which can be traced back to1.1.300 million years ago. Most of the footprint fossils belong to adult spinosaurus, about 15 feet high and weighing about 7 tons. Under normal weather conditions, these dinosaur footprint fossils are located underwater and covered by sediments, so it is difficult to find them. It is expected that these footprints will be buried again after the rain, which will also help protect them from natural weathering and erosion. The footprints left by dinosaurs walking on the surface of fossils formed after loose sediments, diagenesis and preservation. They are formed in situ, which can best reflect the original sedimentary environment and have a good indication for the ancient environment of lake shore and nearshore. As the research object of paleontology, dinosaur footprint fossils are also important data for studying dinosaur physiology and living habits.

Is the dinosaur footprint fossil an animal activity recorded by nature with a natural video recorder? Close-up? , is the footprint of natural history. Dinosaurs first appeared in the late Triassic about 235 million years ago. Dinosaurs first appeared in the late Triassic about 235 million years ago and died in the late Cretaceous about 65 million years ago. Extinction event. During the Triassic period, vertebrates developed further. Alveodon reptiles appeared, from which the earliest dinosaurs developed. There are many kinds of sauropods and ornithopods. Dinosaurs are already a diverse group, occupying a large part of the ecosystem. Triassic is also called? Dawn before the age of dinosaurs? .

The earliest reptile phobia mammals evolved from theropod reptiles, but these animals did not live in the same period as mammals in the long years from Jurassic to Cretaceous. The shadow of reptiles has been dominated by dinosaurs until the Cenozoic era. It took scientists 10 years to finally get the preliminary results. They found this crater in the strata of Yucatan Peninsula in Central America and Mexico. It is estimated that the diameter of this pit is between 180-300 km. In 2000, scientists were still doing further research on this pit.