World-class dinosaur fossils continue to show unsolved mysteries
Pu'an Township, Yunyang County, Chongqing City, where "the world's largest Jurassic in-situ single fossil wall" was discovered, not long ago discovered a new large herbivorous dinosaur, Puxian Emeilong. But the new discovery does not stop here. A new "dinosaur mystery" has recently surfaced in Pu'an Township. Researchers discovered during the excavation process that there are also dinosaur fossils in layers older than the layer where the fossil wall is located. What is more exciting is that the newly discovered dinosaur fossils may fill the gap in the evolutionary sequence of dinosaurs from the late Early Jurassic to the Middle Jurassic.
The dinosaur fossils in Pu'an, Yunnan, including the Xintiangou and Shaximiao formations, belong to the period from early Early Jurassic to late Middle Jurassic, which was rarely found in the world before. Dinosaur fossil. The Emei dragon found in the Shaximiao Formation of the dinosaur fauna in Yunyang, after the discovery of two new species of the Modaoxi Three Gorges Dragon and the Pu'an Yunyang Dragon in the Xintiangou Formation of the Pu'an dinosaur fossil group in Yunyang, Chongqing, A new species of dinosaur was discovered again in Yunyang. The Pixian Emei dragon found in this study is a dinosaur individual with a preservation degree of about 40%. "Puxian" is a species name and belongs to the genus Emei. The fossil specimens found include vertebrae, forelimbs, and hindlimbs preserved in some joints, as well as clavicles, ribs, and other materials preserved separately.
The researchers found that the unearthed fossils of the Emei dragon from Puxian are significantly different from the currently known Emei dragons, and have their own unique features. The scoliosis is separated by a secondary partition, the anterior caudal vertebral nerve spinal end expands backward, the humeral deltoid crest points to the posterolateral side, and the ratio of ulna to humerus is 0.69. After the restoration and installation, Puxian Emei Dragon is an adult large herbivorous dinosaur with a body length of about 16 meters, and its head can reach more than 8 meters above the ground when standing.
Tan Chao, a researcher at the Chongqing 208 Geological Heritage Protection Institute, said that the Emeilong genus is one of the main representative dinosaurs in the Middle Jurassic. At the same time, it enriches a group of Emeilong, which is of great significance for studying the evolution and migration of individuals of Emeilong.
The dinosaur fossil group in Pu'an, Yunyang, Chongqing was born out of bone-shaped stones discovered by a local young farmer in Laojun Village, Pu'an Township in January 2015. Experts who heard the news, after identification and on-site investigation, believed that there might be a huge Jurassic dinosaur fossil group hidden in the area. After two years of excavation and protection, a 150-meter-long monolithic dinosaur fossil wall was discovered in Pu'an Township. This fossil wall includes 17 fossil enriched communities, and there are a large number of dinosaur fossils buried deeper than 20 meters under the fossil wall. What is even more surprising is that the outcrops of Yunyang dinosaur fossils spanned 4 townships, and the distribution range was about 15 kilometers along the stratum. After protection and excavation, the world's largest and most distinctive Jurassic original large-scale monolithic fossil display wall appeared in front of the world in 2017. Chongqing Yunyang Pu'an dinosaur fossil group was also approved by the National Paleontological Fossil Expert Committee. Identified as a world-class dinosaur fossil group.
Chongqing area is one of the important dinosaur fossil burial sites in China, but many of the previous excavation sites of dinosaur fossils were single sites, single skeletons or scattered fossils in a single era. location. The dinosaur fossils in the Pu'an dinosaurs in Chongqing have nearly 10,000 exposed fossils, including basic sauropods, sauropods, theropods, bird feet, stegosaurus, and plesiosaurs. , Turtles and other aquatic reptile fossils and invertebrate fossils represented by bivalves.
Why are there so many dinosaur fossils buried densely together? A preliminary analysis by Xu Xing, a researcher at the Chinese Academy of Sciences, believes that between 180 million and 160 million years ago, the Yunyang area was bordered by ancient lakes (Shu Lake in Cuba). Groups of different types of dinosaurs living near the lake suffered one or more sudden disasters. A large number of deaths occurred during the incident, and a large number of dinosaur bones drifting along with the water settled down to form fossils when the flow of rivers and rivers into the delta of the lake slowed down. Therefore, the dinosaur fossil site in Pu'an, Yunyang, Chongqing belongs to "off-site cluster burial". It is the corpse of many dinosaurs that died in different places, and was "carried" to the same area by mudslides and floods. This can also explain why the arrangement of fossils in the fossil group is relatively disordered, and the age span is particularly large. There are dinosaur fossils distributed in multiple formations in the early, middle and late stages of the Middle Jurassic.
Current research and excavations have shown that Chongqing Yunyang is another large dinosaur burial site in southwest China after Zigong in Sichuan and Lufeng in Yunnan. Relevant departments are planning to build a "Jurassic Park" centered on the Yunan Pu'an Dinosaur Fossil Group in Chongqing, allowing more tourists to experience the dinosaur-themed adventure in the park's dinosaur museum and dinosaur fossil remains.
(Reporter Zhang Guosheng correspondent Wang Binbin)