BEIJING, Aug. 13 (Xinhua) -- In the early Cretaceous Hami pterosaur fauna, which is about 130 million to 120 million years old in Xinjiang, China, the latest paleontologists' research has yielded another blockbuster result - the first time the fossils of large dinosaurs with a "cousin" relationship with pterosaurs have been found.
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Researcher Wang Xiaolin discussed with Dr. Qiu Rui (standing) of the Beijing Museum of Natural History, one of the authors of the paper, in his office. Photo by Sun Zifa, a reporter from China News Service
The Chinese and Brazilian cooperative team led by Wang Xiaolin, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (Institute of Paleovertebrates of the Chinese Academy of Sciences), for the first time, found 3 dinosaur fossils in the Hami Pterodactyl fauna, all of which belong to the porous vertebrates of the sauropod class, and the fossils are incomplete, respectively, preserving an associated cervical vertebra, an associated tail vertebra and a recommended vertebra, in addition, there is a theropod dinosaur tooth preserved with the tail vertebrae.
Fossil orthotype specimen of a Chinese Silk Road dragon. Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
Based on the characteristics of the cervical and caudal vertebrae, the cooperative team established two new genera and new species of dinosaurs, named "Chinese Silk Road Dragon" and "Xinjiang Hami Dragon", respectively, and the other section of the recommended vertebrae was not named because the fossils were too fragmented and the features were not obvious.
This is the first time that a sauropod porous vertebrate dinosaur has been found in the early Cretaceous strata of Xinjiang, and the first dinosaur fossil has been found in the Hami pterosaur fauna. The dinosaur research paper was published online on the night of August 12, Beijing time in Springer Nature's international academic journal Science Report.
Symbiotic preservation with Hami pterosaur fossils
Researcher Wang Xiaolin said that the latest research on dinosaur fossils was found by the Hami scientific expedition team of the Institute of Paleovertebrates of the Chinese Academy of Sciences in the Tu (Lufan) Ha (Mi) Basin underground Cretaceous Turgulu Qunsheng Jinkou Group, and coexisted with the Hami Pterodactyl fossils. Due to the long-term exposure of fossils to the Extremely Arid and Strong Aeolian Gobi Region, which was severely weathered and broken on the surface, the scientific expedition team carried out rescue collection in 2008, 2013 and 2016.
The Yadan landform of the site where the fossils were found. Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
The sauropods studied this time are the first non-pterosaur vertebrates found in the Hami pterosaur fauna, all produced in the equivalent layers of Hami pterosaur fossils, and the three dinosaur fossil specimens were produced about 2-5 kilometers apart.
Wang Xiaolin pointed out that due to the extremely serious weathering of the exposed surface of the fossils, only the remaining part of the broken vertebral body of the 3 dinosaur fossil specimens was rescued with Pilauk (gypsum pack), and the scientific expedition team technicians carried out scientific repairs on the other side of the surface that was still buried in the rock without exposure. After repair, it was shown that the three specimens were 6 associated cervical vertebrae and cervical ribs, 7 associated tail vertebrae and 1 segment of broken recommended vertebrae, of which the cervical vertebrae and tail vertebrae specimens were named Chinese Silk Road Dragon and Xinjiang Hami Dragon respectively.
The newly discovered dinosaur genera name originates from the fossil origin of Hami in Xinjiang, China, and the porous vertebrates are a huge sauropod dinosaur, and Hami is an important town in the "Belt and Road" economic belt, commemorating China's great Silk Road connecting the world since ancient times.
The Chinese Silk Road Dragon is more than 20 meters long
Wang Xiaolin said that the Chinese Silk Road Dragon has preserved 6 more complete cervical vertebrae associated with each other, namely the 10th-15th section, the length of a single cervical vertebra is between 455-540 mm, and the length of the 6 cervical vertebrae is about 3 meters, which is nearly 2 times the average length of the corresponding cervical vertebrae of the early Cretaceous Shishishi pan-footed dragon (body length of about 15 meters) found in Mengyin, Shandong, and conservative estimates are that the body length of the Chinese Silk Road Dragon is more than 20 meters.
The identification features of the Chinese Silk Road Dragon include the lateral ventral part of the posterior articular process-transverse septum of the middle and posterior cervical vertebrae, the anterior fork of the vertebral body-transverse post-diaphragm, the developed ventral flange of the parapragmatic-transverse septum, and the anterior and posterior contractions of the transverse process and the contact surface of the ribs of the middle and posterior cervical vertebrae.
Through detailed morphological observation, the research team found that the cervical vertebrae of the Chinese Silk Road Dragon had a thick superior-anterior articular process septum and a drooping neck rib, and compared with other discopods that preserved the cervical vertebrae, there were obvious differences in the orientation of the superior process-anterior articular process septum of the cervical spine, the direction of the anterior articular process-transverse process separator, and the degree of development of the lateral fovea of the cervical vertebral vertebra.
"Also preserved with the Chinese Silk Road dragon is a broken jaw of Hami Pterodactyl, indicating that these largeosaur dinosaurs lived with Hami Pterodactyl in the Cretaceous sky and land." Wang Xiaolin said.
Dinosaur fossils before collection. Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
The Xinjiang Hami dragon is significantly different from other dragons
Xinjiang Hamiosaurus preserves 7 associated tail vertebrae, namely the 4th-10th segment, the middle 5 segments are more complete, and the length of the single caudal vertebrae varies from 210-320 mm, which is about 1.5 times the average length of the corresponding tail vertebrae of the Late Cretaceous Post-Cretaceous Concave-tailed Dragon (body length about 12 meters) found in Mongolia, and its body length is conservatively estimated to be about 17 meters.
The identification characteristics of Xinjiang Hamiosaurus include: the sum of the height of the caudal crest and nerve arch is greater than the height of the vertebral body, the sagittal expansion of the vertebral arch of the anterior caudal vertebrae, the deep fossa of the posterior articular process septum and the transverse septum of the nerve spin, the transverse process of the anterior caudal vertebra pointing upwards, and the transverse process of the caudal vertebra sequence changing suddenly from pointing upwards to pointing downwards, without transition, etc.
Schematic diagram of the preservation of 3 dinosaur fossil bones (maurilio Oliveira). Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
Xinjiang Hamiosaurus is one of the few sauropod dinosaurs found in Asia, exhibiting unusual combinations of sauropods. By comparing the morphological characteristics of Xinjiang Hamiosaurus and other dragons in detail, the research team found that the length of the tail vertebrae of Xinjiang Hamiosaurus, the anterior concave tail vertebral body, the shape and direction of the ridge of the lateral side of the tail vertebrae near the abdomen, and the shape and direction of the transverse process were significantly different from other known dragons in East Asia.
In addition, along with the Xinjiang Hami dragon, there is also a theropod dinosaur tooth, which is also the first theropod dinosaur fossil found in the Hami pterosaur fauna. Wang Xiaolin said that because no tooth marks of theropod dinosaurs were found on the bones of the Hami dragon in Xinjiang, it is not possible to determine whether there is a phenomenon of theropod dinosaurs eating the corpses of the dragons. Sauropods were all four-legged plant-eating animals, and the discovery and study of these large plant-eating dinosaurs and carnivorous theropods will greatly increase the species and ecological diversity of the Hami pterosaur fauna.
Fossil orthotype specimen of Hami dragon in Xinjiang. Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
New fossil discoveries enrich the history of Chinese dinosaurs
Wang Xiaolin said that through phylogenetic analysis, the research team basically confirmed the taxonomic positions of the two new genera dinosaurs, the Chinese Silk Road Giant Dragon and the Xinjiang Hami Giant Dragon. To determine whether the newly discovered fossil cervical and caudal vertebrae belong to the same type, they analyzed the characteristics of the cervical and caudal vertebrae as a whole in two matrices, which constitute a sister group with the genus Discodata, but support this sister group only as characteristics of the cervical spine.
They then separated the characteristics of the cervical and caudal vertebrae as two types of analysis, the Chinese Silk Road dragon represented by the cervical vertebrae formed a sister group with the genus Panpodosaurus in the analysis of the two matrices, and there are multiple features to support, representing a close relationship with The Discopodactylosaurus, so the Chinese Silk Road Dragon belongs to the Pan-legged Dragon class.
The Xinjiang Hami dragon represented by the tail vertebrae is located in the dragon class in the analysis of the two matrices, but the addition of the Xinjiang Hami giant dragon makes the entire giant dragon class increase the unresolved multi-branch structure, and its own system position is not the same in the analysis of the two matrices, so its further system location cannot be confirmed at present, and new fossil materials and further research are needed.
In addition, the newly discovered dinosaur fossil specimen contains only 4 vertebrae and rib fragments, and due to the severe weathering fragmentation, it can only be confirmed that it belongs to the porous vertebrate class, which lived from the Late Jurassic to the Late Cretaceous 66 million years ago, due to the fact that it is less suitable for identification due to the weathering fragmentation.
Wang Xiaolin said that the three fossil specimens studied this time were found during a long-term field investigation of pterosaur research in the Tuha Basin by the Hami scientific expedition team, and it was also the first dinosaur fossil discovered in the Hami pterosaur fauna, which enriched the diversity of Mesozoic reptiles in the region and added new understanding to the research of Chinese dinosaurs, especially sauropod dinosaurs. The study of the Chinese Silk Road Dragon and the Xinjiang Hami Dragon not only increased the diversity of the Hami pterosaur fauna and the Chinese Early Cretaceous sauropod dinosaurs, but also provided new information for the evolution of this dinosaur taxon, and further supported the extensive diversity of Asian Early Cretaceous Porous Vertebrate Dinosaurs.
Ecological restoration map of the Chinese Silk Road Dragon (left) and the Xinjiang Hami Dragon (right) and Hami Pterodactyl fauna (Creation/Zhao Chuang, Scientific Guidance/Wang Xiaolin). Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
The Hami Pterodactyl fauna is the "Pterodactyl Eden"
Wang Xiaolin introduced that since 2006, the Hami scientific expedition team of the Institute of Paleovertebrates of the Chinese Academy of Sciences has been conducting scientific expeditions in the Hami Gobi for more than ten consecutive years, and found a rare Group of Hami Pterodactyl fauna, which has become the world's largest and most abundant pterosaur fossil production area, hundreds of millions of orders of magnitude Pterosaur once flourished here, is a veritable "Pterodactyl Eden".
It is understood that pterosaurs are not dinosaurs, but a type of flying reptile, but pterosaurs and dinosaurs are closely related, just like the "cousins" between humans, after differentiation from the same ancestor, pterosaurs flew to the blue sky, and dinosaurs dominated the land. In addition, pterosaurs and dinosaurs are extinct ancient reptiles that lived in the same era — about 230 million to 66 million years ago, from the late Triassic to the end of the Cretaceous.
Before the new research discovered the dinosaur fossils of "life and death", the Hami scientific expedition team of the Institute of Paleovertebrates of the Chinese Academy of Sciences has made a series of important achievements in the field of pterosaur research through more than ten years of scientific investigation and rescue collection, scientific repair and research:
Researcher Wang Xiaolin at the dinosaur fossil collection site. Photo courtesy of Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences
For the first time, three-dimensional preservation of hermaphrodites was found, and a large number of three-dimensional preserved pterosaur eggs and pterosaur embryos were found to coexist with them, among them, the world's first three-dimensional preservation of pterosaur eggs research revealed that Hami pterosaurs had a leather eggshell structure similar to the living reptile snake, showing that pterosaurs lived in groups; found a large number of juvenile to adult male and female pterosaurs, and named the first species in the Hami pterosaur fauna - Tianshan Hami pterosaur; found more than 200 pterosaur eggs, Embryonic and skeletal fossil trinity preservation of important specimens, of which 16 pterosaur eggs contain three-dimensional preservation of embryonic fossils, which is the world's first discovery of three-dimensional pterosaur embryos; through the study of bone histology and ontology including embryos and other bones, it was found that Hami pterosaur has a rapidly growing skeletal structure, belongs to the developmental mode of relatively precocious type, can not fly after birth, still need parental care, these discoveries and studies reveal the life history of this special flying reptile. These results were published in cover articles in Modern Biology and Science under the umbrella of Cell.
Wang Xiaolin believes that through years of field investigation and relevant evidence of burial, sedimentology and stratigraphy, these huge pterosaurs in Hami, Xinjiang, experienced many Cretaceous lake storm events, resulting in the death of their clusters and rapid burial.
He revealed that the follow-up work of the Hami scientific expedition team will strengthen the research of dinosaurs while conducting research on pterosaurs, and insist on studying, protecting and making good use of fossil origins. At present, it has assisted the local government to successfully apply for the Hami Pterodactyl-Yadan National Geopark, and is now actively promoting the construction of the Pterodactyl and Dinosaur Site Museum, "We hope that through the research of dinosaurs and pterosaurs in this place, the protection of sites and fossils, and the construction of the National Geopark and Site Museum, we can provide research and science education places for young people and make positive contributions to the development of local society, economy, culture and tourism." (End)
Source: China News Network