China News Service, Beijing, September 27 (Reporter Sun Zifa) The Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (Institute of Paleontology, Chinese Academy of Sciences) announced on the 27th that the Xu Xing-Jinchangzhu Yanji project team of the Institute is in Yanji City, Jilin Province. In the middle Cretaceous strata of Longshan about 101 million years ago, the latest research has discovered the fossils of a new genus of new crocodile, Paraglus crocodile, named "Longshan Yanji crocodile" after the place of origin.
Stratigraphic information and excavation site of the Longjing Formation (picture from Paul Lamy, etc.).
Photo courtesy of Institute of Ancient Spine, Chinese Academy of Sciences
The Longshan Yanji crocodile is the second effective crocodile fossil found in Jilin after the Nong'an multi-wrinkled crocodile. It is important for understanding the evolution of primitive new crocodile to true crocodile and the evolution of existing Asian crocodile. significance.
At the same time, due to the fact that there are relatively few terrestrial strata in the mid-Cretaceous in the world, this will make Yanji a very important site for the international study of vertebrate groups in the mid-Cretaceous.
Longshan Yanji crocodile fossil orthodontic specimen and line drawing (picture from Paul Lamy et al.).
Photo courtesy of Institute of Ancient Spine, Chinese Academy of Sciences
Regarding the discovery of Longshan Yanji crocodile and related research results, Paul Lamy, a Ph.D. from the Institute of Paleospine, Chinese Academy of Sciences, and fellow scholars from China, the United States, Japan and other countries jointly completed the paper "New Genus and Species of Para-Alligator in the Middle Cretaceous Period in Jilin Province, Northeast China" , Recently published online by the international professional academic journal "Cretaceous Research".
Location map of Longshan Yanji crocodile system (picture from Paul Lamy, etc.).
Photo courtesy of Institute of Ancient Spine, Chinese Academy of Sciences
According to the Yanji project team of the Institute of Ancient Spine, Chinese Academy of Sciences, after continuous field work in recent years, a large number of vertebrate fossils have been discovered in Yanji, including dinosaurs, crocodiles, turtles and turtles.
The Longshan Yanji crocodile discovered in this latest study is a medium and large new crocodile fossil. Its main morphological features include: the frontal surface of the frontal bone has a raised wedge-shaped facade, and a transverse anterior orbital ridge has a groove crossing it. There is a middle ridge along the midline between the orbits, the inferior temporal arch is completely formed by the zygomatic/yoke bone, the elongated mandibular union is formed by the healed dentition, and the rear dentition of the mandibular fourth tooth has a tooth gap.
Compared with other Mesozoic biota, the research on Mesozoic crocodiles in China is still slightly insufficient. One of the main reasons is the insufficient number of collected fossil specimens and the poor preservation of most of them.
So far, most of China's crocodile-type fossils have been found in Jilin Province, especially the paraglyphs, which makes Jilin an important place in the paleogeographic distribution of Mesozoic crocodile-types.
A group photo of the field surgery team from the Institute of Ancient Spine of the Chinese Academy of Sciences working in the field (picture from Zhang Lizhao).
Photo courtesy of Institute of Ancient Spine, Chinese Academy of Sciences
According to the research classification, the Longshan Yanji crocodile belongs to the new crocodile.
Up to now, except for a few new genera and species found in North America and Brazil, the vast majority of alligators are found in Asia.
Most of the previous studies believed that the paradial crocodile did not belong to the real crocodile. Crocodile is a species.
Therefore, the discovery and research of Longshan Yanji crocodile is of great significance for understanding the evolution of primitive new crocodile to true crocodile, and for understanding the evolution of existing Asian crocodile.
In the past few decades, new crocodiles have received less attention, but this one has a lot to do with the origin of modern crocodiles.
The study of new crocodiles in the Mesozoic era is very important for understanding the biogeographic evolution of new crocodiles, the extent to which the diversity of new crocodiles is affected by climate, and the origin of modern crocodiles.
Longshan Yanji crocodile fossil orthographic specimen skull and line drawing (picture from Paul Lamy et al.).
Photo courtesy of Institute of Ancient Spine, Chinese Academy of Sciences
It is reported that the Yanji dinosaur fossil was first discovered in 2013 by the strange stone enthusiast Park Shengzhe on the banks of the Yangtze River. The Yanji fossil site in Longshan was determined by researcher Jin Changzhu in 2016.
In the same year, Jin Changzhu led many experts to investigate the Taiyang River. After identifying the Taiyanghe strata, they carried out tracing and paleontological investigations along the lithology of the relevant strata. Finally, a dinosaur fossil buried in situ and many other contemporaneous fossils were discovered at a construction site. Period of abundant biological burial.
The vertebrates at the Yanji fossil site lived in the middle of the Cretaceous about 101 million years ago. The fossil-producing strata are Longjing Formation, which is mainly composed of rivers and lakes alternately composed of gray-purple, gray-green, red-brown mudstone and sandstone. Facies deposition, combined with the study of other fossils in the discovered fauna, inferred that Yanji area was an ecological environment with warm and humid climate, high biodiversity, and rivers and lakes in the middle of the Cretaceous.
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