Those interested in paleontology should know that the Mesozoic Era was an era of reptile flourishing represented by dinosaurs. The Cenozoic era was an era of mammalian dominance. However, whether there were mammals in the age of the dinosaurs has been debated in the academic community before. Around 2007, paleontologists made an unexpected discovery in the fossil strata of Qiupu Township, Luanchuan County, our city, and settled down in the debate.
<h1 class="pgc-h-arrow-right" > the exposed red soil layer, giving experts an unexpected discovery</h1>
Today, walking in the mountains and ravines around Qiupu Township in Luanchuan County, even a geographical "xiaobai" can try to find traces of fossil strata - the unique red soil layer is the most obvious marker.
Red soils are mostly found in tropical areas and appear red due to their abundance of iron. In general, the northern layers of red soil are located deep underground. However, due to an orogeny in the Cenozoic Era, the strata here in Luanchuan were constantly rising and breaking, leaving the red soil layer bare to the surface, which contained various paleontological fossils, and was therefore discovered. These fossils have long been used as medicinal herbs by the ancients, and it was not until the progress of modern science that people gradually understood its origin.
Around 2007, our city was a sensation due to the discovery of a large number of dinosaur fossils. At that time, the experts of the former Henan Provincial Geological Museum were stationed in Qiupu Township for a long time, and round after round of exploration and excavation of the fossil strata here were carried out. In the meantime, they dug up a large number of paleontological fossils.
Jia Songhai, director of the Paleontology Research Office of the Henan Museum of Natural History, said that in most cases, the dinosaur fossils that were just unearthed were very messy and difficult to identify. If you want to carry out further research on it, the first work to do is to classify and sort the fossils, and stitch them together to restore them. It is in this process that experts have discovered one new genus of dinosaurs after another, such as Luoyang Zhongyuan Dragon, Henan Luanchuan Robber Dragon, Henan Autumn PickpocketOsaurus, Mini Yu Dragon, and Zhang's Autumn Pickpocket Dragon.
However, at that time, no one thought that when sorting out a pile of dinosaur fossils, a bunch of inconspicuous paleontological fossils would attract the world's attention in the future.
<h1 class = "pgc-h-arrow-right" > judging by teeth that the fossil came from a mammal</h1>
Jia Songhai said that after their fossils were spliced and restored, it was preliminarily judged that this was a paleontology that was not a dinosaur fossil, but a mammal.
Mammals have many characteristics, such as they have a high metabolic rate; body temperature remains constant; limbs are protruding downwards; embryos develop in the mother's body; the mother feeds the pups with milk... However, most of the above characteristics of mammals are difficult to express in fossils. Therefore, for paleontologists, to determine whether a fossil is mammalian or reptile, most of them still have to rely on teeth and bones to distinguish.
The tooth morphology of mammals is quite different from that of reptiles. Most reptile teeth are in the same form, either all conical or all leaf-shaped, but mammalian teeth have a differentiation of incisors, canine teeth, premolars and molars, suitable for different functions, such as grasping, puncture, cutting, grinding, etc. Due to differences in food and behavior, the tooth morphology of different groups of mammals is also very different, so scientists can infer the category of mammals and even specific to the classification of genera and species by observing and studying fossil teeth.
Because the fossil paleontology was so well preserved, with intact teeth and bones, experts quickly determined that it was a polyodont, a mammal that looked like a rodent.
< h1 class= "pgc-h-arrow-right" > its discovery, strongly demonstrating the existence of mammals in the Mesozoic Era</h1>
Experts have found many interesting phenomena in this polyodont. For example, experts found that the premolars of this polyodontum have the replacement of deciduous teeth and permanent teeth, indicating that this is a polyodont that is not very old, and is changing teeth This is the first direct evidence of tooth replacement found in polyodontic fossils, which is helpful to understand the evolution of teeth of polyodonts and mammals.
In addition, experts also found that this polyododont experienced an accident as a child, which caused the right leg tibia fracture fracture and dislocation. "Although the injuries were severe, making it more difficult to forage and escape predators, they were not fatal to plant-fed or omnivorous polyodontics; moreover, the amputated limbs of the Yujun beasts healed slowly under natural conditions and partially restored the function of supporting the body." Jia Songhai said that this fossil record is very rare and is the first case of severed limb paleopathology found in Mesozoic mammals.
In 2015, the related paper was published in the journal Nature, naming this polyodont as Zhongyuan Yujun. Experts speculate according to fossils that the restored Central Plains Yujun beast is 40 cm long, about 20 cm high, weighs about 3 kg, and is the largest known Mesozoic polynodontate in Eurasia. Due to the limited information transmitted by the fossils, the gender of this Central Plains Yujun beast cannot be distinguished.
In 2018, the "International Symposium on Mesozoic Mammals" was held in Beijing, where paleontologists from the United States, Canada, the United Kingdom, Germany, Russia and China gathered to discuss the theme of "New Evidence and Interpretation of Mesozoic Mammal Evolution", focusing on breakthroughs in the evolution of Mesozoic mammals.
When the experts present saw the fossils of the Central Plains Yujun beast from Luanchuan, they said, "The well-preserved fossils of the Central Plains Yujun beast are rare in the world, and its discovery is an important specimen in the study of Mammals in the Mesozoic Era, which strongly proves the fact that mammals exist in the Mesozoic Era." ”
Fossils of the Central Plains Yujun beast
Restoration of the Central Plains Yujun Beast
(Luo Bao Rong Media reporter Liu Jiayi )