China News Service, Beijing, July 14 (Reporter Sun Zifa) In the field of ancient animal evolution, the traditional view has always been that the extinct cylindrical tooth rat originated in North America. However, the international cooperation team led by scientists from the Institute of Paleontology and Paleontology of the Chinese Academy of Sciences (Institute of Paleontology of the Chinese Academy of Sciences) recently discovered the earliest known evidence of rodent fossil rodents in Asia in Inner Mongolia, and believed that more primitive cylindrical teeth were found in Asia The possibility of rodents.
The reporter learned from the Institute of Paleontology of the Chinese Academy of Sciences on the 14th that Researcher Li Qian of the Institute has recently published articles in the international professional academic journals "Journal of Vertebrate Paleontology", "Palaeobiodiversity and Palaeoenvironments" and In the "Journal of Ancient Vertebrates", a number of research papers published by the international cooperation team on the cylindrical tooth rat fossils in the Erlian Basin, Inner Mongolia were published online.
Gobi cylindrical tooth rat fossil material. Photo courtesy of the scientific research team
Researcher Li Qian introduced that Cylindrosaurus is an extinct, semi-burrowing or burrowing rodent, distributed in Asia and North America. Fossils are the most abundant in North America, from the Lower Eocene to the Upper Oligocene. Have found. In the past, a large number of studies on cylindrical dents have focused on North America, and there have been sporadic reports in Asia in recent years. Therefore, it has long been believed that North America is the origin and main habitat of this type of animal.
Since 2005, an international cooperation team led by Researcher Wang Yuanqing of the Institute of Ancient Spine of the Chinese Academy of Sciences has conducted a comprehensive survey of the Erlian Basin in Inner Mongolia for more than ten years, including rock, biological, isotope and magnetic stratigraphy. Through years of accumulation, a variety of rodent fossil materials from different eras have been discovered in the Erlian Basin.
The enamel analysis of Gobi cylinder tooth stomata. Photo courtesy of the scientific research team
Among them, the Gobi cylindrical tooth rat found on the Ulausuxi section was determined to be in the backbone position of the cylindrical tooth rat through morphological and phylogenetic studies, and it is the most primitive cylindrical tooth rat known in Asia. The discovery of the Gobi cylindrical tooth rat not only provides new fossil evidence for the evolution of the early cylindrical tooth rodents in Asia, but also brings new considerations to the origin of the cylindrical tooth rodents.
The international cooperation team also found Gobi cylindrical squirrels, original squirrel squirrels, false squirrel squirrels, and squirrel squirrels in the middle and late Eocene strata at the Erden Aobao section and Yihe Subu site. The Yihesubu pseudo-cylindrical rat discovered in the Late Eocene strata is the first primitive pseudo-cylindrical rat discovered in China and the most primitive known in Asia.
Cylindrical phylogenetic analysis. Photo courtesy of the scientific research team
The research team believes that the different types of rodent rodents found in different layers in the Erlian Basin in Inner Mongolia indicate that the rodent rodents may have a relatively continuous evolutionary sequence in Asia, as well as the rodent rodents in North America and Asia. Migration and exchange studies between the two continents provide new evidence.
Yihe Subu pseudo-cylindrical rodent fossil material. Photo courtesy of the scientific research team
"It is safe to say that the origin and diffusion of Cylindrix rodents are more complicated than previously understood. The discovery of more and more Cylindrical rodents fossils in Asia is important for solving their origins and the communication between different continents. Status." Li Qian said. (Finish)