The variation curve of organic carbon isotope in the composite profile of Yiliang Dahe river and the chemical stratigraphy comparison with the classical SDB profile at home and abroad. Courtesy of Zhao Wenjin
Beijing, July 27 (China News Network) -- The Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (Institute of Paleovertebrates of the Chinese Academy of Sciences) released a news release on the 27th that the early vertebrate research team of the Institute of Science and Technology of the Institute and the State Key Laboratory of Marine Geology of the University of Science and Technology of China and Tongji University jointly completed the latest research results, saying that the differentiation of the empty spiny fish-fanfin fish and the lungfish-tetrapods should occur between 427 million and 416 million years ago.
Phylogeneal and geohistoric distribution of flesh-fin fish clades , including living echinoflora , lungfish , and tetrapods. Courtesy of Zhao Wenjin
The new progress paper by Chinese scientists in the field of the Silurian-Devonian Boundary (SDB) in South China on the "Minimum Time Constraint of the Divergence Point of the Silurian-Devonian Boundary and the Lungfish-Tetrapod Divergence Point" in Eastern Yunnan has recently been published online in chinese and English editions of Science in China: Earth Science. Zhao Wenjin, researcher of the Institute of Paleovertebrates of the Chinese Academy of Sciences, and Associate Professor Zhang Xiaolin of the School of Earth and Space Sciences of the University of Science and Technology of China are the co-first authors of the paper, and Zhu Min, researcher of the Institute of Paleovertebrates of the Chinese Academy of Sciences, is the corresponding author of the paper.
According to the early vertebrate research team of the Institute of Paleovertebrates of the Chinese Academy of Sciences, the latest research results mainly carry out detailed research on the sequence of continuous Silurian-Devonian boundaries in the Yiliang River area of Eastern Yunnan, and carry out detailed research on carbon-stable isotope chemical stratigraphy, obtain reliable geochemical indicators, and determine the location of the Silurian-Devonian boundaries in the Dahe region.
There were phylogenetic and geological distributions of jaws during the Early Devonian-Devonian period. Courtesy of Zhao Wenjin
The diversity of early finfish fossils is very high in southern China, especially in eastern Yunnan, and its fossil record shows that the earliest representatives of important finfish branches also appeared in Yunnan. The determination of the Silurian-Devonian boundary in the Great River Region and the establishment of the existing paleontological data and biological strata fossil belts in eastern Yunnan provide key data for clarifying the geological age of fish-bearing strata in eastern Yunnan, which is very helpful for more accurate calibration of the minimum and maximum estimation times of the divergence points of the empty spiny fish-fanfin fish and the lungfish-tetrapods.
According to the research team, lungfish-like Yang's fish from the Yunnan Dongxi Shancun Formation and Xitun Formation are generally considered to be the oldest representatives of the fanfin fish crown group and the meatfin fish crown group, and the fanfin fish crown group excluded from the empty spiny fish mainly includes lungfish and tetrapods. Sister taxa of the oldest known carnivorous fish crowns, such as spotted scales and ghost fish, have been reported in the Ludford order of the Silurian Rhodrodom. Therefore, the distinctions of echino-fanfin fish and lungfish-tetrapods should both occur within the Rhodesch-Lochkov interval, which means that the minimum estimated time of the two divergence points should be at least 416 million years ago and the maximum estimated time should be about 427 million years ago, that is, the distinction between empty spiny fish and lungfish-tetrapods should occur between 427 million and 416 million years ago.
Experts point out that the Silurian-Devonian line is the first line between departments to use modern stratigraphic methods and procedures for systematic research. The determination of the exact location of the Silurian-Devonian boundary in Eastern Yunnan has both global stratigraphic comparative significance and directly affects the estimation of the minimum and maximum time constraints of the lungfish-tetrapod divergence points. (End)
Source: China News Network