Chinese scientists have studied and confirmed that Yunnan worms are the most primitive vertebrates

Recently, Chinese scientists have found that Yunnan worms produced by the Cambrian Ji Chengjiang animal group 518 billion years ago have its "eloquent bow" with the unique cell cartilage structure of vertebrates, which confirms that Yunnan worms are the most primitive of vertebrates. Class group. The result was published today (July 8) in the international academic journal "Science".

The study was completed by the research team of "Early Early Evolution of Life System" led by Researcher Zhu Maoyan Researcher Zhu Maoyan Institute of the Institute of Geology of the Chinese Academy of Sciences and Professor Jiang Baoyu of the School of Earth Science and Engineering of Nanjing University. They used a variety of modern experimental technical means such as three -dimensional X -ray faults to scan microscope, Fourier infrared spectrum, Raman spectrum, scanning electron microscope, and transmitted electron microscope to crack this mystery from a micro anatomy structure.

Based on the scientists, the Yunnan worm gill bow that scientists have proposed in 2003 may have an important clue of cell cartilage, and analyzed the gill bow structure of 127 Yunnan worm specimens produced in Haikou. A micro -nano -saved stacked plate -shaped cell structure and protein micro -original fiber structure. The stacked cell structure is a unique arrangement of cartilage cells, while protein microman fiber is a fiber structure of vertebrate cartilage common cell matrix. These two features prove that Yunnan worms have a unique pharyngeal bow that is unique to vertebrates and composed of cell cartilage, indicating that Yunnan worms belong to the original vertebrate.

In order to further determine the specific evolution of the Yunnan worm, the research team has integrated the latest trait matrix, including rear animals and early vertebrate fossils, and increases the newly observed characteristic information of Yunnan worms. Reconstruction calculation. The analysis results confirmed that the Yunnan worm is in the most foundation of the vertebrate spectrum, between tails and other vertebrates (including existing and fossil species).

For the first pair of swallow bows that were controversially controversial in Yunnan worms, the research team found the first pair of swallow bowls in the new specimen. The structure of micro -original fiber. Therefore, Yunnan worms have 7 pairs of swallow bows with similar to each other and have cell cartilage. The discovery of the 7 -pair of pharyngeal bows in Yunnan insects supports the theoretical hypothesis of vertebral animal pharyngeal arow as early as the 19th century as early as the 19th century.

In addition, the research team's research also found that the 7 -pair of swallow bows of Yunnan worms connected at the pair of horizontal cartilage at both ends of the abdomen, forming a basket -like throat. (The throat is a set of bone slices around the head of the vertebrate head of the vertebrate, which plays a role in supporting and protecting. The pharynx of the existing vertebrates consists of the bones of the swallow bow, the tongue, and the gill bow.) Basic pharynx is a typical feature of existing jaw -free vertebrates and fossil -free jaws. Composition of cartilage sticks. The throat characteristics of Sprig fish after the Sprig fish caused controversy about vertebrate ancestral throat shape. Earlier, the characteristic of Yunnan worm pharyngeal cranial in the foundation of vertebrates, supporting the more ancient ancestral characteristics.

It can be seen that, as the oldest close relatives of existing vertebrates, Yunnan worms provide key evidence to reveal the origin and early evolution of vertebrates, and the exploration of the evolution of vertebrate jaw and other key features will have a profound impact. From another perspective, the research once again shows the potential of the Chengjiang animal group fossils with the preservation of fine -scale biological structures.

Source: CCTV News Client

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