2020-11-05

New discovery by the Chinese Academy of Sciences team! Fossil”unicorn shrimp” more than 500 million years ago reveals the mystery of the origin of arthropods

By yqqlm yqqlm

   China Broadcasting Network, Beijing, November 5 (Reporter Sun Ying) At midnight on November 5, 2020, Beijing time, the British”Nature” magazine reported the discovery by the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences A kind of animal fossils that resembled shrimp more than 500 million years ago-“Zhang’s unicorn shrimp”. This is another major new scientific discovery in the”Chengjiang Fauna” in Yunnan, my country, adding empirical evidence to the theory of biological evolution.

   The”Chang’s Kirin Shrimp” discovered this time is also a giant predator from the ocean more than 500 million years ago” ” and the various characteristics of arthropods, known as the Cambrian”unicorn”, named”Zhang’s unicorn shrimp”, it is openThe transitional species of the mystery of the origin of the arthropod. Huang Diying, a researcher at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, said:“Arthropods are very common, such as centipedes, scorpions, beetles, ants, crabs, spiders, flies, mosquitoes, and crayfish around us. These are all arthropods. Specific characteristics? First, it has a hardening of the epidermis, called exoskeleton, and then its body is segmented, the limbs are also segmented, not only the antennae, but also the front appendages, especially the body has segments. The footsteps.”

   Life on earth has experienced a long evolutionary history of about 4 billion years. It was not until the Cambrian Era more than 500 million years ago that complex and diverse life suddenly appeared on the earth. This milestone major life evolution event is called”Cambrian Explosion“. Since Darwin, the”Cambrian Explosion” has been a major scientific puzzle that plagued the scientific community. Darwin specifically mentioned in his”Origin of Species” that the sudden appearance of complex animals in the Cambrian was a huge challenge to the theory of evolution.

   In 1984, the”Chengjiang Fauna” discovered in Yunnan by scientists from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences highlighted the suddenness of the”Cambrian explosion” and pushed the”Darwin’s confusion” To the vertex. Because the discovery of fossils in the Chengjiang fauna shows that, including vertebrates, almost all modern animal phylums appeared 520 million years ago (Figure 1). According to Darwin’s theory of evolution, in order to solve the mystery of the Cambrian explosion, scientists need to find the transitional ancestor fossils of the animal phylum origin.

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Tuyi Chengjiang Fauna Ecological Restoration (Drawing by Yang Dinghua)

   Chengjiang Among the fauna, the most diverse are arthropods. Huang Diying said:“How did these arthropods evolve from their ancestor types to true arthropods? We don’t know, because of the lack of a bridge, the’unicorn shrimp’ we discovered today is one of the odd shrimp and true arthropods. A transition type between the two.”

How did    arthropods evolve? What did their ancestors look like? This is a major problem in biological evolution, which has plagued generations of scientists for more than 100 years. Zhu Maoyan, a researcher at the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and head of the Cambrian Explosion Research Group, said:“Because arthropods are currently the most diverse life on our planet, they are also the most successful life. Where does one thing come from? To find a series of transitions of this evolutionary type, we discovered today that this’unicorn shrimp’ actually fills the gap.”

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Picture 2 Kirin shrimp fossil (photo courtesy Zeng Han)

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Picture 2 Kirin Shrimp fossil (photo courtesy of Zeng Han)

  What does the”unicorn shrimp” discovered this time look like? The research team conducted a detailed comparative anatomical study on the”unicorn shrimp” fossil and was able to restore the shape of the”unicorn shrimp” more than 500 million years ago. It is a rare chimeric animal. Zeng Han, assistant researcher at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and the first author of the paper, said:“The body of the’kylin shrimp’ has more than 20 sections. Each section has a pair of swimming paddle-like appendages and a pair of Legs for walking, its head is like a helmet, and there are 5 eyes on the front of the head, indicating that it should have a very keen vision. A pair of paw-like appendages covered with small thorns extend from the bottom of the head. So it should still be a predator. And it has so many swimming legs and limbs, indicating that it swims very fast. It integrates the body, appendages and head shells of true arthropods, as well as other predatory appendages. There are five eyes of the Cambrian monster Obabin sea scorpion.”

The    research team is based on years of accumulated research data, combined with the unique chimeric morphology and evolutionary developmental biology analysis of the”kylin shrimp” , Demonstrated the homology of the first pair of appendages between the strange shrimp and the true arthropod. The results show that the evolutionary position of the”unicorn shrimp” is between the strange shrimp and other true arthropods, and is located at the root of the true arthropods (Figure 4).

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 Picture Sanqilin Shrimp Recovery Picture (Drawing by Sun Jie)

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The new model of arthropod origin and early evolution revealed by the unicorn shrimp in Figure 4 (Zeng Han drawing)

  曾Han said:”During our submission process, international colleagues gave very positive comments. They said:’This perfect and unexpected transitional animal fills a knowledge gap in the evolution of arthropods.’ It stands up. An important transitional link in the evolution of arthropods covers the origins of several key shapes and innovations of arthropods. At the same time, it also’solves the controversial issue of the homology of early arthropod head appendages’.”

“Kirin shrimp” represents an important transitional fossil predicted by Darwin’s theory of evolution. It bridges the evolution from the strange shrimp to the true arthropod, fills in the key missing link in the origin of arthropods, and adds a powerful force to the theory of biological evolution. Of fossil evidence. For many years, Zhao Fangchen, a researcher at the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and the head of the Chengjiang Palaeontology Research Station, who has been persevering in finding many fossils, said:“Because we only speak the theory of evolution well before we can really talk about science. Because you have With the thought of evolution, you will be concerned about the changes in the surrounding things, and will continue to analyze all the things, animals, plants, and the connections around us, so why we engage in paleontology, this is also our biggest science goal and goal.”< /p>

   Zhan Renbin, director of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, said that research on the”Chengjiang Fauna” in Yunnan, China will continue to deepen. Zhan Renbin said:”Our country has advantages in this area, and the party group of the Academy also pays special attention to this work. We also have such strength. It can be expected that we will continue to have new breakthroughs.”