How did arthropods evolve? What did their ancestors look like? The 100-year-old mystery of this biological evolution may have been solved by Chinese scientists. Recently, the research team of Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences discovered for the first time in the world a shrimp-shaped fossil more than 500 million years ago: it looks strange, with five eyes, both the predatory appendages of the marine giant predator odd shrimp, and the hardened skins, healing headshells, multiple torsos and sectional leg limbs of arthropods such as the mosquito shrimp crab.
Reporter: Chen Lei
Because its body is embedded with a variety of animal morphological characteristics, just like the traditional Chinese myth of the Rui beast – Kirin, so it was named “Zhang’s Kirin shrimp.”
Kirin shrimp fossils. Zeng provided the picture
The fossils of these Kirin shrimps, discovered by Chinese scientists in the Cammatic stratum, fill a key missing link in the origin of arthropods and will solve the 100-year-old mystery of the biological evolution of arthropod origin. The latest research was published in the journal Nature on November 5, Beijing time.
“This is another important discovery in our study of the Chengjiang herd, and the Kirin shrimp represents an important transitional species predicted by Darwin’s theory of evolution, which provides a bridge between the evolution of odd shrimps to real arthropods, adding a powerful fossil evidence to the theory of biological evolution.” Zhu Maoyan, head of the Camdhan Outbreak Research Group, which published the paper, said.
Kirin shrimp fossils. Science and Technology Daily reporter Chen Leizheng
A scientific puzzle of the Camurai outbreak
Earth life has a long history of about 4 billion years, why did it not appear on Earth until the Camura era more than 500 million years ago, when complex and diverse life suddenly appeared on Earth? Since Darwin, the Cammass Outbreak, a major life-evolving event, has been a major scientific mystery that has plagued the scientific community. In his Origin of Species, Darwin specifically mentioned that the sudden emergence of complex animals in the Camance was a great challenge to evolution.
“In 1984, scientists at our institute discovered the Chengjiang swarm in Yunnan, highlighting the suddenness of the Camburst outbreak and pushing Darwin’s confusion to its peak.” The paper’s co-author, Researcher Huang Diying, explains that fossil discoveries in chengjiang’s animal population suggest that almost all modern animal species, including vertebrates, appeared 520 million years ago. According to Darwinian evolution, to solve the mystery of the Cambic eruption, scientists need to find transitional ancestral fossils of the origin of animals such as ancestral birds. “
Ecological restoration of Chengjiang animal herds. Yang Dinghua drawing
To fill the missing link in the origin process of arthropods
Among the Chengjiang animal groups, the most diverse are arthropods.
“Since the Camburo outbreak, arthropods have been one of the most successful animals on Earth and the largest number of individual animals on Earth today.” According to the paper’s first author, Dr. Zeng Wei, “arthropods have features such as skin cirrhosis, body sections, appendication sections, etc., which account for about 80% of the species diversity in the animal world and conquer ‘land, sea and air’.” Butterflies, crabs, dragonflies and spiders as we know them are arthropods. “
But the origins of arthropods have remained a mystery and have plagued generations of scientists. “The evolutionary relationship between Camarilla arthropods is inconclusive.” Zeng said.
“In the Chengjiang animal population, qi shrimp is the top predator of the Cammatic era, up to two meters in length, and is considered to be the ancestral type of arthropods. However, there is a huge difference between the forms of odd shrimp and real arthropods, and there is an evolutionary gap between the two that is difficult to bridge. This chasm has become a key missing link in the exploration of the ‘mystery of the origin of arthropods’. Zhao Fangchen, the paper’s author and director of the Chengjiang Paleontical Research Station, said.
Kirin shrimp, embedded in a variety of animal forms of the “four unlike”
Zeng said the team found six rare shrimp-shaped fossils in chengjiang animal group, with a maximum of 7 cm and a minimum of only 1 cm. Using a variety of techniques, the researchers conducted a detailed comparative anatomical study of the fossils to restore their 500 million-year-old form.
The animal’s body has obvious real arthropod characteristics, such as hardened skin, healed head shell, multiple torsos, and subseeded legs. However, its head is embedded with the morphological structure of the arthropod ancestral type, including the cambic monster “Opabin Sea Scorpion” unique to the five eyes, as well as the predatory appendages of the odd shrimp. Therefore, it combines the physical characteristics of the ancestral types of real arthropods and arthropods, and is a rare “four-unlike” chimed animal. It’s like Kirin, so it’s named.
Kirin shrimp recovery map. Huang Diying is pictured
But to determine where the Kirin shrimp is in the evolutionary process, it is necessary to go through scientific data analysis and calculation. Based on the research data accumulated over the years, they demonstrated the entology of the first pair of appendages of odd shrimp and real arthropods on the basis of the unique inlay morphology and evolutionary developmental biology analysis of Kirin shrimp. Through genealogy reconstruction, a new model of the evolutionary relationship and appendication morphological transformation of anti-performance early arthropods was calculated. The results show that the evolutionary position of Kirin shrimp is between odd shrimp and other real arthropods and at the root of real arthropods.
Kirin shrimp reveals new patterns of arthropod origin and early evolution. Has been sketching
Missing gaps in the evolution of arthropods have been filled, and experts reviewing the study argue that “this perfect and unexpected transitional animal fills a knowledge gap in the evolutionary history of arthropods”.