To solve the mystery of the origin of arthropods, my scientist discovered the fossil of "unicorn shrimp"
Science and Technology Daily (Reporter Chen Lei) How did arthropods evolve?
What did their ancestors look like?
This century-old puzzle of biological evolution may be solved by Chinese scientists.
Recently, a scientific research team from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences discovered for the first time a shrimp-shaped fossil more than 500 million years ago in the world. It has a strange appearance, five eyes, and a body with a variety of animal morphological features.
This transitional species was named "Zhang's Kirin Shrimp". It is another major scientific discovery of the Chengjiang fauna in Yunnan, my country. It provides important fossil evidence to answer the "mystery of the origin of arthropods" and adds empirical evidence to the theory of biological evolution.
On November 5, the "Nature" magazine published the results of this research.
Since the Cambrian outbreak, arthropods have been one of the most successful animals on earth.
The well-known butterflies, crabs, centipedes, and spiders are all arthropods, which occupy approximately 80% of the species diversity in the animal kingdom today.
However, the origin of arthropods has always been a mystery, and there are key missing links in its evolution. For example, the morphological differences between the primitive ancestors of arthropods and true arthropods are huge, and there is a difficult evolutionary gap between the two.
The unicorn shrimp discovered by the Cambrian outbreak research team led by researcher Zhu Maoyan filled this important evolutionary gap.
The body of the unicorn shrimp has obvious characteristics of a true arthropod, such as a hardened epidermis, a healed head shell, a multi-segmented trunk, and segmented legs.
However, its head is also embedded with the morphological structure of the arthropod ancestor type, including the five eyes unique to the Cambrian monster "Opabin Sea Scorpion", and the predatory nature of the Cambrian giant top predator strange shrimp Appendage.
Therefore, the unicorn shrimp combines the physical characteristics of the true arthropod and the arthropod ancestor type, and is a rare "four-unlike" chimeric animal.
The research team conducted a detailed comparative anatomical study on the unicorn shrimp fossil.
Based on the accumulated research data for many years, combined with the unique chimeric morphology and evolutionary developmental biology analysis of the unicorn shrimp, the homology of the first pair of appendages between the strange shrimp and the true arthropod was demonstrated.
The results show that the evolution position of the unicorn shrimp is between the odd shrimp and other true arthropods, and is located at the root of the true arthropod.
Like Archaeopteryx, the unicorn shrimp represents an important transitional species predicted by Darwin’s theory of evolution. It bridges the evolution from the strange shrimp to the true arthropod. The paper reviewer believes that “this is a perfect and unexpected transitional animal. It fills a knowledge gap in the history of arthropod evolution."