First confirmed! This part of the human body evolved from fish gills

The international academic journal "Frontiers in Ecology and Evolution" recently published the latest research results of scientists from China, Sweden and the United Kingdom, revealing for the first time that the human middle ear evolved from fish gills.

The first and second authors of this article are Gai Zhikun, a researcher at the Chinese Academy of Sciences, and Zhu Min, an academician of the Chinese Academy of Sciences. The third and fourth authors are Eric Elberg, an academician of the Royal Swedish Academy of Sciences, and Philip Donoghue, an academician of the Royal Society of the United Kingdom.

Gai Zhikun said that the middle ear is the secret of humans' sensitive hearing. There is now sufficient embryonic and fossil evidence to prove that the human middle ear evolved from the blowhole of fish.

But where did the blowholes come from? This question has puzzled the academic community for hundreds of years. Finally, scientists found clues to solve the mystery from fossils in China.

This is a 438 million-year-old skull fossil of a dawn fish found in Changxing, Zhejiang. Image provided by Gai Zhikun, a researcher at the Chinese Academy of Sciences

"In the past 20 years, our research team has discovered fossils of the more than 400 million-year-old dawn fish in Changxing, Zhejiang, and the broad-shelled turtle with complete gill filament impressions preserved in the first gill sac in Qujing, Yunnan, respectively, providing definite anatomical and fossil evidence that the blowholes of vertebrates originated from fish gills," said Gai Zhikun.

According to reports, these fossils were taken to the Swiss Light Source in Zurich, Switzerland for non-destructive scanning. Afterwards, 3D reconstruction software was used to perform a 3D virtual restoration of the skull of the dawn fish. A total of seven skull fossils of the dawn fish were reconstructed in 3D. In the skull, which is only the size of a fingernail, almost all brain regions, sensory organs, and nerve and blood vessel channels of the head of the dawn fish were reproduced.

This is a 410 million-year-old broad-shelled turtle fossil found in Qujing, Yunnan, which preserves the structure of the gill filaments. Image provided by Gai Zhikun, a researcher at the Chinese Academy of Sciences

Gai Zhikun said that the latest discovery explains why human ears and mouths are connected. What connects them is the breathing passage that ran from the fish blowholes through the mouths to the gills more than 400 million years ago.

"This is an evolutionary remnant left to humans by ancient fish. We now call it the Eustachian tube," said Gai Zhikun.

Source: Xinhua News Agency