The legendary snail that disappeared for a century reappears in the world!

Recently, Chinese researchers discovered sessile freshwater snails that had disappeared for a hundred years .

On rocks in rivers in Hechi and Guiping, Guangxi Zhuang Autonomous Region, researchers have discovered a unique Chinese freshwater snail species, the river spiral snail, which has disappeared for more than a hundred years. This research result was recently published in the international academic journal Proceedings of the Royal Society B, Biological Sciences.

Zhang Lejia, co-first author of the paper and a doctor at the Natural History Museum in Berlin, Germany, is currently conducting snail research in Kunming, Yunnan. He introduced that the river snails unique to China are the only freshwater snails in the world with autonomous fixation habits, and can be firmly fixed on the surface of rocks like oysters in seawater. However, since the discovery of the Chinese river snails was published by the French more than a hundred years ago, this unique group has never been collected and reported.

(Left) A living male Liu's spiral snail climbing on a female Liu's spiral snail fixed on a rock (Photo by Shi Ziang), (Top right) Shell of a female Liu's spiral snail (Photo by Zhang Lejia), (Bottom right) Shell of a male Liu's spiral snail (Photo by Chen Zheyu).

The study was jointly completed by researchers from the Berlin Museum of Natural History, Peking University and other institutions. After discovering this group that had disappeared for a century on the limestone in Longjiang, Qianjiang and Xunjiang in Guangxi, the researchers named this new species Liu's river spiral based on molecular systematics, morphology and anatomy, and conducted research on its unique fixation habits and sexual dimorphism.

Studies have shown that only female Liu's river snails have the habit of attaching to rocks. Due to the attachment, their original shell opening is closed and they cannot move freely. Female Liu's river snails have developed a second shell opening for physiological activities such as eating, excretion, and mating. Male Liu's river snails can move freely, have the morphology of general snails and a unique shell opening, which makes it easier for them to find female Liu's river snails to mate and reproduce. Comprehensive molecular and morphological studies have confirmed that Liu's river snails are a new species different from Chinese river snails, and once again confirmed that the genus River Snail should be classified in the family of Bean Snails.

There are stones with Chinese river spiral snails attached to them. The red frame is the selected type specimen. (Photo by Zhang Lejia)

According to the researchers, the habit of clinging to rocks is an adaptive evolution of the river snails to the limestone environment in the rapid rivers of Guangxi, which makes them a dominant species in this habitat; however, the habit of clinging to rocks and being unable to move is a great disadvantage for survival and reproduction, so the river snails have also evolved a second shell opening that is unique among mollusks and extreme sexual dimorphism. The researchers believe that the river snails are an excellent example for in-depth research on species adaptive evolution and evolutionary innovation.

At the same time, the researchers pointed out that since the river environment where the river snail lives is very close to densely populated areas and hydropower stations, the survival of this unique species unique to China is easily affected by human factors and urgently needs special attention and protection.

Planning and production

Source: Xinhua News Agency

Editor: Zhong Yanping