Two new land snail species were discovered by scientists in a cave in northern Vietnam and in a limestone gorge in northern Laos-becoming the world's new smallest land snail species. Scientists described the discovered snail species to be tinier than grains of sand.

The new smallest land snail species named, Angustopila psammion or A. psammion, was discovered by scientists in a cave in northern Vietnam.

Meanwhile, the second smallest land snail species named, A. coprologos, wasdiscovered in a limestone gorge in northern Laos.

The Two Most Smallest Land Snail Species

(Photo : Mohd Rasfan via Getty Images)

The discovery of the new snail species were published in the journal Contributions to Zoology on January 5. "It's amazing how small they are-we wouldn't have expected that," says Adrienne Jochum, a researcher with Natural History Museum Bern in Switzerland, as per National Geographic.

The name 'Psammion' from the newly discovered A. psammion land snail species derives from the ancient Greek word for 'grain of sand,' as per National Geographic.

On the other hand, the other snail species A. coprologis was derived from the Greek word 'dung gatherer.' The previous holder of the world's smallest land snail was the Acmella nana, discovered in Borneo in 2015,

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Scientific Expeditions in Vietnam and Laos

During the two expeditions in Southeast Asia, co-authors of the study András Hunyadi, Jaap Vermeulen, and Katja Anker, had collected the snails' shells from the soil at the base of limestone rocks and inside the caves.

The shells were then placed in a bucket of water and dried up. The scientists said the locations support a wide diversity of tiny snails due to the limestone geology of the habitat.

Due to the size of both the snail species, the scientists used a special digital microscope to scan and observe the shells. The scientists imaged the shells through electron microscope images.

The study's scientists speculate that the size of the snails probably allowed them to escape from predators by resorting within the cracks of rocks, or root surfaces.

In spite of these survival advantages, Timothy Pearce, a snail researcher at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, stated these small snails face the challenge of producing eggs, which must fit through their shells.

The snails' organs such as their brains, hearts, and lungs must also fit their shells, says Pearce.

Micro-Sized World

While the two newly discovered snails are the smallest on land among their species, several sea snails are even tinier than them-with the smallest of them named, Ammonicera minortalis Rolán, discovered in 1992, as per the World Register of Marine Species.  

Following the expeditions in Vietnam and Laos, Jochum acknowledged the fact that there is so much more to discover when it comes to species in the micro-sized world, as per National Geographic.

The study sheds light on the probability that there may be other tiny snail species that scientists have not discovered.

Related article: Borneo Snails Break Record For Smallest Land Snail Species, Researchers Say