Researchers have discovered 48 different species of snails including the smallest one yet, the Acmella nana.

An expert team made up by Dutch and Malaysian researchers has gone and returned from Borneo, an island in Southeast Asia’s Malay Archipelago which is shared between Malaysia, Brunei and Indonesia. In their time spent there, they have discovered 48 different species of snails. Moving the former record-holder, the Chine Angustopila dominikae, one step down is the Acmella nana, a snail with an average height of 0.6 milimeters.

With its white, translucent shell, the newly discovered snail is now the smallest snail in the world. So small, in fact, that the investigators couldn’t have found it without a microscope while walking around the island.

The world’s smallest land snail Acmella nana. Credit: Prof. Dr. Menno Schilthuizen, Naturalis Biodiversity Center

However, the group knew where and how to find the unknown mollusks. Because snails’ shells are made of calcium carbonate, they are likely to live in Borneo’s limestone hills. Menno Schilthuizen, a professor of evolution at Leiden University in the Netherlands and lead author of the study explained the process of the hunt: “When we go to a limestone hill, we just bring some strong plastic bags, and we collect a lot of soil and litter and dirt from underneath the limestone cliffs, we sieve the contents, and dump the larger objects, including the snail shells into a bucket of water. We stir it around a lot so that the sand and clay sinks to the bottom, but the shells— which contain a bubble of air — float”. Afterwards, they take out the floating shells and inspect them under a microscope.

It’s still unknown what the Acmella nana eats since the scientists haven’t seen it alive. However, they believe that it may live very much like a related species called the Acmella polita, which feeds of thin layers of bacteria and fungi that grow on the limestone caves surfaces. It is also very likely that Acmella nana has gills. The claim is due to a door-like structure called operculum. This is particular of snails which possess water-breathing organs.

Aside from finding the smallest snail and 47 other species, the team also discovered a curlicue-shaped shell snail. Schilthuizen said that the researchers don’t know what this shell’s function is. They state that it’s uncommon for a land snail, seeing as it relates to fragileness.

Borneo is famous and known by biology scientists due to it’s large biodiversity in such small space. “Because tiny snails can cover so little ground, they evolve rather specific adaptations for their small patches of habitat. The phenomenon makes them a unique example of the nuances of biodiversity, but also quite ecologically vulnerable,” said Schilthuizen.

Sources: Live Science