Scientists have discovered the world's smallest known snail in northeastern Borneo, which measures 0.5 to 0.6 mm, equivalent to the thickness of five human hairs placed next to each other. The snail has been named as Acmella nana. In fact, researchers have also found 47 other new species of land snails.

Study's lead researcher Menno Schilthuizen, a researcher at the Naturalis Biodiversity Center, said that they have also found a species, which has a very unique curlicue-shaped shell and has been named Ditropopsis davisoni.

It is yet to be known what the main function of the strange shell is. The researchers said that they had to search areas having outcroppings of limestone. It was a prerequisite because this rock has the calcium that is needed for snail's shell.

"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", affirmed Schilthuizen.

Before being found, all the snails have died owing to which researchers could not know everything they wanted to know about the animal's biology. The researchers said that it is not clear about what Acmella nana eats as they have not seen them alive in the wild.

Many of these limestone hills are being quarried for cement, and Schilthuizen and his colleagues have already documented native snail species that have gone extinct after their entire habitats were destroyed. Perhaps, he said, these companies could quarry just part of a hill and leave the other part untouched to promote the continuation of these species.

Some of the new 48 species described in the present paper are widespread in Borneo and had been familiar to the team of snail researchers for decades. Yet, they had not got round to naming them until now. Others eke out a hidden existence on mountain tops or in rare vegetation types and, therefore, were only recently discovered by the authors.

The new information tells us more about isolated, or endemic, species such as the new record-holder. Moving so slowly, snails can easily get stuck in very small patches of a habitat. There they can spend long enough to evolve and adapt to the particular limited area, undisturbed by the rest of the world.

Snails play an important ecological role, feeding on dead and decaying matter, Schilthuizen said.

The world's tiniest snail has a shell of merely 0.50 - 0.60 mm width and 0.60 - 0.79 mm height. The previous holder of the title of world's smallest snail, the Chinese Angustopila dominikae, published earlier this year.

The new record holder can be found at three places in Malaysian Borneo -- Malaysia, Brunei and Indonesia.