Just when you thought that snails couldn’t get any smaller, a group of Dutch and Malaysian researchers have discovered a new species that now claims the title of the world’s tiniest snail. The shiny, white, translucent shell of the new species Acmella nana measures just 0.7mm in diameter. It broke the previous record of Angustopila dominikae that was found in China in September. It is now the second smallest snail with a diameter of 0.86mm.
48 new species discovered in Borneo
Specimens of A. nana were discovered along with 47 other species in the Southeast Asian island of Borneo. Findings of the study were published Monday in the journal ZooKeys. Scientists led by evolutionary biologist Menno Schilthuizen of the Naturalis Biodiversity Center have been studying Malaysia’s mollusks for more than two decades. The latest round of discoveries also included ten new species of “micro-jewel” mollusks from the genus Plectostoma.
Since the tiny snails cover little ground, they evolve in a unique way to adapt for small patches of habitat. However, it also makes them ecologically vulnerable. Schilthuizen pointed out that a blazing fire at Loloposon Cave could easily wipe out the Diplommatina tylocheilos population.
Why the snail evolved to become smaller and smaller
Menno Schilthuizen said that A. nana has evolved to become smaller and smaller to access microscale environments that its competitors can’t utilize. For such a tiny snail, a niche environment that differs in physical and chemical aspects means they can squeeze into small food-containing crevices that others can’t get into.
However, researchers said they wouldn’t know other details of the species without further research. They concluded the existence of A. nana by examining its discarded shells. The methods they used to collect were aimed at empty shells, said Schilthuizen. Researchers have never seen Acmella nana alive. They could make some assumptions about its behavior and diet by studying its nearest relatives. Live Acmella snails are often found in limestone caves and underground crevices, where they feed on microbial films.