A tiny snail shell with a diameter of 0.028 inches (0.7 mm) was found on the Malaysian portion of the island of Borneo by a group of scientists from the Netherlands along with another 47 new snail species of greatly varying sizes.
Acmella nana, a new species in the genus Acmella, the world’s tiniest snail. Image credit: Vermeulen JJ et al.
Some of the 48 species described by Dr Jaap Vermeulen and his colleagues from the Naturalis Biodiversity Center in Leiden are widespread in Borneo and had been familiar to scientists for decades. Yet, they had not got round to naming them until now.
One of them is the world’s smallest snail, named Acmella nana (nanus means ‘dwarf’ in Latin).
The species has a shell of merely 0.020 – 0.024 inches (0.5 – 0.6 mm) width and 0.024 – 0.031 inches (0.6 – 0.79) mm height.
The previous holder of the title, Angustopila dominikae from the Chinese province of Guangxi, discovered earlier this year, measured just 0.032 and 0.035 inches (0.80 and 0.89 mm) respectively.
Some of the new species are very rare. There are seven new species that can only be found on the 13,435 foot (4,095 m) high Mount Kinabalu.
Another example, Diplommatina tylocheilos, only lives at the entrance of the hardly accessible Loloposon Cave in Mount Trusmadi.
“The new information tells us more about isolated, or endemic, species such as the new record-holder,” Dr Vermeulen and co-authors said.
“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. This makes them excellent examples of how endemic species can arise.”
“On the other hand, their restricted distribution makes them key targets for biodiversity conservation.”
“A blazing forest fire at Loloposon Cave could wipe out the entire population of Diplommatina tylocheilos,” added team member Dr Menno Schilthuizen.
Research describing Acmella nana and other new snail species is published online in the open-access journal ZooKeys.
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Vermeulen JJ et al. 2015. Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species. ZooKeys 531: 1-139; doi: 10.3897/zookeys.531.6097
