New Species Of Tardigrade Found Clawing Through Sand Dunes In Finland

Move aside, sandworms. Arrakis belongs to tardigrades now.


Rachael Funnell

Social Editor and Staff Writer

clockNov 15 2022, 11:26 UTC
tardigrade sand dune
Life in the dune calls for reduced limbs and claws, apparently. Image credit: Oleh Liubimtsev /

A new species of tardigrade, everybody’s favorite extremophiles, has been discovered in sand dunes in Rokua National Park in Finland. It joins a rare elite of tardigrades that contains just four other known species and is characterized by reduced legs and claws that are adaptations for sand and soil living.

The rarely found species complex is known as Macrobiotus pseudohufelandi and this newly discovered variety brings the total count to five known species. The latest addition has been named Macrobiotus naginae.


As for its species name, it’s got a pretty badass etymology. It’s named after the character Nagini from the Harry Potter book series, Lord Voldemort’s treasured snake companion.

“Formerly a cursed woman who is ultimately and irreversibly transformed into a limbless beast, this fictional character provides a fitting name for the new species in the pseudohufelandi complex, which in turn is characterized by reduced legs and claws,” write the authors in a study on the discovery. M. naginae’s reduced claws make it well adapted to life in the dune as it can use them to claw its way between grains of sand.

Though there be no sandworm to engulf the tardigrades, there are Arianta arbustorum snails. Curiously, in a second study, the researchers were able to retrieve living tardigrades from the feces of a quarter of the snails they found, providing the first direct evidence that they can tolerate journeying through the snails’ digestive systems.


Like Andy Dufresne, “who crawled through a river of sh!t and came out clean on the other side”, a third of tardigrade specimens found in the feces proved to have survived the journey being defecated alive (a skill shared by some beetles who can fight their way out of the anuses of frogs). Some of those recovered from the snail poop even went on to reproduce, proving once again that it takes an awful lot to kill a tardigrade.

As for why this might be helpful, it seems riding through the digestive system of a snail can be a bit like hitchhiking on the highway. Tardigrades tended to re-emerge at the other end of the snails about two days after being ingested, which in the wild would translate to quite a distance. It’s possible, then, that adapting to survive the undignified carpool is a way of helping the species to disperse across distances and overcome dry patches that might halt their movement when riding solo.

“This two-day delay could result in dispersal distances of about 10 meters [33 feet],” reads a statement on the finding. “This is a considerable distance for organism under 1 millimeter [0.04 inches], for which just few millimeters of dry area would thwart its movement.”


“Moreover, snails and tardigrades share the same moss-rich and humid habitats; therefore, the destination of this 'snail-ride' is likely suitable for the surviving tardigrades.”

The studies are published in the journals Zoological Studies and Ecology.

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