New snail species with semi-transparent shell discovered in Lukina Jama cave system in Croatia

September 17, 2013 – In one of the 20 deepest caves in the world, and the deepest in Croatia, Lukina jama-Trojama, scientists from the Croatian Biospeleological Society have found a new snail species which has semi-transparent shell.

The newly found snail species, named Zospeum tholussum, is considered to be a true eutroglobiont or cave-dweller, writes ibtimes.com.

It is a very small snail with a translucent shell which lives in complete darkness, has no eyes and moves only a couple of millimeters or centimeters per week.

The new cave-dwelling snail, Zospeum tholussum, discovered in Croatia’s Lukina Jama–Trojama cave system.

The new cave-dwelling snail, Zospeum tholussum, discovered in Croatia’s Lukina Jama–Trojama cave system. Image credit: Jana Bedek

“They only creep a few millimeters or centimeters a week, and mainly in circles, grazing at one point where they live,” said Dr Alexander Weigand, taxonomist of the Goethe-University Frankfurt, Germany, who has described a new species in a paper published in the open-access journal Subterranean Biology.

The species was found during an expedition to explore the cave in order to determine its depth. Deep underground, fauna samples were collected, and one living specimen of this tiny and fragile snail was brought up from the depth of 980 m, along with eight of its empty shells!

“The single living specimen was found in an unnamed large chamber with lots of stones, rocks and sand. A temporal small stream of running water was present close to the collecting site. Air temperature was between 3.3 – 3.5 degrees Celsius, water temperature 5.1 degrees Celsius and air humidity 100 per cent. Shells were observed beginning from 800 m depth till the bottom of the cave. Shells were generally found on layers of mud,” Dr Weigand wrote in a published paper.

Unlike other Zospeum species which are only slightly movable, it is assumed that the new snails move by passive transport, via water or other animals, since they have been found in a muddy habitat, close to the cave’s drainage system.

The Lukina Jama–Trojama on Velebit is the deepest cave system in Croatia. Due to its microclimate, scientists are eager to explore it in search of new species so we might expect more great discoveries in the future.

Zospeum tholussum - living specimen (solid border) and empty shell (dotted border).

Zospeum tholussum – living specimen (solid border) and empty shell (dotted border). Image credit: Alexander Weigand

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Bibliographic information: Weigand AM. 2013. New Zospeum species (Gastropoda, Ellobioidea, Carychiidae) from 980 m depth in the Lukina Jama–Trojama cave system (Velebit Mts., Croatia). Subterranean Biology 11: 45 – 53; doi: 10.3897/subtbiol.11.5966

Source: http://www.pensoft.net/journals/subtbiol/article/5966/new-zospeum-species-gastropoda-ellobioidea-carychiidae-from-980-m-depth-in-the-lukina-jama%E2%80%93trojama-cave-system-velebit