Tag: Gastropoda

Tiny, record-breaking Chinese land snails fit almost 10 times into the eye of a needle

Minuscule snails defy current knowledge and scientific terminology about terrestrial “microsnails”. While examining soil samples collected from the base of limestone rocks in Guangxi Province, Southern China, scientists Barna Páll-Gergely and Takahiro Asami from Shinshu University, Adrienne Jochum, University and Natural History Museum of Bern, and András Hunyadi, found several minute empty light grey shells, which measured an astounding height of less than 1 mm.

The single known shell of Angustopila dominikae, named after the wife of the first author, was measured a mere 0.86 mm in shell height. Thus, it is considered to be perhaps the World’s smallest land snail species when focusing on the largest diameter of the shell. With very few reported instances of species demonstrating this degree of tininess, the team have described a total of seven new land snail species in their paper, published in the open access journal ZooKeys.

Another of the herein described new species, called Angustopila subelevata, measured 0.83-0.91 mm (mean = 0.87 mm) in height.

Two of the authors have previously described other species of tiny land snails from China and Korea in the same journal.

In their present paper, Dr. Pall-Gergely and his team also discuss the challenges faced by scientists surveying small molluscs, since finding living specimens is still very difficult. Thus, the evolutionary relationships between these species, as well as the number of existing species are yet little known.

“Extremes in body size of organisms not only attract attention from the public, but also incite interest regarding their adaptation to their environment,” remind the researchers. “Investigating tiny-shelled land snails is important for assessing biodiversity and natural history as well as for establishing the foundation for studying the evolution of dwarfism in invertebrate animals.”

“We hope that these results provide the taxonomic groundwork for future studies concerning the evolution of dwarfism in invertebrates,” they finished up.

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Original source:

Páll-Gergely B, Hunyadi A, Jochum A, Asami T (2015) Seven new hypselostomatid species from China, including some of the world’s smallest land snails (Gastropoda, Pulmonata, Orthurethra). ZooKeys 523: 31-62. doi: 10.3897/zookeys.523.6114

Cave snail from South Korea suggests ancient subterranean diversity across Eurasia

As tiny as 1.7 mm, a snail whose relatives live exclusively in the deep recesses of caves, provided a sensational discovery from the depths of Nodong cave, South Korea, back in 2000 for its collector, J. S. Lee. It is the only cave-dwelling representative of the family of hollow-shelled snails in the whole of Asia with its closest relatives known from as far as Croatia and Northern Spain. The scientists, Adrienne Jochum, Bern University and Natural History Museum Bern, Larisa Prozorova and Mariana Sharyiool from the Far Eastern Russian Academy of Sciences and Barna Páll-Gergely from Shinshu University, published its description in the open-access journalZooKeys.

The Asian species has awaited 15 years to come out of the dark for a name and into the limelight of subterranean biodiversity and conservation awareness. This barely visible snail suggests a former pan-Eurasian distribution of cave-dwelling, hollow-spired snails.

The tiny-shelled treasure, called Koreozospeum nodongense, belongs to a larger group of ancient cosmopolitan air-breathing relatives known to have been amongst the first snail colonisers of land via mangroves about 65 million years ago. Similar to its European relatives from the genus Zospeum, the South Korean snail was also found on muddy cave walls.

Although more than 1,000 caves have been explored in South Korea, Nodong is so far the only one to harbour these beautiful denizens of the dark. Hypotheses made by Culver et. al. in 2006 about the existence of a very narrow, mid-latitudinal ridge of subterranean biodiversity (ca. 42-46°N in Europe and 33-35°N in North America) might clarify this unique find.

A high amount of caves known to exist within these latitudes provide ample habitats for colonisation of life. If this hypothetical ridge were to be extended further East away from Europe, then Koreozopseum‘s gliding along walls in a South Korean cave (33-35°N) makes a strong call for further investigations and discovery of rare biodiversity.

Jochum and her international team described K. nodongense using computer tomographic scans (Nano-CT) in a video film to view and compare the contours and architecture of the very fragile shell. Chemical trace elements, such as aluminum (Al) and silicon (Si) were detected in other scans of the thin diaphanous shell using mineralogical analysis techniques (SEM-EDX). These elements may play a role in the biomineralization (hardness) of the shell or may be contaminants absorbed by the snail from sediment consisting of volcanic ash from former eruptions in the region.

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Original Source:

Jochum A, Prozorova L, Sharyi-ool M, Páll-Gergely B (2015) A new member of troglobitic Carychiidae, Koreozospeum nodongense gen. et sp. n. (Gastropoda, Eupulmonata, Ellobioidea) is described from Korea. ZooKeys 517: 39-57. doi: 10.3897/zookeys.517.10154

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Additional information:

The Naturhistorisches Museum der Burgergemeinde Bern, Switzerland and the Far Eastern Branch of the Russian Academy of Sciences supported this work.