Tag: snail

Novak Djokovic now has a tiny new snail species named after him

Do freshwater snails make good tennis players? One of them certainly has the name for it.

Enter Travunijana djokovici, a new species of aquatic snail named after famous Serbian tennis player Novak Djokovic.

Photo of Tavunijana djokovici, a new snail species from Montenegro named after Serbian tennis player Novak Djokovic. Photo by J. Grego

Slovak biospeleologist Jozef Grego and Montenegrin zoologist Vladimir Pešić of the University of Montenegro discovered the new snail in a karstic spring near Podgorica, the capital of Montenegro, during a field trip in April 2019. Their scientific article, published in the open-access, peer-reviewed journal Subterranean Biology, says they named it after Djokovic “to acknowledge his inspiring enthusiasm and energy.”

“To discover some of the world’s rarest animals that inhabit the unique underground habitats of the Dinaric karst, to reach inaccessible cave and spring habitats and for the restless work during processing of the collected material, you need Novak’s energy and enthusiasm,” the researchers explain.

T. djokovici has a milky-white shell in the shape of an elongated cone and is adapted to live in the underground habitats of the Dinaric karst. It is part of Hydrobiidae, a very diverse family of small to tiny snails – also known as mud snails – inhabiting fresh or brackish water, including caves and subterranean habitats.

The type locality where Tavunijana djokovici was found.

This is the first member of the genus Travunijana so far to be discovered in the Skadar Lake basin, and the only one found outside of the Trebišnjica river basin in Herzegovina, which points to the enigmatic distributional range of these snails across the Dinaric underground habitats. Where they came from, and how, remains a mystery.

Because of its small area of occupancy, T. djokovici is assessed as Vulnerable, according to the IUCN Red List of Threatened Species. Subterranean ecosystems, the authors of the new species emphasise, are extremely vulnerable to human-driven environmental changes, and, being obscure, they’re often overlooked during conservation efforts.

Original source:

Grego J, Pešić V (2021) First record of stygobiotic gastropod genus Travunijana Grego & Glöer, 2019 (Mollusca, Hydrobiidae) from Montenegro. Subterranean Biology 38: 65–76. https://doi.org/10.3897/subtbiol.38.64762

Huge organs defy austerity for tiny cave snails in the subterranean realm

While most of the knowledge about tiny snails comes from studying empty shells sifted out from piles of dust and sand, the present research is the first contemporary microscopic exploration of organs in cave snails tinier than 2 mm. The paper, published in the open-access journal Subterranean Biology, reveals that underneath the seemingly fragile shells of the Zospeum genus, there are strikingly huge organs.

A number of remarkable observations such as an enormous kidney, grooved three-pointed teeth and a huge seasonally present penis are reported in the recent study, conducted by Adrienne Jochum, Naturhistorisches Museum der Burgergemeinde Bern, Switzerland, and her international team of researchers from University of Bern, Switzerland; Shinshu University, Japan; Universitaetsklinikum Giessen und Marburg GmbH, Germany; Justus-Liebig University Giessen, Germany; University of Ljubljana, Slovenia; University of Bern Goethe-University Frankfurt, Germany; Ruhr University Bochum, Germany; Croatian Biospeleological Society, Croatia and University Duisburg-Essen, Germany.

The scientists describe these characteristics as adaptations the miniature creatures have acquired in order to survive austerity in the subterranean realm.

Usually, adaptations to cave life can include blindness or lack of eyes, loss of pigmentation, sensitivity to changes in temperature and humidity, a high starvation tolerance, or anatomical compromises such as small size and transparent shells. The present study shows that miniscule carychiid subterranean snails have developed huge organs to tolerate the unique conditions of cave life.

“Studying adaptations in extreme environments such as those found in snails of subterranean habitats can help us to understand mechanisms driving evolution in these unique habitats,” explains the first author.

Glassy cave-dwelling snails known only from Northern Spain, the southern Eastern Alpine Arc and the Dinarides might have tiny hearts, but their enormous kidney extends from one to two thirds of the total length of their minute shells. This phenomenon could be explained as an effective mechanism used to flush out large amounts of excess water during flooding seasons in caves.

The same impressive creatures have also developed elaborate muscular plates, forming the girdle that surrounds the gastric mill (gizzard) in their digestive tract. The muscular gizzard grinds the grainy stew of microorganisms and fungi the snails find in moist cave mud. These mysterious creatures graze stealthily using an elastic ribbon (radula), aligned with seemingly endless rows of three-pointed, centrally-grooved teeth, as they glide through the depths of karst caves while searching for food and partners.

Deprived from the hospitable aspects of life we have grown used to, some of the snails discussed in the present paper have evolved their reproductive system in order to be able to reproduce in the harshest of environments, even when they fail to find a partner for an extended period of time.

As a result, not only are these snails protandric hermaphrodites, meaning that they possess male sexual features initially, which later disappear so that the female phase is present, but they have a large retractable, pinecone-shaped penis for instantaneous mating in the summer when mating is most probable. To guarantee offspring, a round sac, known as the receptaculum seminis, stocks sperm received from a partner during a previous mating and allows them to self-inseminate if necessary.

Teeth in these cave snails are also described using histology for the first time. They bear a median groove on the characteristic cusps known for the Carychiidae.

Sketchy, past dissections provide the current knowledge upon which the findings from this investigation are based. Otherwise, historical descriptions of these tiny snails are only known from empty shells found in samples of cave sediment. The genus Zospeum can only be found alive by inspecting cave walls using a magnifying glass.

“Knowledge of their subterranean ecology as well as a “gut feeling” of where they might be gliding about in their glassy shells is necessary to find them,” comments Adrienne Jochum. The authors also emphasize that this groundbreaking work is important for biodiversity studies, for biogeographical investigations and for conservation management strategies.

Adrienne Jochum and her team investigated the insides of the shells using nanoCT to differentiate species in synchronization with molecular approaches for genetic delimitation. Four well-defined genetic lineages were determined from a total of sixteen Zospeumspecimens found in the type locality region of the most common representative, Zospeum isselianum. This investigation is the first integrative study of live-collected Zospeum cave snails using multiple lines of data (molecular analyses, scanning electron microscopy (SEM), nano-computer tomography (nanoCT), and histology.

This work is dedicated to the industrious Slovenian malacologist Joze Bole, whose work greatly inspired the present research.

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Original source:

Jochum A, Slapnik R, Klussmann-Kolb A, Páll-Gergely B, Kampschulte M, Martels G, Vrabec M, Nesselhauf C, Weigand AM (2015) Groping through the black box of variability: An integrative taxonomic and nomenclatural re-evaluation of Zospeum isselianum Pollonera, 1887 and allied species using new imaging technology (Nano-CT, SEM), conchological, histological and molecular data (Ellobioidea, Carychiidae). Subterranean Biology 16: 123-165. doi: 10.3897/subtbiol.16.5758

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

Additional information:

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

Brushing off the dust: New snail species found lying in a museum since the 19th century

Having been collected back in the 19th century during an expedition in South America, a rather small snail species has been sitting around on the shelves of Madrid’s National Museum of Natural Sciences ever since. Covered in more than a century-old dust, it was described as new only recently when an obscure specimen placed in the long tail of a historical collection drew the attention of Drs. Breure and Araujo. Their research is now published in the open-access journal ZooKeys.

The small snail species, called P. cecepeus, had been staying ‘undercover’ for more than a century and a half among the numerous specimens, that formed a total of 20 new species when they were gathered during the historical ‘Comisión Científica del Pacífico’ expedition in South America. With the average undescribed museum invertebrate’s ‘shelf life’ being 20.7 years, it comes as no surprise that the herein described mollusc attracted the attention of the scientists.

Other than its moderately small size, the new species has been characterised with an irregular shape and narrow reddish-brown streaks running vertically across the shell. The surface is rather glossy and coloured in light chestnut-brown.

Although it has been accepted that the snail was found in Ecuador, the authors argue that the locality is “unfortunately very imprecise,” given the data supplied by the collectors. Therefore, the researchers suggest that additional field work should be done in the area so that the “true home” of their discovery is finally recorded.

“Although description of new species that have remained unnoticed for more than a century remains a rare event, it highlights the need for revisions of museum collections and especially the historical parts of these,” conclude the researchers.

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Original source:

Breure ASH, Araujo R (2015) A snail in the long tail: a new Plekocheilus species collected by the ‘Comisión Científica del Pacífico’ (Mollusca, Gastropoda, Amphibulimidae). ZooKeys 516: 85-93. doi: 10.3897/zookeys.516.10228