Agents of food-borne zoonoses confirmed to parasitise newly-recorded in Thailand snails

Parasitic flatworms known as agents of food-borne zoonoses were confirmed to use several species of thiarid snails, commonly found in freshwater and brackish environments in southeast Asia, as their first intermediate host. These parasites can cause severe ocular infections in humans who consume raw or improperly cooked fish that have fed on infected snails.

Parasitic flatworms known as agents of food-borne zoonoses were confirmed to use several species of thiarid snails, commonly found in freshwater and brackish environments in southeast Asia, as their first intermediate host. These parasites can cause severe ocular infections in humans who consume raw or improperly cooked fish that have fed on infected snails. The study, conducted in South Thailand by Thai and German researchers and led by Kitja Apiraksena, Silpakorn University, is published in the peer-reviewed open-access journal Zoosystematics and Evolution.

“Trematode infections are major public health problems affecting humans in southeast Asia. Trematode infections depend not only on the habit of people, but also on the presence of first and second intermediate host species, resulting in the endemic spread of parasites, such as intestinal and liver flukes in Thailand”.

explain the scientists.

The snails of concern belong to the genus Stenomelania, have elongated and pointed shells and can be found near and in the brackish water environment of estuaries in the Oriental Region, from India to the Western Pacific islands. Worryingly enough, science does not know much else about these snails to date. Further, these species are hard to distinguish from related trumpet snails, because of the similarities in their shell morphology.

In order to provide some basic knowledge about the parasitic worms in Thailand and neighbouring countries, the research team collected a total of 1,551 Stenomelania snails, identified as four species, from streams and rivers near the coastline of the south of Thailand in Krabi, Trang and Satun Provinces. Of them, ten were infected with trematodes. The parasites were found at seven of the studied localities and belonged to three different species. In Krabi Province, the researchers observed all three species.

Speculating on their presence, the scientists suspect that it could be related to the circulation of sea currents, as the flow of water along the Andaman coast is affected by the monsoon season.

In conclusion, the researchers note that it is a matter of public health that further research looks into the biodiversity and biology of these snails, in order to improve our knowledge about the susceptibility of Stenomelania snails to food-borne zoonotic.

“This finding indicated that the resulting parasitic diseases are still largely neglected in tropical medicine, so further studies should be performed on the prevalence of various trematode-borne diseases in locations with snail occurrences in Thailand,”

they say.

Research article:

Apiraksena K, Namchote S, Komsuwan J, Dechraksa W, Tharapoom K, Veeravechsukij N, Glaubrecht M, Krailas D (2020) Survey of Stenomelania Fisher, 1885 (Cerithioidea, Thiaridae): The potential of trematode infections in a newly-recorded snail genus at the coast of Andaman Sea, South Thailand. Zoosystematics and Evolution 96(2): 807-819. https://doi.org/10.3897/zse.96.59448

Tiny cave snail with muffin-top waistline rolls out of the dark in Laos

A new species of tiny cave snail that glistens in the light and has a muffin-top-like bulge, was discovered by Marina Ferrand of the French Club Etude et Exploration des Gouffres et Carrières (EEGC), during the Phouhin Namno caving expedition in Tham Houey Yè cave in Laos in March 2019. The new species, named Laoennea renouardi was described in the open-access, peer-reviewed journal Subterranean Biology.

Tham Houey Yè cave (Vientiane Province, Laos), inhabited by the newly discovered “muffin-topped” snail species Laoennea renouardi.
Photo by Jean-Francois Fabriol.

A new species of tiny cave snail that glistens in the light and has a muffin-top-like bulge, was discovered by Marina Ferrand of the French Club Etude et Exploration des Gouffres et Carrières (EEGC), during the Phouhin Namno caving expedition in Tham Houey Yè cave in Laos in March 2019. The new species, Laoennea renouardi, is 1.80 mm tall and is named after the French caver, Louis Renouard, who explored and mapped the only two caves in Laos known to harbor this group of tiny snails. Only two species of Laoennea snail are known so far, L. carychioides and now, L. renouardi

Caver and scientist, Dr. Adrienne Jochum, affiliated with the Natural History Museum Bern and University of Bern (Switzerland), as well as the Senckenberg Research Institute and Natural History Museum (Frankfurt, Germany) described the new species and its cave habitat together with co-authors: Estée Bochud, Natural History Museum Bern; Quentin Wackenheim, Laboratoire de Géographie Physique (Meudon, France) and Laboratoire Trajectoires (Nanterre, France); Marina Ferrand, EEGC; and Dr. Adrien Favre, Senckenberg Research Institute and Natural History Museum, in the open-access, peer-reviewed journal Subterranean Biology.

The new transparent “muffin-topped” snail, Laoennea renouardi.
Photo by Estée Bochud.

“The discovery and description of biodiversity before it disappears is a major priority for biologists worldwide. The caves in Laos are still largely underexplored and the snails known from them remain few in number,”

points out Dr. Jochum. 

The fact that two species of tiny cave snails of the same group were found in two caves located in two independent karstic networks 3.4 km apart, caused the authors to question evolutionary processes in these underground hotspots of biodiversity. The authors hypothesise that the two caves might have been connected during the Quaternary, around 100–200 thousand years ago. In time, the river Yè might have formed a barrier, thus disconnecting the cave systems and separating the populations. As a result, the snails evolved into two different species.

A new species of tiny cave snail that glistens in the light and has a muffin-top-like bulge, was discovered by Marina Ferrand of the French Club Etude et Exploration des Gouffres et Carrie?res (EEGC), during the Phouhin Namno caving expedition in Tham Houey Yè cave in Laos in March 2019. The new species, Laoennea renouardi, is 1.80 mm tall and is named after the French caver, Louis Renouard, who explored and mapped the only two caves in Laos known to harbor this group of tiny snails. Only two species of Laoennea snail are known so far, L. carychioides and now, L. renouardi.

Caver and scientist, Dr. Adrienne Jochum, affiliated with the Natural History Museum BernUniversity of Bern (Switzerland), as well as the Senckenberg Research Institute and Natural History Museum (Frankfurt, Germany) described the new species and its cave habitat together with co-authors: Estée Bochud, Natural History Museum Bern; Quentin Wackenheim, Laboratoire de Géographie Physique (Meudon, France) and Laboratoire Trajectoires (Nanterre, France); Marina Ferrand, EEGC; and Dr. Adrien Favre, Senckenberg Research Institute and Natural History Museum, in the open-access, peer-reviewed journal Subterranean Biology.

Map of the two caves on opposite sides of the River Yè, Vientiane Province, Laos.
Image by Louis Renouard.

The fact that two species of tiny cave snails of the same group were found in two caves located in two independent karstic networks 3.4 km apart, caused the authors to question evolutionary processes in these underground hotspots of biodiversity. The authors hypothesise that the two caves might have been connected during the Quaternary, around 100-200 thousand years ago. In time, the river Yè might have formed a barrier, thus disconnecting the cave systems and separating the populations. As a result, the snails evolved into two different species.

***

Original Source:

Jochum A, Bochud E, Favre A, Ferrand M, Wackenheim Q (2020) A new species of Laoennea microsnail (Stylommatophora, Diapheridae) from a cave in Laos. Subterranean Biology 36: 1-9.
https://doi.org/10.3897/subtbiol.36.58977

Citizen scientists discover a new snail and name it after Greta Thunberg

A new to science species of land snail was discovered by a group of citizen scientists working together with scientists from Taxon Expeditions, a company that organises scientific field trips for teams consisting of both scientists and laypeople. Having conducted a vote on how to name the species, the expedition participants and the local staff of the National Park together decided to name the mollusc Craspedotropis gretathunbergae. The species name honors the young Swedish activist Greta Thunberg for her efforts to raise awareness about climate change. The study is published in the open-access journal Biodiversity Data Journal.

“The newly described snail belongs to the so-called caenogastropods, a group of land snails known to be sensitive to drought, temperature extremes and forest degradation”,

says snail expert and co-founder of Taxon Expeditions, Dr. Menno Schilthuizen.

All individuals were found very close to the research field station (Kuala Belalong Field Studies Centre) at the foot of a steep hill-slope, next to a river bank, while foraging at night on the green leaves of understorey plants.

Citizen scientist J.P. Lim, who found the first specimen of Greta Thunberg’s snail says:

“Naming this snail after Greta Thunberg is our way of acknowledging that her generation will be responsible for fixing problems that they did not create. And it’s a promise that people from all generations will join her to help”.


Taxon Expeditions participant J.P. Lim collecting snails.
Credit: Taxon Expeditions – Pierre Escoubas
License: CC-BY 4.0

The expedition team approached Ms. Thunberg who said that she would be “delighted” to have this species named after her. 

Video about Taxon Expeditions & Greta Thunberg snail
Credit: Taxon Expeditions

However, this is not the first time that Taxon Expeditions team names a species in honour of an environmental advocate. In 2018, they named a new species of beetle after famous actor and climate activist Leonardo DiCaprio. Mr. DiCaprio temporarily changed his profile photo on Facebook to the photo of “his” beetle to acknowledge this honour.


View of the Ulu Temburong National Park in Brunei from the canopy bridge.
Credit: Taxon Expeditions – Pierre Escoubas
License: CC-BY 4.0

Original source:

Schilthuizen M, Lim JP, van Peursen ADP, Alfano M, Jenging AB, Cicuzza D, Escoubas A, Escoubas P, Grafe U, Ja J, Koomen P, Krotoski A, Lavezzari D, Lim L, Maarschall R, Slik F, Steele D, Ting Teck Wah D, van Zeeland I, Njunjić I (2020) Craspedotropis gretathunbergae, a new species of Cyclophoridae (Gastropoda: Caenogastropoda), discovered and described on a field course to Kuala Belalong rainforest, Brunei. Biodiversity Data Journal 8: e47484. https://doi.org/10.3897/BDJ.8.e47484

Tiny thorn snail discovered in Panama’s backyard

Close-up view of live individuals of the new species crawling on a leaf.

Discoveries of biodiversity at the Lilliputian scale are more tedious than it is for larger animals like elephants, for example. Furthermore, an analysis producing a DNA barcode – a taxonomic method using a short snippet of an organism’s DNA – is not enough to adequately identify it to the species level.

In the case of tiny thorn snails – appearing as minute white flecks grazing in moist, decomposing leaf litter – it is the shell that provides additional and reliable information needed to verify or question molecular assessment of these otherwise, nondescript critters.

Broadleaf forest litter with white arrows indicating the newly described species on the leaves.

However, at 2 mm, thorn snails are too small and fragile to handle and the few, if any, tangible details on the outside of the shells can only be seen using a high-powered microscope and computed tomographic (CT) images.

This is exactly how the interdisciplinary team of Dr Adrienne Jochum, Naturhistorisches Museum der Burgergemeinde Bern (NMBE) and University of Bern, Dr. Bernhard Ruthensteiner, Zoologische Staatssammlung Muenchen, Germany, Dr. Marian Kampschulte, University Hospital of Giessen and Marburg, Gunhild Martels, Justus-Liebig University Giessen, Jeannette Kneubühler, NMBE and University of Bern, and Dr. Adrien Favre, Senckenberg Research Institute and Natural History Museum Frankfurt, managed to clarify the identity of a new Panamanian species. Their study is published in the open-access journal ZooKeys.

Even though the molecular analysis flagged what it was later to be named as the new to science species, Carychium panamaense, the examination left no shell for the description of the new snail to be completed, let alone to serve as tangible, voucher material in a museum collection available to future researchers. The mini forest compost-grazer had to wait for another five years and Dr. A. Favre, who collected fresh material while traveling in Panama.

The new snail is currently the second member of the family Carychiidae to be discovered in Panama. The first Panamanian, and southern-most member of its kind in the Western Hemisphere, is C. zarzaae, which was also described by Dr. A. Jochum and her team along with two sister species from North and Central America. The study was published in ZooKeys last year.

Much like X-rays showing the degree of damage in a broken bone, CT images visualise the degree of sinuosity of the potato chip-like wedge (lamella) along the spindle-like mast (columella) inside the thorn snail’s shell. These structures provide stability and surface area on which the snail exerts muscular traction while manoeuvring the unwieldy and pointed, signature thorn-like shell into tight nooks and crannies. The alignment and degree of waviness of the lamella on the columella is also used by malacologists (mollusc specialists) to differentiate the species.

These are computed tomographic (CT) images of the new thorn snail species.

Normally, a study of a thorn snail’s shell would require drilling out minute ‘windows’ in the shell by using a fine needle under a high microscope magnification.

“This miserable method requires much patience and dexterity and all too often, the shell springs open into oblivion or disintegrates into dust under pressure,” explains Dr. A. Jochum. “By exposing the delicate lamella using non-manipulative CT imaging, valuable shell material is conserved and unknown diversity in thorn snails becomes widely accessible for further study and subsequent conservation measures.”

The authors are hopeful that C. panamaense and C. zarzaae, which both inhabit the La Amistad International Park, Chiriquí, will remain a conservation priority along with other animalian treasures including the Resplendent Quetzal, Three-Wattled Bellbird and the Crested Eagles.

The park is considered the 1st bi-national biosphere reserve, as it occupies land in both Costa Rica and Panama, and constitutes a UNESCO World Heritage Site since 1990.

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Original Source:

Jochum A, Ruthensteiner B, Kampschulte M, Martels G, Kneubühler J, Favre A (2018) Fulfilling the taxonomic consequence after DNA Barcoding: Carychium panamaense sp. n. (Eupulmonata, Ellobioidea, Carychiidae) from Panama is described using computed tomographic (CT) imaging. ZooKeys 795: 1-12. https://doi.org/10.3897/zookeys.795.29339

New ‘scaly’ snails species group following striking discoveries from Malaysian Borneo

Six new species of unique land snails whose shells are covered with what look like scales have been described from the biodiversity hotspot of Malaysian Borneo by scientists Mohd Zacaery Khalik, Universiti Malaysia Sarawak, Kasper Hendriks, University of Groningen, Jaap Vermeulen, JK Art & Science, and Prof Menno Schilthuizen, Naturalis Biodiversity Center. Their paper is published in the open access journal ZooKeys.

Thanks to their conspicuous structures, the mollusks have been added to a brand new species group of land snails to be commonly known as the ‘scaly’ snails, so that they can be set apart from the rest in the genus Georissa. Why it is that only some of the species in the genus sport the unique ‘scales’, remains unknown.

Fascinated with the minute ‘scaly’ snail fauna of Borneo, the researchers carried out fieldwork between 2015 and 2017 to find out how these curious shells evolved. In addition, they also examined material deposited in museum and private snail collections.

Apart from DNA data, which is nowadays commonly used in species identification, the team turned to yet-to-become-popular modern tools such as 3D modelling, conducted through X-ray scanning. By doing so, the researchers managed to look at both the inner and outer surfaces of the shells of the tiny specimens from every angle and position, and examine them in great detail.

The researchers note that to identify the ‘scaly’ snails to species level, one needs a combination of both DNA and morphological data:

“Objective species delimitation based solely on molecular data will not be successful for the ‘scaly’ snails in Georissa, at least if one wishes for the taxonomy to reflect morphology as well.”

The six new species are all named after the localities they have been originally collected from, in order to create awareness for species and habitat conservation.

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Watch rotation and cross-section of the 3D models of the studied species here.

Original source:

Khalik MZ, Hendriks K, Vermeulen JJ, Schilthuizen M (2018) A molecular and conchological dissection of the “scaly” Georissa of Malaysian Borneo (Gastropoda, Neritimorpha, Hydrocenidae). ZooKeys 773: 1-55. https://doi.org/10.3897/zookeys.773.24878

Threatened Alabama snail renamed after a case of mistaken identity

Contrary to what scientists have known for over 100 years, the Painted Rocksnail turns out to have never existed outside the Coosa River system

Alabama has some of the highest diversity of freshwater snails in the world, but many snails are at high risk of extinction.

An essential part of determining extinction risk is knowing the range of a given species and determining how much its range has contracted owing to anthropogenic impacts, but mistaken identity or misidentification can complicate conservation efforts.

Image1_PaintedRocksnailsThe Painted Rocksnail, a small snail from the Coosa River system, has been mistakenly identified as other species for over 100 years.

In a study published in the open access journal ZooKeys, scientists Dr. Nathan Whelan, U.S. Fish and Wildlife Service, Dr. Paul Johnson and Jeff Garner, Alabama Department of Conservation and Natural Resources, and Dr. Ellen Strong, Smithsonian Institution National Museum of Natural History, tackled the identity of the Painted Rocksnail, a small federally threatened species native to the Mobile River basin in Alabama.

Freshwater snails are notoriously difficult to identify, as the shells of many species can look very similar. Keeping this in mind, the researchers began to notice that many shells identified as the Painted Rocksnail in museums around the world were misidentified specimens of the Spotted Rocksnail, another snail species found in Alabama.

After examining shells at the Academy of Natural Sciences of PhiladelphiaMuseum of Comparative Zoology at Harvard, National Museum of Natural History, North Carolina Museum of Natural SciencesFlorida Museum of Natural History, and Natural History Museum in London, in addition to hundreds of hours of their own sampling throughout the Mobile River basin, the authors determined that all previous reports of the Painted Rocksnail from outside the Coosa River system were mistakes.

Despite the Painted Rocksnail dwelling in well-studied rivers near large population centers, mistaken identity of the species has persisted almost since the species was described back in 1861 by Isaac Lea.

Only after careful examination of shells collected in the last 150 years and analyses of live animals were the researchers able to confidently determine that the Painted Rocksnail never occurred outside the Coosa River system.

The study has implications for the conservation of the Painted Rocksnail, as the species was historically more restricted than previously thought. Recent surveys by the authors only found the species in small stretches of the Coosa River, Choccolocco Creek, Buxahatchee Creek, and Ohatchee Creek.

In conclusion, the authors note the importance of natural history museums and the importance of studying snails in the southeastern United States.

“Without the shells stored in natural history museums we would have never been able to determine that the supposed historical range of the Painted Rocksnail was incorrect, which could have resulted in less effective conservation efforts for an animal that is very important to the health of rivers in Alabama,” they say.

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Original Source:

Whelan NV, Johnson PD, Garner JT, Strong EE (2017) On the identity of Leptoxis taeniata – a misapplied name for the threatened Painted Rocksnail (Cerithioidea, Pleuroceridae). ZooKeys697: 21-36. https://doi.org/10.3897/zookeys.697.14060

Three new mini thorn snails described from Georgia (USA), Belize and Panama

Although computer tomography (CT) is widely used in medicine, its application in micro snail identification is still at the pioneering stage.

However, Dr Adrienne Jochum from the Naturhistorisches Museum der Burgergemeinde Bern (NMBE), Switzerland and her interdisciplinary team of German and Swiss scientists (Dr. Alexander M. Weigand, University of Duisburg-Essen, Estee Bochud and Thomas Inäbnit, NMBE and the University of Bern, Dorian D. Dörge, Goethe University, Frankfurt, Dr. Bernhard Ruthensteiner, Zoologische Staatssammlung Muenchen, Dr. Adrien Favre, Leipzig University, Gunhild Martels and Dr. Marian Kampschulte, Justus-Liebig University Giessen) have recently applied it in their research, now published in the journal ZooKeys.

CT SCAN C. hardieiAs a result of their revolutionary approach, the scientists report three new thorn snail species – tiny, colourless and highly fragile creatures that measure less than 2 mm and belong to the genus Carychium.

Much like X-rays showing the degree of damage in broken bones, CT scans provide access to snail shells. Differences, such as the degree of sinuosity of the potato chip-like wedge (lamella), elegantly gliding along the spindle-like columella, become visible. These structures provide stability and surface area to exert muscular traction while manoeuvring the unwieldy shell into tight cavities. The alignment and degree of undulation of the lamella on the columella is also used by malacologists (mollusc specialists) to identify different thorn snail species.

Conventionally, examination of this signatory character requires cutting a hole in the shell with a fine needle under the microscope. This tedious method requires a much patience and dexterity and, all too often, the shell cracks open or disintegrates into dust under pressure. By exposing the delicate lamella to non-manipulative CT scans, Dr. Jochum and her team have found the best method to differentiate not only thorn snails but also many other micro creatures.

Together with G. Martels and Dr. M. Kampschulte, Dr. Jochum described new micro snails for the first time using CT in East Asian hypselostomatid snails in 2014. The first subterranean Asian relative of the thorn snails (Koreozospeum nodongense), was also described by Dr. Jochum thanks to CT scans in 2015.

The scientists studied and compared thorn snails collected from Mexico, Florida (USA) and Costa Rica.

Curiously, the new species Carychium hardiei was discovered by accident by Dr. Jochum en route to the Atlanta Airport during a rest stop in Georgia (USA). The snail is named after the American naturalist and field biologist Frank Hardie. Another species, Carychium belizeense, was found in the Bladen Nature Reserve in Belize and is named after its country of origin. The third, Carychium zarzaae from Panama, is named after Eugenia Zarza, collector of material for this study, including this species.

In total, there are fourteen species of thorn snails known in North and Central America. Their distribution ranges from as far north as northern Ontario, Canada through North America (including Bermuda and Jamaica) and south through Central America to Costa Rica. Thorn snails also live as far north as northern Sweden and as far south as sub-equatorial Java. Worldwide, this genus spans the Nearctic, Palearctic and Indomalayan biogeographic realms.

Thorn snails live in tropical and temperate forests, meadows and riparian zones, where they comprise the decomposer community in leaf litter of ecologically stable environments.

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Original Source:

Jochum A, Weigand AM, Bochud E, Inäbnit T, Dörge DD, Ruthensteiner B, Favre A, Martels G, Kampschulte M (2017) Three new species of Carychium O.F. Müller, 1773 from the Southeastern USA, Belize and Panama are described using computer tomography (CT) (Eupulmonata, Ellobioidea, Carychiidae). ZooKeys 675: 97-127. https://doi.org/10.3897/zookeys.675.12453

Species new to science named after a ‘Dungeons & Dragons’ character

Focused on terrestrial gastropods, more commonly known as land snails, a joint team of biologists from the Natural History Museum of Stuttgart, Germany and the Zoology Museum of São Paulo, Brazil, have been researching the Brazilian caves. In their latest paper, published in the journal Zoosystematics and Evolution, the scientists describe the fauna from several caves in central Brazil, including a new tiny species named after a character from the popular fantasy tabletop role-playing game Dungeons & Dragons.

The team of Dr. Rodrigo Salvador, Daniel Cavallari and Dr. Luiz Simone encountered a rich assembly of species, several of which measured as much as a few millimetres. However, apart from filling important gaps in the knowledge of these tropical animals, they went even further, having discovered a land snail new to science. While it is not uncommon for studies dealing with the invertebrate fauna to end up describing new species, this minute mollusc (nearly 2 mm in length) attracted extra attention. The team which discovered the mollusc has named it Gastrocopta sharae, after Shar, the goddess of darkness, caverns and secrets in Dungeons & Dragons.

“It’s a fitting name for a tiny snail that lives hidden in the dark recesses of a cavern,” explain the authors. “If your knowledge of mythological beings seems to have failed you, do not fret. Usually biologists tend to honour Greek and Roman deities when naming species, but the goddess Shar has a more colourful background. She is from Dungeons & Dragons, the most famous role-playing game in the world, currently in its 5th edition and a staple of geek culture.”

Nevertheless, this is not the first time that Dungeons & Dragons has been immortalised in a species’ scientific name. In 2014, the very same team described another tiny snail, this time, one with a taste for deep waters, specifically those of the Atlantic Ocean. The scientists named it Halystina umberlee, after another Dungeons & Dragons goddess – Umberlee, who commands the harshness and perils of the sea.

The tropical snails are still poorly understood, although they are one of the most threatened animal groups – both by human activities and environmental changes. Moreover, since cave-dwelling invertebrates, in general, receive scarce attention from researchers, it should come as no surprise that cave-dwelling snails are even less known.

“Getting to know the fauna inhabiting each cavern is a demanding task, but a much-needed one,” note the researchers. “Caverns are known to have very fragile ecosystems and several lack proper protection, so works like ours are an important step for conservation efforts.”

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Original source:

Salvador RB, Cavallari DC, Simone LRL (2017) Taxonomical study on a sample of land and freshwater snails from caves in central Brazil, with description of a new species. Zoosystematics and Evolution 93(1): 135-141. https://doi.org/10.3897/zse.93.10995

New land snail species from Australia shows dissection not necessary to identify molluscs

Dissection might prove unnecessary when identifying new molluscs after scientists Corey Whisson, Western Australian Museum, and Dr Abraham Breure, Naturalis Biodiversity Centre, the Netherlands, and Royal Belgian Institute of Natural Sciences, Belgium, described a previously unknown land snail based on its genitalia, yet without damaging the specimen in the slightest. The new species is published in the open access journal ZooKeys.

The biologists described the first new Australian land snail species of this family for the last 33 years thanks to micro-computed tomography (micro-CT) and reconstruction with specialised software. This novel method, likely applied for identification of molluscs for the first time in history, uses X-rays to create cross-sections of the genitalia, so that a 3D model can be created without damaging the specimen. This can be then compared to known related taxa’s genitalia in order to show if there are enough differences to prove species delimitation.

The scientists note Img2that despite the satisfying results, micro-CT is time-consuming and “quite laborious” approach. “However, in the case of a single or just a few specimens, this may be an alternative to destructive dissection,” says Dr Abraham Breure in his personal blog.

The new land snail, called Bothriembryon sophiarum after Dr Abraham Breure’s wife Sophie J. Breure and Corey Whisson’s first daughter Sophie Jade Whisson, can only be found along a 180-kilometre line running across the escarpment and cliff tops of the Baxter Cliffs and Hampton Ranges in Western Australia. Given its restricted distributional range, it is considered a short-range endemic.

The mollusc is characterised with a slender high-spired shell, built specifically for the demanding nature of its habitat. Dwelling in rocky limestone substrate, which is often fractured with narrow cracks and fissures, the snail has developed a slender shell, so that it can move easily through cavities and under rocks. On the other hand, being predominantly cream in colour with reddish or greyish brown blotches, it successfully blends with the limestone.

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Original source:

Whisson CS, Breure ASH (2016) A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-eastern Western Australia. ZooKeys 581: 127-140. doi:10.3897/zookeys.581.8044

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