Tag: mollusks

Citizen scientists discover new ‘snug’ in Brunei forest, name it after retiring field centre manager

Working with the scientific travel agency Taxon Expeditions, citizen scientists studed specimens, and analyse their DNA in a field camp in the heart of the forest.

Semislugs, or ‘snugs’ as they are affectionately known among mollusc researchers, are like the squatters of the snail world: they do carry a home on their back but it is too small to live in. Still, it offers a sort of protection, while not getting in the way of the worm-like physique of the slug. For reasons unknown, on the island of Borneo, which is shared among the countries of Brunei, Malaysia, and Indonesia, most slugs are of the semislug type. The genus Microparmarion there consists of around 10 semislug species, most of which are found in the cooler forests of the mountains. So, when citizen scientists discovered a Microparmarion in the hot lowland forest of Ulu Temburong National Park, Brunei, as part of their expedition, they were surprised.

A team of citizen scientists in the Brunei forest, searching for slugs and snails.

For the past years, the scientific travel agency Taxon Expeditions, in collaboration with Universiti Brunei Darussalam (UBD) has been organising biodiversity discovery trips for scientists, students, and laypersons to this forest. On the first trip, in 2018, during a night walk, participant Simon Berenyi, who runs an ethical pest control company in the UK, reached up to a dead leaf suspended over the trail. Everybody—the other participants, even the resident snail expert—had ducked and passed underneath this dead leaf without so much as giving it a glance. But something on its surface caught Simon’s eye. “Oi, is that a slug?” he exclaimed, and picked a slimy, well-camouflaged mollusc off it.

At the time, the team’s zoologists already suspected it was a new species – nothing like it had ever been found in this corner of the island. But that single specimen was not enough to publish its description as a new species. Over the years, successive expeditions to the same area came up with several more specimens of the same species, which made it clear that it was really a species never seen before.

On the 2022 expedition, a team composed of UBD students Nurilya Ezzwan and Izzah Hamdani and citizen scientist Harrison Wu from Virginia, USA, finished the description. Using the portable lab that Taxon Expeditions always carries with them, the team studied the animals’ shell, reproductive organs, and DNA, and prepared a paper for the open-access Biodiversity Data Journal, where it was published this week.

Citizen scientists from three continents help discover a new, giant slug from Europe

As usual on Taxon Expedition trips, on the last night the team voted on the scientific name for the new species. With an overwhelming majority, the ‘snug’ was named after Mr. Md Salleh Abdullah Bat, the field centre supervisor, who would retire just weeks after the team left. Mr. Salleh himself agrees that it is indeed a very fitting farewell gift.

Research article:

Schilthuizen M, Berenyi S, Ezzwan NSMN, Hamdani NIAA, Wu H, De Antoni L, Vincenzi L, de Gier W, van Peursen ADP, Njunjić I, Delledonne M, Slik F, Grafe U, Cicuzza D (2023) A new semi-slug of the genus Microparmarion from Brunei, discovered, described and DNA-barcoded on citizen-science ‘taxon expeditions’ (Gastropoda, Stylommatophora, Ariophantidae). Biodiversity Data Journal 11: e101579. https://doi.org/10.3897/BDJ.11.e101579

Photos by Pierre Escoubas

Follow Biodiversity Data Journal on social media:

Facebook

twitter

Alien land snail species are increasing exponentially

A new study compiles an overview of the exponential increase and dynamic spread of land snail species introduced to Europe and the Mediterranean.

Invasive land snail species can displace native species and harm human health. A recent study by the Leibniz Institute for Biodiversity Change Analysis (LIB) compiles an overview of the exponential increase and dynamic spread of land snail species introduced to Europe and the Mediterranean from other continents.

*Laevicaulis alte*, an invasive species from tropical Africa that was introduced into Egypt in 2018. © Reham F. Ali

To date, there is a lack of information for the spread of alien species, especially invertebrates such as snails. “Despite efforts to compile lists of alien species, there is not even a well-documented inventory of alien invertebrate species for Europe,” emphasizes Prof. Dr. Bernhard Hausdorf, section leader Mollusca at LIB. His study, just published in the journal NeoBiota, provides a basis for decisions on further measures to control or eradicate introduced populations.

Alien land snail species in the Western Palaearctic Region: Zonitoides arboreus, Hawaiia minuscula, Guppya gundlachii, Polygyra cereolus

Land snails play a supporting role in ecosystems. They decompose decaying plants and thus play an important role in nutrient cycling and soil formation. However, more and more species are being spread beyond their native range, usually by humans, sometimes intentionally, but often unintentionally by goods or travellers.

The study examines 22 land snail species introduced to Europe and the Mediterranean from other continents. Most of them are small, live on decaying plant parts and apparently cause few problems. In contrast, carnivorous species can threaten native species; and species that feed on living plants can cause damage to agriculture. Some even serve as hosts and vectors of parasites that can cause brain encephalitis, for example, and thus can indirectly harm human health.

Alien land snail species in the Western Palaearctic Region: *Paralaoma servilis* and *Helicodiscus parallelus*.

Harmful species include the Laevicaulis species recently introduced to the Mediterranean from tropical Africa and the African giant snail Lissachatina fulica. They can cause economic damage on irrigated farmland or in greenhouses by destroying or contaminating crops, making them unsaleable.

Hausdorf’s study compiles records of land snail species introduced to the Western Palearctic region, Europe and the Mediterranean, from other regions after 1492 and established in the wild. In doing so, he observes that the number of alien species has increased steadily since the 19th century, even exponentially from the 1970s onward, and that the introduced species have become more widespread.

Within Europe, alien species generally spread from south to north and from west to east. Thirteen of the 22 species studied were from North America, three from sub-Saharan Africa, two from the Australian region, three probably from the Oriental region, and one from South America.

Even if trade relations and the spread of species can be correlated, Hausdorf believes that the prevailing climate is primarily decisive: “The spread of many of the introduced species, especially the tropical species dispersing in Mediterranean, is probably favored by climate change.”

Bernhard Hausdorf, “Distribution patterns of established alien land snail species in the Western Palaearctic Region”, NeoBiota, Pensoft
https://doi.org/10.3897/neobiota.81.96360

Press release originally published by Leibniz Institute for the Analysis of Biodiversity Change. Republished with permission.

Follow NeoBiota on Facebook and Twitter.

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

Eco-certified Ashtamudi short-neck clam acquires its rightful identity

*Fishermen fishing Ashtamudi short-neck clam.*

Even though the short-neck clam is the major resource and export coming from Ashtamudi Lake in Kerala, India – the first fishery to be awarded with a a Marine Stewardship Council certification for sustainability in the country, a recent study found out that the mollusc had been subject to mistaken identity.

Further, this is not the first time when the species and genus name of this clam has been changed. At first, the species was identified as Paphia malabarica, which is also the name one could read in all hitherto published reports, including the Marine Stewardship Council’s register. Later on, as the name was proved to not be compliant with the current nomenclature, the Ashtamudi short-neck clam began to be referred to as Protapes gallus.

*Marcia recens from Ashtamudi lake, India.*

However, the latest in-depth taxonomic study points to the clam having been misidentified from the very beginning. According to the finding of the team of A. Arathi, R. Ravinesh and A. Biju Kumar of the Department of Aquatic Biology and Fisheries, University of Kerala, and Graham Oliver of National Museum Wales, United Kingdom, the Ashtamudi short-neck clam belongs to a totally different genus, while its rightful scientific name actually is Marcia recens. Their paper was published in the open access journal ZooKeys.

*Protapes gallus (Paphia malabarica) (above) and Marcia recens (below) showing obvious external morphological variations.*

During their research, the scientists identified another edible species from Ashtamudi Lake that belongs to the Marcia genus: Marcia opima. While it could easily be mistaken for its commercially important relative thanks to a multitude of colour variations, it does not appear to contribute significantly to the export. Meanwhile, the actual species identified as Paphia malabarica (Protapes gallus) can be found in shallow coastal waters in the south of the country, but not in the studied brackishwater lake.

“No deleterious effects on the viability of the fishery have resulted from this error in identification, but from a legislative perspective applying the incorrect name to the exploited species could undermine its certification and protection,” comment the researchers.

“On the basis of this study, the species involved in the Marine Stewardship Council certification would be better considered at the generic level of Marcia or at the species level for Marcia recens, the most dominant species in the Ashtamudi Lake clam fishery zone.”

In conclusion, the authors of the study say that, “misidentification can undermine comparative biological studies and conservation, while more molecular studies are required to resolve the taxonomy of all clams involved in fishery.”

###

Original source:

Arathi AR, Oliver PG, Ravinesh R, Kumar AB (2018) The Ashtamudi Lake short-neck clam: re-assigned to the genus Marcia H. Adams & A. Adams, 1857 (Bivalvia, Veneridae). ZooKeys 799: 1-20. https://doi.org/10.3897/zookeys.799.25829

Photos by Dr Biju Kumar.

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.

###

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

DNA study in the Pacific reveals 2000% increase in our knowledge of mollusc biodiversity

Lead author Dr Helena Wiklund examining specimens on the RV Melville in October 2013

Scientists working in the new frontier for deep-sea mining have revealed a remarkable 2000% increase in our knowledge of the biodiversity of seafloor molluscs.

The 21 mollusc species newly described thanks to the latest DNA-taxonomy methodology

Tweny-one species, where only one was previously known, are reported as a result of the research which applied the latest DNA-taxonomy methodology to mollusc specimens collected from the central Pacific Clarion Clipperton Zone (CCZ) in 2013. They are all described in the open access journal ZooKeys.

Among the discoveries is a monoplacophoran mollusc species regarded as a ‘living fossil’, since it is one the ancestors of all molluscs. This is the first DNA to be collected from this species and the first record of it from the CCZ mining exploration zone – a vast 5-million-km² region of the central Pacific that is regulated for seabed mining by the International Seabed Authority.

“Despite over 100 survey expeditions to the region over 40 years of mineral prospecting, there has been almost no taxonomy done on the molluscs from this area,” says lead author Dr Helena Wiklund of the The Natural History Museum in London (NHM).

Dr Wiklund undertook a comprehensive DNA-based study of the molluscs to confirm species identities and make data available for future taxonomic study. This was coupled with the expertise of the NHM’s Dr John Taylor, who led the morphological work.

The molluscs were found in samples taken on and in the mud surrounding the potato-sized polymetallic nodules that are present in high abundance across the CCZ. These nodules are the target for potential deep-sea mining being rich in cobalt, copper, nickel, manganese and other valuable minerals.

The data are vital for the future environmental regulation of deep-sea mining, but have also revealed surprising patterns.

“I was amazed to discover that specimens collected during the 19th century by HMS Challenger were probably the same as ours over a range of 7000 km, but that data lodged on genetic databases from closer but shallower depths is likely to be from a different species,” comments Dr Thomas Dahlgren, population geneticist at Uni Research, Norway and University of Gothenburg, Sweden, who studied in detail a species called Nucula profundorum.

“Our efforts are now focussing on studying the DNA from many more samples of this species to examine connectivity and potential resilience to deep-sea mining,” he added.

Dr Thomas Dahlgren sieving sediments to find new clam and snail species

“It is a simple truth that we cannot move forward on regulatory approval for deep-sea mining without fundamental baseline data on what animals actually live in these regions,” says Principal Investigator of the NHM Deep-sea Systematics and Ecology Research Group, Dr Adrian Glover.

“Our work has highlighted obvious gaps in our knowledge, but also shown that with even relatively modest effort, we can greatly increase our understanding of baseline biodiversity using DNA-taxonomy.”

Creating a library of archived DNA-sequenced samples from known species allows for the future possibility of using the latest environmental DNA (eDNA) methods to ‘search’ for these species using just tiny samples of mud or seawater.

“Its akin to forensic science’, says Dr Glover. “You can’t use eDNA to find the criminals or species unless you have a library of information to compare them too”.

All data and specimens from the study have been lodged at the NHM and online repositories to make them accessible for future study. Of particular importance are the frozen tissue collections, which are housed in the state-of-the-art Molecular Collections Facility at the NHM and available for loan or further DNA work.

Original source:

Wiklund H, Taylor JD, Dahlgren TG, Todt C, Ikebe C, Rabone M, Glover AG (2017) Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca. ZooKeys 707: 1–46. https://doi.org/10.3897/zookeys.707.13042

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.

As 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.

###

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

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.

###

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