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.

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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

Guest Blog Post: New Area of Importance for Bat Conservation in Honduras

The recognition of the “Ceguaca, la Mujer de los Juncos” locality comes as a result of research work – published last year in Subterranean Biology – which produced the first checklist of bats for Santa Bárbara


Guest blog post by Eduardo Javier Ordoñez-Trejo and Manfredo Alejandro Turcios-Casco


Bat populations are threatened due to fragmentation and loss of their habitats. Meanwhile, dry forests are some of the least studied and most threatened ecosystems in Honduras, and similarly, so have been the caves.

We had to walk at least two hours to reach either of the caves in El Peñon or Quita Sueño, so we would take our full equipment: for camping, cooking and studying bats.
Photo by Hefer Ávila

Caves are important reservoirs of species, as they offer perks no other habitat can provide at once: a refuge from predators, inconstant weather, and a critical venue for social interactions, reproduction, hibernation, roosting and nutrients. In order to protect bat populations, the Latin American and Caribbean Web for Bat Conservation (RELCOM) supports the establishment of Areas of Importance for the Conservation of Bats, abbreviated as AICOMS (Spanish for Areas with Importance for the Conservation of Bats) .

It was at least a two-hour walk between the caves of Monte Grueso and the caves of El Peñon. The final stint, though, included a swim across Rio Ulúa, one of most extensive rivers in Honduras.
Photo by Hefer Ávila

Together with biologists of the National Autonomous University of Honduras (UNAH) and local community members, we provided the first ever checklist of bat species in the Dry Forest of Ceguaca, Santa Barbara (Honduras), and described the importance of two caves in the area for bat conservation based on species richness. We published this study last June in Subterranean Biology.

The study is openly accessible in Subterranean Biology

We found that caves in Ceguaca are inhabited by at least 23 bat species of four families, which represents approximately a fifth of all species known from Honduras. Their inhabitants include several threatened species like the hairy-legged vampire bat (Diphylla ecaudata), one of the three existing vampire bats, and rare species with few official records in the area, such as Schmidts’s big-eared bat (Micronycteris schmidtorum). These caves may also represent a critical site for roosting and nursing. During our study, we managed to record pregnant and lactating females of several species, as well as reproductive males.

The certificate issued by RELCOM recognising the caves in Ceguaca as an Area of Importance for the Conservation of Bats, dated 6th March 2020

“It feels wonderful to see that our work has had great results and that with our efforts, we established an area where bats will be protected and studied. This certification also includes the name of Roberto Castellano, an elder member of the community of Ceguaca, who helped us during the fieldwork as our guide. He was a great conservationist of this area and protector of the caves. Unfortunately, he passed away during the study, however, due to his enormous contribution, we dedicated our article to him and included him as part of this AICOM success.”

José Alejandro Soler Orellana, co-author of the study.

Using what we learned in Ceguaca’s caves, we approached the Program for Bat Conservation of Honduras (PCMH) and showed them the evidence the locality was indeed a precious place with a spectacular bat diversity. Consequently, thanks to our collaboration with the PCMH, the site was effectively declared as an Area of Importance for the Conservation of Bats by RELCOM on 6th March 2020. 

This is an enormous step for bat conservation in the country. Bat conservation efforts should focus on studying and protecting these and other important habitats. We also need to make sure that local people appreciate the important role the bats play in the ecosystem.

A close up of a spider

Description automatically generated
We captured this adult Pallas’s long-tongued bat (Glossophaga soricina) female in a cave in Monte Grueso. She must have been returning to the cave after spending the day pollinating local plants. During these surveys, we found trees with opened flowers of Mexican calabash (Crescentia alata).
Photo by Hefer Ávila

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Research article:

Turcios-Casco MA, Mazier DIO, Orellana JAS, Ávila-Palma HD, Trejo EJO (2019) Two caves in western Honduras are important for bat conservation: first checklist of bats in Santa Bárbara. Subterranean Biology 30: 41–55. https://doi.org/10.3897/subtbiol.30.35420

Cave fights for food: voracious spiders vs assassin bugs

Killing and eating of potential competitors has rarely been documented in the zoological literature, even though this type of interaction can affect population dynamics. In a recent publication in the open-access journal Subterranean Biology, Brazilian scientists presented their notes regarding the predation of an assassin bug by a spider in Neotropical caves. Underground, where food resources are scarce, such events might be possible as a result of ecological pressures imposed by the hostile environment, hypothesise the researchers.

Killing and eating of potential competitors, also known as intraguild predation, is a rare event that occurs only in specific situations such as severe scarcity of food resources, resulting in the competition between predators.

A recent paper in the open-access journal Subterranean Biology examines the case of a wandering spider species (Enoploctenus cyclotorax) seen to prey upon assassin bugs (Zelurus diasi) in a limestone cave in Brazil.

Even though such type of ecological interaction is uncommon, it is potentially important since it may decrease the competition between apex predators and thus, affect their population dynamics. Zelurus and Enoploctenus are voracious predators with a wide distribution in caves and epigean environment. Both of them have similar diets. In normal conditions, spiders reject assassin bugs as potential prey, so intraguild predation cases occur only in very specific situations.

From the perspective of the participants, intraguild predation is a dangerous strategy because the prey is also a predator, armed and capable to kill. However, in caves, this could be a very useful behaviour since food resources are scarce and have low density.

“This may be an important factor, maintaining the species in that challenging environment”, concludes lead author of the study Dr. Leopoldo Ferreira de Oliveira Bernardi.

The scientists suggest that probably prey scarcity has left little choice for spiders, and that’s why they ended up using unconventional type of prey in their diet.


Intraguild predation between female Enoploctenus cyclotorax and adult Zelurus diasi observed during the study.
Credit: Leopoldo Ferreira de Oliveira Bernardi
License: CC-BY 4.0

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Original source:

Bernardi LFO, Sperandei VF, Audino LD, Sena CH, Alves JA (2020) Notes on the predation of an assassin bug by a spider in a Neotropical cave. Subterranean Biology 33: 17-22. https://doi.org/10.3897/subtbiol.33.48292



New blind and rare planthopper species and genus dwells exclusively in a Brazilian cave

This cave planthopper species new to science is only the second dwelling exclusively in the subterranean depths of Brazil from its family. Surviving without seeing the light of the day at any point of its life, this species has neither the eyes, nor the vivid colouration, nor the functional wings typical for its relatives.

Yet, these are only part of the reasons why the new planthopper needed to have a separate new genus established for itself. The new species is described by a research team from the Center of Studies on Subterranean Biology, Brazil, in the open access journal Deutsche Entomologische Zeitschrift.

The planthopper is called Iuiuia caeca, with the genus name (Iuiuia) referring to the locality, where it was found, and its species name (caeca) translating to ‘blind’ in Latin. It is predominantly yellowish insect that measures only 3 mm, which is small even by planthopper standards.

At first glance, the new cave planthopper appears as if it has been hiding from human eyes all along. So far, it has been located in a single cave in the Iuiú municipality, Bahia state, Brazil, where the team of Prof. Rodrigo Ferreira, Federal University of Lavras (UFLA), Brazil, spotted the insect. He then contacted cave planthopper specialist at the Museum für Naturkunde, Berlin, Prof. Hannelore Hoch, and collaboratively they decided to document and describe the new species. The limestone cave is yet to be fully explored since it floods during the rainy periods.Image 2

In the meantime, the cave’s only entrance is a small opening, which, on the other hand, clearly imposes a huge stability to the atmosphere. Moreover, although the researchers visited the cave on five occasions, they managed to find the species on two of them only. The planthopper was nowhere to be find in the neighbouring subterranean habitats either, which strongly suggests that it is a rare short-range endemic.

Being such a rarity, the blind new planthopper ought to be on the conservation radar. Although the scientists did not notice any signs of the cave having ever been visited by humans before; and its immediate surroundings have not been impacted by mining activities, yet, such threat is not to be excluded. In fact, the area is being currently evaluated for its potential for limestone extraction.

“It is to be hoped that legal measures for the conservation of the subterranean fauna of Brazil – which constitutes one of the country’s unique biological resources – will be developed and consequently reinforced,” conclude the authors.

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Original source:

Hoch H, Ferreira RL (2016) Iuiuia caeca gen. n., sp. n., a new troglobitic planthopper in the family Kinnaridae (Hemiptera, Fulgoromorpha) from Brazil. Deutsche Entomologische Zeitschrift63(2): 171-181. doi: 10.3897/dez.63.8432

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

Smeagol found underground in Brazil: New eyeless and highly modified harvestman species

Called after Tolkien’s character from the “Lord of the Rings” series, a new eyeless harvestman species was found to crawl in a humid cave in southeastern Brazil. Never getting out of its subterranean home, the new daddy longlegs species is the most highly modified representative among its close relatives and only the second one with no eyes living in Brazil. Its introduction to science, made by the Brazilian research team of Dr. Ricardo Pinto-da-Rocha, Instituto de Biociências da Universidade de São Paulo together with Dr. Maria Elina Bichuette and MSc. Rafael Fonseca-ferreira from Universidade Federal de São Carlos (UFSCar), is published in the open-access journal ZooKeys.

While there are cave dwellers that can easily survive above the ground and even regularly go out in order to feed or mate, there are some, such as the new harvestman species, Iandumoema smeagol, that never leave their subterranean habitats. As an adaptation, the new harvestman species is eyeless and has a reduced amount of melanistic pigmentation, which shows through its pale yellowish colours.

The fourteen adult and juvenile individuals, observed by the researchers, were noticed to always stay close to the stream, most often preferring the wet cave walls. While the juveniles appeared quite active, the adults showed a more sedentary behaviour.

Typically for the harvestmen, the new species was found in a cave with organic matter deposits or spots. On one occasion the team observed one of the individuals in such litter, where it was scavenging carcasses of invertebrates.

In conclusion, the authors point out that additional studies on the population biology of the new species are urgent so that an adequate conservation strategy can be assumed. It is probable that its highly restricted distribution along with the deforestation taking place in the cave’s immediate surroundings call for the creation of protected areas.

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Original source:

Pinto-da-Rocha R, Fonseca-Ferreira R, Bichuette ME (2015) A new highly specialized cave harvestman from Brazil and the first blind species of the genus: Iandumoema smeagol sp. n. (Arachnida, Opiliones, Gonyleptidae). ZooKeys 537: 79-95. doi: 10.3897/zookeys.537.6073

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.

Underground gourmet: Selected terrestrial cave invertebrates and their meal preferences

Doubting whether terrestrial cave invertebrates feed on just anything they can find in the harsh food-wise environment underground, Dr. Jaroslav Smrz, fromCharles University, Vinicna, and his international team conducted a research in Slovakian and Romania caves. They tested the hypothesis that these species have rather negligible selection of food. Their microanatomical research into the gut content of several microwhip scorpions, oribatid mites, millipedes, springtails and crustaceans showed, however, that there is an evident meal preference among the species.

The results confirmed that the studied groups can adapt and develop under the pressure of extreme environmental factors. Therefore, the researchers concluded a low level of food competition. The study is available in the Subterranean Biology open-access journal.

The scientists studied the cells and tissues of the selected invertebrates and found out that the gut contents were nearly identical between the representatives of each group. This was the case even when the specimens had been collected from various locations. For instance, all microwhip scorpions proved a preference for cyanobacteria, while the mites favored the bacteria found in bat guano and the millipedes – fungi.

“The limited food offer seems to be used very unambiguously and thoroughly by the invertebrate communities,” the research team explained. “Therefore, the competition for food can be actually regarded as very low,” they concluded.

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Original source:

Smrz J, Kovac L, Mikes J, Sustr V, Lukesova A, Tajovsky K, Novakova A, Reznakova P (2015) Food sources of selected terrestrial cave arthropods. Subterranean Biology 16: 37-46. doi:10.3897/subtbiol.16.8609