subterranean species

The first cave-bound mollusc species from the Americas

Against the odds, a study by Brazilian researchers describes a new to science species of evidently cave-bound – or troglobitic – clam from northern Brazil.

Exclusively subterranean bivalves – the group of molluscs comprising clams, oysters, mussels, scallops – are considered a rarity. Prior to the present study, there had only been three such species confirmed in the world: all belonging to a small-sized mussel genus known from southeastern Europe. Furthermore, bivalves are not your typical ‘underworld’ dweller, since they are almost immobile and do not tolerate environments low in oxygen.

Against the odds, a recent study by Dr. Luiz Ricardo L. Simone (Museum of Zoology of the University of São Paulo) and Dr Rodrigo Lopes Ferreira (Federal University of Lavras), published in the open-access scholarly journal Subterranean Biology, describes a new to science species of evidently cave-bound – or troglobitic – clam from northern Brazil.

Small individuals of the newly described clam species Eupera troglobia sp. n. exposed to the air, next to a harvestman (Eusarcus sp.). Photo by Rodrigo Lopes Ferreira.

Named Eupera troglobia, the mollusk demonstrates features characteristic for organisms not meant to see the daylight, including lack of pigmentation, reduced size, delicate shell and fewer, yet larger eggs.

Curiously, it was back in 2006 when a report presenting a faunal survey of a cave in northern Brazil featured photographs of what was to be described as Eupera troglobia. However, the evidence was quickly dismissed: the clam must have been carried into the cave by water.

A submerged specimen of the newly described cave-bound clam species Eupera troglobia sp. n.

In 2010, Dr Rodrigo Lopes Ferreira accessed the report and noticed the depigmentation of the clams. Wondering whether it was indeed possible that he was looking at a troglobite, he searched amongst the collected specimens from that study, but could not find any of the discoloured bivalve.

Ten years later, his team visited the cave to specifically search for depigmented shells. Although the cave was partially flooded, the researchers were able to spot the specimens they needed attached to the walls of the cave.

In conclusion, the scientists highlight that their discovery is the latest reminder about how important the conservation of the fragile subterranean habitats is, given the treasure troves in their holdings.

Meanwhile, recently amended laws in Brazil put caves at considerably higher risk.

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Research paper:

Simone LRL, Ferreira RL (2022) Eupera troglobia sp. nov.: the first troglobitic bivalve from the Americas (Mollusca, Bivalvia, Sphaeriidae). Subterranean Biology 42: 165-184. https://doi.org/10.3897/subtbiol.42.78074

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King of the Cave: New centipede on top of the food chain in the sulphurous-soaked Movile

A new species of endemic, troglobiont centipede was discovered by an international team of scientists in the Romanian cave Movile: a unique underground ecosystem, isolated several millions years ago during the Neogene, whose animal life only exists because of the chemosynthetic bacteria. As the largest Movile’s inhabitant, the new species can easily be crowned as the ‘king’ of this ‘hellish’ ecosystem. Aptly named Cryptops speleorex, the cave-dweller is described in the open-access, peer-reviewed journal ZooKeys.

A photo of the newly discovered species (*Cryptops speleorex*), the largest inhabitant of the Movile cave (Romania) known to date
Photo by Mihai Baciu

Deemed to never see the light of the day, a new species of endemic, troglobiont centipede was discovered by an international team of scientists in the Romanian cave Movile: a unique underground ecosystem, where the oxygen in the air might be half of the amount of what we’re used to, yet the sulphurous abounds; and where the animal life only exists because of chemosynthetic bacteria feeding on carbon dioxide and methane.

This hellish ecosystem–where breathing alone could be lethal for most of us–seems to have finally crowned its king. At a size of between 46 and 52 mm in length, the centipede Cryptops speleorex is the largest of the cave’s inhabitants known to date. The new species is described in the open-access, peer-reviewed journal ZooKeys.

Already isolated from the outside world several millions years ago during the Neogene, the Movile cave has been drawing the attention of scientists ever since its unexpected discovery in 1986 by Romanian workers, searching for locations suitable for building a power plant in the southeastern parts of the country.

Surprisingly enough, despite its harsh living conditions, the Movile ecosystem was soon found to harbor a diverse and unique fauna, characterised by exceptional species endemism and specific trophic links. So far, the cave has been known to give home to the troglobiont water scorpion, liocranid and nesticid spiders, cave leeches and certainly many more yet to be discovered.

In fact, it was long thought that this unique underground ecosystem was also inhabited by surface-dwelling species widespread in Europe. Convinced that this scenario is highly unlikely, scientists Dr Varpu Vahtera (University of Turku, Finland), Prof Pavel Stoev (National Museum of Natural History, Bulgaria) and Dr Nesrine Akkari (Museum of Natural History Vienna, Austria) decided to examine a curious centipede, collected by speleologists Serban Sarbu and Alexandra Maria Hillebrand, during their recent expedition to Movile.

“Our results confirmed our doubts and revealed that the Movile centipede is morphologically and genetically different, suggesting that it has been evolving from its closest surface-dwelling relative over the course of millions of years into an entirely new taxon that is better adapted to life in the never-ending darkness,” explain the researchers.

“The centipede we described is a venomous predator, by far the largest of the previously described animals from this cave. Thinking of its top rank in this subterranean system, we decided to name the species Cryptops speleorex, which can be translated to the “King of the cave”, they add.

The scientists exploring the Movile cave (Romania)
Photo by Mihai Baciu

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Original Source:

Vahtera V, Stoev P, Akkari N (2020) Five million years in the darkness: A new troglomorphic species of Cryptops Leach, 1814 (Chilopoda, Scolopendromorpha) from Movile Cave, Romania. ZooKeys 1004: 1-26. https://doi.org/10.3897/zookeys.1004.58537

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

Ice Age survivors or stranded travellers? A new subterranean species discovered in Canada

The discovery of a new to science species of rare and primitive arthropod from the depths of a cave that was covered by a thick ice sheet until recently is certain to raise questions. In their study, published in the open-access journal Subterranean Biology, entomologist Alberto Sendra and local caver Craig Wagnell describe a new species of cave-dwelling, insect-like campodeid dipluran from the island of Vancouver (Canada) and discuss its origin.

According to the study, the dipluran’s presence could either mean that terrestrial arthropods have indeed been able to survive within the deep subterranean habitats during the Last Glacial Maximum period some 26,500 years ago or it is the result of related species having dispersed to the area during the deglaciation, making their way from as far as Asia.

Contrary to most people’s expectations, the new creature was discovered only an easy hike away from the nearest town of Port Alberni (Vancouver Island, British Columbia). There, cavers Craig Wagnell, Tawney Lem and Felix Ossigi-Bonanno from the Central Island Caving Club, together with Alberto Sendra, Alcala University (Spain), reported a remarkable, previously unknown species of dipluran from a couple of caves recently unearthed in the small limestone karstic area.

*The exit of the Kiku Pot cave (Vancouver Island, British Columbia, Canada).*

Named Haplocampa wagnelli, the new species pays tribute to co-author Craig Wagnell, “who has dedicated many years sampling and exploring in Vancouver Island caves”.

Unlike most cave-adapted campodeid diplurans, whose bodies and appendages are characteristically elongated and slender – a “trademark” feature for strictly underground arthropods – the new species has only slightly elongated antennae and legs and a thicker body. This is the reason why the researchers conclude that the species is not exclusively subterranean and is likely to also be present in soil habitats. On the other hand, its North American sister species seem to be even less adapted to life underground.

Interestingly, the scientists note close relationships between the genus (Haplocampa) of the new species and three others known from the two sides of the north Pacific Ocean: Pacificampa (Japanese Islands and the Korean Peninsula), Metriocampa (Siberia) and Eumesocampa (North America). According to the team, this is evidence for dispersal events where populations would cross over the old Bering Land Bridge, which used to connect America and Asia.

Furthermore, the new species is also one of the most northerly cave-adapted dipluran species, found at a latitude of 49º north. Some 26,500 years ago, its modern habitat would have been located underneath the Cordilleran Ice Sheet, part of the Late Wisconsinan North American ice sheet complex.

*Felix Ossigi-Bonanno and Craig Wagnell at the entrance of the Kiku Pot cave after their successful discovery (Vancouver Island, British Columbia, Canada).*

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Original source:

Sendra A, Wagnell C (2019) The cave-dwelling dipluran (Diplura, Campodeidae) on the edge of the Last Glacial Maximum in Vancouver Island caves, North America (Canada). Subterranean Biology 29: 59-77. https://doi.org/10.3897/subtbiol.29.31467

Saving the Underworld: Clarifying the subterranean fauna classification for improved conservation

Inevitably, many habitats, including the particularly vulnerable subterranean ones, will continue being erased from our planet as a result of human activities and interests. The challenge is to protect the ones that are the sole habitats to certain organisms, so that their species are safe from extinction. Hence, it is essential that the distribution of every each one of them is clearly defined.

Brazilian scientists Prof. Eleonora Trajano, Universidade Federal de São Carlos, and Prof. Dr. Marcelo Rodrigues de Carvalho, Universidade de São Paulo, discuss the current classification system, its application and complexities in a paper published in the open access Subterranean Biology.

Nowadays, there are three categories of subterranean fauna accepted. Troglobites live exclusively underground and are usually characterised with reduced or lacking eyes and pale or transparent colors; troglophiles may live both in caves and on the surface, with individuals commuting between these habitats and promoting genetic interchange between subterranean and surface populations; trogloxenes use caves regularly, but must leave them periodically in order to complete their life cycle.

Throughout the years, many alterations and subdivisions have been applied to the classification used when determining whether a cave organism belongs exclusively to the subterranean habitat, or not, before concluding these three groups, also known as the Schiner-Racovitza system. It is important to separate them properly, since the destruction of a habitat to an endemic troglobite, for instance, would immediately wipe out its whole species, as it would be impossible for the animals to move away.

However, many historic publications do not feature enough details about the described species’ distribution, nor identification of the used classification, so that the information is unreliable. Furthermore, there have been times, when people have been even afraid to survey the underground habitats, led by beliefs and associations linking caves to the “World of the Dead”.

In their paper, the authors conclude that the only way to define the species status of subterranean organisms with certainty is to study each species’ dynamics over a period of at least three years, since animals may migrate on a seasonal and/or non-seasonal basis. Also, scientists need to study thoroughly the area outside the surveyed cave, while testing for sampling sufficiency at all times.

“When employing classifications of subterranean organisms, especially for conservation purposes, these conditions should be checked for reliability of the status attributed to them,” say the authors. “Misplacing these organisms within the Schiner-Racovitza categories impairs the efficiency of such policies.”

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Original source:

Trajano E, Carvalho MR (2017) Towards a biologically meaningful classification of subterranean organisms: a critical analysis of the Schiner-Racovitza system from a historical perspective, difficulties of its application and implications for conservation. Subterranean Biology 22: 1-26. https://doi.org/10.3897/subtbiol.22.9759