subterranean fauna

Exploring the hidden treasures of Aziza Cave: A biodiversity hotspot in North Africa

Aziza Cave harbors a rich and diverse array of subterranean life that is only now beginning to be revealed widely.

Guest blog post by Marconi Souza-Silva

Beneath the arid pre-Saharan zone of Morocco lies Aziza Cave, also known as Kef Aziza or Tazouguert Cave. The vast subterranean system stretches over 3.5 kilometers of surveyed galleries, making it Morocco’s fifth-largest cave system and one of the top ten most extensive caves in North Africa.

A view of the Sahara desert and Aziza cave’s entrance.

Beyond its sheer size and geological significance, Aziza Cave harbors a rich and diverse array of subterranean life that is only now beginning to be revealed widely. In a recent study in the journal Subterranean Biology, researchers cataloged the subterranean fauna of Aziza Cave and provided a detailed checklist of 26 different taxa potentially representing cave-restricted species. Among these are 22 troglobitic species, organisms that have adapted to life entirely within the cave environment, and four stygobitic species, which have specially evolved to live in the cave’s groundwater.

The discovery of such a variety of species highlights the cave as a critical biodiversity hotspot, not only in Morocco but for the African continent as a whole. One alarming aspect of this discovery is the large number of species that still need to be thoroughly studied or described.

Only about 34.6% of the species in Aziza Cave have been formally identified and described by scientists. Further research could lead to the identification and description of many new species. The fauna found in Aziza Cave includes a wide variety of life forms, with the richest groups being beetles (Coleoptera), spiders (Araneae), springtails (Entomobryomorpha), and woodlice (Isopoda). Some have evolved remarkable adaptations to their lightless, nutrient-scarce environment, such as reduced pigmentation, elongated appendages, and heightened sensory capabilities that help them navigate and survive in this extreme habitat.

Despite these discoveries, much of Aziza Cave remains unexplored. Large portions of this karstic system have yet to be surveyed, and researchers believe that the biodiversity uncovered so far is just the beginning. The cave’s unexplored depths likely hold many more secrets, including potentially new species that have yet to be seen by human eyes. This prospect has sparked great interest among speleologists and conservationists, who see Aziza Cave as an important research site for studying subterranean ecosystems.

The biodiversity of Aziza Cave is something to celebrate, but it also sheds light on the significant conservation challenges that subterranean habitats in Morocco and across North Africa are facing. Caves are delicate ecosystems that are highly sensitive to changes in their environment. Human activities such as pollution, mining, deforestation, and unsustainable tourism pose severe threats to these ecosystems and the species that depend on them. Once these habitats are damaged or destroyed, it is often impossible to restore them, and the species that inhabit them may face extinction.

Human-induced impacts have already begun to take their toll in Aziza Cave. Visitors can disrupt the delicate balance of the cave’s ecosystem, change water quality, or introduce pollutants and alien species. These pressures underscore the urgent need for conservation measures to protect this unique environment and its inhabitants. By highlighting the importance of Aziza Cave and similar habitats, the researchers hope to encourage further exploration and study of Africa’s subterranean ecosystems and develop effective conservation strategies to protect them. By protecting these fragile ecosystems and supporting scientific exploration, we can ensure that the incredible biodiversity of Aziza Cave and other subterranean habitats continues to thrive.

Research article:

Moutaouakil S, Souza-Silva M, Oliveira LF, Ghamizi M, Ferreira RL (2024) A cave with remarkably high subterranean diversity in Africa and its significance for biodiversity conservation. Subterranean Biology 50: 1-28. https://doi.org/10.3897/subtbiol.50.113919

Out of the dark: historical cave snail collection rediscovered in the attic

Stored in the attic for decades, the shell collection of Dominik Bilimek at BOKU University hides a plethora of untold narratives.

Guest blog post by Petra Lukeneder and Adrienne Jochum

During the past years, interest in the processing and preservation of historical, scientific collections has increased significantly. Fascinating and obscure treasures are stored along with their individual stories while splendid and exciting specimens eke out an existence in boxes and cellars. The scientific curation of the Dominik Bilimek (1813-1884) Collection at BOKU University (Vienna, Austria) is one such example. Stored in the attic for many decades, later stashed in the basement, surviving two floods, a plethora of untold narratives unfolded as the specimens were unpacked. For example, the story of the young, aspiring, Slovenian collector and researcher, Heinrich Hauffen (1836-1866), with his special interests in speleology and the fauna inhabiting the subterranean realm come to light.

A grainy black-and-white photograph of a bearded man. — The only known photograph of collector and naturalist Heinrich Hauffen (1836-1866) (Digital Library of Slovenia; reference number 5S74D58Z).

At first, it was just a label type in the collection that differed from the others. It was a multidisciplinary process to assign it to Hauffen. At that time, only few scientists were concerned with the genus Carychium, including Georg von Frauenfeld (1807-1873), Heinrich Freyer (1802-1866), and Meinrad Thaurer von Gallenstein (1811-1872), all of whom were names that were closely linked to Bilimek and his collection. Fortunately, Hauffen’s handwriting could be identified by using original manuscripts from the Archive of the National Museum of Slovenia.

In our work published in Subterranean Biology, we present our results on the rediscovery of historical material of Heinrich Hauffen, which turned out to be original material, that he used to describe the cave snail taxa Carychium reticulatum and Carychium reticulatum bidentatum. Today, the eastern Alpine and the Dinaric subterranean members of the genus Carychium are assigned to their own genus, Zospeum, based on their troglobiontic characteristics such as lack of eyes, colourless bodies, genetic data, and their totally different shell morphology.

A photograph of a tiny white snail attached to a rocky surface, with a yellow arrow to indicate the location of the snail — Live animal, indicated by the yellow arrow, of the genus *Zospeum* from Krska jama cave in Slovenia. The snail’s shell appears almost to be translucent.

This interdisciplinary work not only includes historical aspects, but also a collaboration with the Natural History Museum Vienna and the Department of Evolutionary Biology (University of Vienna) in conjunction with the taxonomic expertise from the Natural History Museum Bern (Bern, Switzerland), the Senckenberg Research Institute and Natural History Museum (Frankfurt am Main, Germany) and from the Zoologische Staatssammlung München (Münich, Germany). By using light microscopy, X-ray Micro-CT data and SEM in sync with Hauffen’s original figures and handwritten documents, the morphological analysis of C. reticulatum illustrates the degree of phenotypic variation on the shells of individuals from two different cave populations of the species Zospeum spelaeum. The species Carychium bidentatum is considered a junior synonym of Zospeum costatum.

Photographs of people taking samples from caves. — Cave snail collection during field work in Slovenia and Spain.

The genus Zospeum constitutes a radiation of minute, glassy troglobitic snails (Ellobioidea) endemic to the Eastern Alps and the Dinaric Alps, extending as far west as Lake Garda in Italy and as far south as Montenegro. So far, 38 species of Zospeum have been described. Morphologically, the most informative diagnostic characters are apertural form and the degree of coiling and the shape of the columella (inner spindle) as well as the presence and configuration of the lamella in relation to it. In the Pre-Micro-CT era, one had to poke windows into the shells to view these signatory structures. Valuable material could become damaged, and many taxonomists shied from risky mishaps to assess the tiny shells (< 1.5 mm). This present work demonstrates the efficacy of fine-resolution imagery to assess valuable historic material.

A photograph of a woman walking past drawers of specimens — Archive of the Institute of Applied Geology (BOKU University), where the Bilimek Collection including Hauffen’s material, is being stored and processed. Photo by Radek Polách, Muzea Novojičínska.

Hauffen died at the age of 30 as part of the Austrian volunteer corps in Mexico – with the prospect of a permanent position at the Mexican National Museum. According to current knowledge, this is the reason why the Hauffen collection was passed on to Bilimek, who returned to Europe in 1867. There are still abundant specimens, often from localities that cannot longer be sampled nowadays, from Hauffen within the Bilimek collection. In the future, this part can hopefully be separated and scientifically processed as well.

Research article:

Lukeneder P, Ottner F, Harzhauser M, Winkler V, Metscher B, Ruthensteiner B, Jochum A (2024) Lost & Found – Rediscovery of H. Hauffen’s Carychium material in the Dominik Bilimek Collection, BOKU University, including a contemporary assessment within the genus Zospeum (Gastropoda, Ellobioidea, Carychiinae). Subterranean Biology 49: 97-116. https://doi.org/10.3897/subtbiol.49.130692

Virginia Tech researcher discovers new millipede species in the Los Angeles metropolis

Little is know about the creatures that crawl through the soil under our feet, even in a city like Los Angeles.

In busy Los Angeles, few people pay attention to what’s under their feet, but a new underground movement has people looking at the subterranean world just below the surface. A team of scientists discovered a new species of millipede crawling just beneath the soil surface in Los Angeles and Orange counties.

These never-before-seen creatures are pale, blind, thin, inch-long burrowers with the ability to produce a silk-like sticky substance, similar to spider silk. Measuring in at 0.5 millimeters wide and 2 1/2 centimeters long, these creatures are about the width of the a thin graphite lead of a mechanical pencil and about as long as a small paperclip.

The Los Angeles Thread Millipede’s size compared with a nickel. Photo by Paul Marek for Virginia Tech

Despite being so small, they are described as having a gaping toothy mouth and over 480 legs. The species in question is called the Los Angeles Thread Millipede, formally named Illacme socal.

Paul Marek, associate professor in the Department of Entomology in the College of Agriculture and Life Sciences at Virginia Tech, was the lead author of the study that described the new millipede.

This minute critter, the Los Angeles Thread Millipede has gone unnoticed beneath feet until now. Photo by Paul Marek for Virginia Tech

“We hope that this discovery will encourage conservation efforts to protect these unique creatures and their habitats,” said Marek. “The discovery of Illacme socal highlights the importance of research into subterranean fauna.”

The discovery of Illacme socal was made possible by funding from the National Science Foundation. The research team included scientists from Virginia Tech, West Virginia University, and the University of California, Berkeley. The findings were published in the journal ZooKeys.

The team captured a video of the millipede burrowing and moving through small spaces and crevices underground. This is the first-ever video of this species in action and provides insight into the unique behaviors of these fascinating creatures.

This research discovery highlights the importance of habitat preservation efforts to protect the environment and prevent the loss of biodiversity. The millipede was found in two parks in the Los Angeles and Orange counties but almost certainly lived in other parts of the metropolis in the past.

The fact that populations of this species is living in two small well-known areas that are near constant development emphasizes the need for conservation efforts to protect this and other threatened organisms.

Research article:

Marek PE, Hall CL, Lee C, Bailey J, Berger MC, Kasson MT, Shear W (2023) A new species of Illacme from southern California (Siphonophorida, Siphonorhinidae). ZooKeys 1167: 265-291. https://doi.org/10.3897/zookeys.1167.102537

Press release originally published by Virginia Tech. Republished with permission.

Knowledge is power: How can we make cave tourism more environmentally friendly?

A new study in Nature Conservation presents a literature-based dataset on the ecological status of 265 show caves in 39 countries across the world.

Throughout history, people have used caves for a number of reasons: as shelters, places for rituals, food storage, and, in more recent times, as touristic attractions. In these so-called show caves, visitors can experience the natural beauty of caves, usually by following a guide on constructed, artificially lit trails.

But caves are also very fragile ecosystems, bursting with underground life. They are home to numerous invertebrate and bat species, including ones that are threatened or endemic. The human disturbances caused by the changes in the infrastructure and environment, coupled with the influx of tourists, often affect the ecological processes and, consequently, these organisms. But how much do we know about the influence of tourists on cave ecosystems?

According to a new study in the open-access journal Nature Conservation, not enough.

Apart from affecting subterranean invertebrates, the artificial lighting and noise related to tourist visits may also affect the life of bats, making it harder for them to reproduce or overwinter in caves.

Going through more than 1,000 scientific papers, an Italian team of scientists, led by Marco Isaia and Elena Piano from the University of Torino, prepared a literature-based dataset relative to the knowledge on the ecological status of 265 show caves in 39 countries across the world. Their database includes a georeferenced set of show caves, where researchers have evaluated a number of environmental indicators that help monitor the impact of tourism and its related activities on subterranean ecosystems. They also list cave characteristics for each cave, including its natural heritage that attracts tourists.

There are many ways in which tourism can disturb life in a cave. For example, the presence of visitors may help increase cave temperature, which, combined with the increase of CO₂ air concentration caused by tourists’ breath, may enhance carbonate dissolution, damaging geological formations. Moreover, tourists can carry pollutants and propagules of microorganisms into the cave through their clothes and hands, which then land on geological formations, in the water, in the air, and on the ground. Apart from affecting subterranean invertebrates, the artificial lighting and noise related to tourist visits may also affect the life of bats, making it harder for them to reproduce or overwinter in caves.

The dataset published in Nature Conservation set a baseline towards the integrated and multidisciplinary study of the impacts caused by tourism on these fragile ecosystems, but the research team points out that much remains to be done. For example, they found out that there wasn’t enough research on show caves outside of Europe, or on the possible impacts of tourism on the subterranean fauna in the context of climate change.

Ultimately, the data in this study can help managing authorities come up with guidelines that will allow a sustainable touristic development of show caves, not only from an environmental perspective, but also from an economic and social point of view.

“Overall, this data paper could fill the lack of awareness towards the fragility of the natural heritage of show caves to favour a sustainable touristic use that would guarantee their preservation for future generations as well as the economic development of local communities”, the authors conclude.

Research article:

Piano E, Nicolosi G, Mammola S, Balestra V, Baroni B, Bellopede R, Cumino E, Muzzulini N, Piquet A, Isaia M (2022) A literature-based database of the natural heritage, the ecological status and tourism-related impacts in show caves worldwide. Nature Conservation 50: 159-174. https://doi.org/10.3897/natureconservation.50.80505

All images are from Bossea show cave in Italy, by Simone Marzocchi.

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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

Out of the darkness: A new spider found deep within an Indiana cave

Lead author Marc Milne in the Stygian River Cave and a male specimen of the newly described *Islandiana lewisi*

Spiders are ubiquitous within our forests, fields, and backyards. Although you may be used to seeing the beautiful yellow and black spiders of the genus Argiope in your garden, large ground-scurrying wolf spiders in your yard, or spindly cellar spiders in your basement, this new sheet-web-building spider is probably one you haven’t seen before. The reason is that it’s known from a single cave in the world, Stygeon River Cave, in southern Indiana.

The University of Indianapolis assistant professor, Dr. Marc Milne, described the rare species in the open access journal Subterranean Biology with the help of a University of Indianapolis alumnus, Elizabeth Wells, who illustrated the spider for the manuscript.

Sheet weavers, also known as dwarf spiders or money spiders, are minute creatures growing no larger than a few centimetres in length, which makes them particularly elusive. Their peculiar webs are flat and sheet-like, hence their common English name.

Female of the new species *Islandiana lewisi*

The new spider, Islandiana lewisi, is an homage. Milne was shown the spider by a fellow scientist, Dr. Julian Lewis, who noticed the critter on one of his many cave expeditions. In appreciation for his help, Milne and Wells named the spider after Lewis.

This is the fifteenth species in its genus (Islandiana) and the fifth known to live exclusively in caves. It has been over 30 years since the last species has been added to this group.

At about 2 mm in size, Islandiana lewisi is thought to feed on even smaller arthropods, such as springtails living in the debris on the cave floor. It is unknown when it reproduces or if it exists anywhere else. The spider is likely harmless to humans.

The collectors of the spider, Milne and Lewis, described the hostile conditions within the cave, which the new species calls home: “because the cave floods from time to time, the insides were wet, muddy, slippery, and dangerous to walk on without the proper equipment.”

Milne and Lewis found the spider in small, horizontal webs between large, mud-caked boulders in the largest room in the cave. It was collected in October 2016 with the permission of the landowner.

Milne hypothesized that he had collected something special, stating, “I didn’t know what the spider was at first, I just thought it was odd that so many were living within this dark cave with no other spider species around.”

After returning to the lab and inspecting the spider under a microscope, Milne initially misidentified the species. However, when he re-examined it months later, he realized that the species was indeed new to science.

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Original source:

Milne MA, Wells E (2018) A new species of spider (Araneae, Linyphiidae, Islandiana) from a southern Indiana cave. Subterranean Biology 26: 19-26. https://doi.org/10.3897/subtbiol.26.25605

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