Category: Subterranean Biology

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

An extraordinary cave animal found in Eastern Turkmenistan

A remote cave in Eastern Turkmenistan was found to shelter a marvelous cave-adapted inhabitant that turned out to represent a species and genus new to science. This new troglodyte is the first of its order from Central Asia and the first strictly subterranean terrestrial creature recorded in the country.

Kaptarhana cave is located at the foot of Koytendag Mountain, one of the most distinctive mountain landscapes in Central Asia. A curious amalgam of desert landscapes, often highly dissected by ravines, foothills with ridges, cuestas and fan plains, the mountain is a potential home to key biodiversity gems still awaiting discovery.

Also remarkable for its richness of caves and other limestone formations, Koytendag Mountain has more than 300 caves, sinkholes and potholes, hitherto registered from its territory, including the sixth largest cave system in Asia Gap Goutan/Promezdutachnaya stretched at more than 57 km underground. Also worthy of a mention is the beautiful cave Gulshirin, known for its snow white passages and extraordinary formations.

Another fine example, cave Kaptarhana, presents a unique habitat for a high number of cave-adapted animals, among which is the new species of a few millimetres long, pale and eyeless insect-like creature, whose relatives in the order Diplura also go by the name of two-pronged bristletails.

The scientists named it Turkmenocampa mirabilis, where the genus name (Turkmenocampa) refers to the creature’s country of origin (Turkmenistan), while the species name (mirabilis) means “unusual, amazing, wonderful, remarkable” in Latin to highlight its unique morphology and position among its relatives.

The new species is described in the open access journal Subterranean Biology by Dr. Alberto Sendra, University of Alcalá, Spain, Prof. Boris Sket, University of Ljubljana, and Prof. Pavel Stoev, National Museum of Natural History, Bulgaria.

In fact, Stoev and Sket were the first speleobiologists to visit and explore Kaptarhana in nearly 43 years. The survey was part of their study into the caves of Koytendag State Nature Reserve, Turkmenistan, conducted in 2015 and endorsed by a Memorandum of Understanding between the State Committee on Environment Protection and Land Resources of Turkmenistan and the Royal Society for the Protection of Birds.

To discover the new species, the scientists spent about 8 hours in the cave looking for specimens and placed pitfall traps with smelly cheese used as a bait. While visual observations had no success due to the cave being very spacious, a number of exemplars of the hitherto undescribed animal fell victims of the traps.

“What we have here is not only a new remarkable organism, but also an amazing and unusual cave critter that has undergone a long evolutionary journey to adapt to the underground environment of Central Asia,” says the lead author Alberto Sendra.

The authors see their latest discovery as a proof of the importance of Kaptarhana as a refuge for a number of endemic invertebrates and an opportunity to draw attention to its protection under the laws of Turkmenistan.

“While many speleobiologists consider the terrestrial cave fauna in Central Asia as poor, it is places such as Kaptarhana that can turn the tables by giving us new insights about the biodiversity richness, evolutionary history, formation and functioning of the underground ecosystems of this part of the world.” comments Stoev.

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Original source:

Sendra A, Boris Sket B, Stoev P (2017) A striking new genus and species of troglobitic Campodeidae (Diplura) from Central Asia. Subterranean Biology 23: 47-68. https://doi.org/10.3897/subtbiol.23.14631

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

First description and video of a rainbow boa preying on a vampire bat in a cave in Ecuador

While snakes are well-known enemies to bats, their preying on the winged mammals has hardly been recorded. Furthermore, no bat as big and heavy as the common vampire, has been described being killed and eaten prior to the present study, published in the open access journal Subterranean Biology.

The study, where scientists, led by Sarah Martin-Solano, Universidad de las Fuerzas Armadas, ESPE, Ecuador, record a rainbow boa catching the bat, is the first known such case to have taken place on a cave’s floor. The documented observation serves to confirm that snakes do predate on bats in caves, and is also the first such case known from Ecuador.

Apart from the detailed description, the scientists also provide a film, showing almost in full the event of a rainbow boa catching, killing and swallowing an adult female common vampire bat.

The predation has been observed in a 450-metre-long cave in Tena, Ecuador. There, an adult female common vampire bat, one of the three bat species to feed exclusively on blood, was seen to fly into the cave right over the boa’s head and its waiting open jaws, raised some 30-35 centimetres above the ground.

The approximately 140-centimetre-long snake snatched the bat by the head and immediately brought it down to the floor. Having been strangled by the boa, the bat appeared to give up its resistance about two minutes later, although the predator did not let it go for another seven minutes. Once assured the mammal is dead, the snake started trying different positions from which to fit the bat in its mouth. However, this seemed particularly difficult due to the mammal’s size and the stiffness of its shoulder joints.

Eventually, the rainbow boa began constricting the body once again. Then, starting from the head, the snake managed to swallow the whole bat in 4 minutes and 50 seconds, with the predation measured to last about 25 minutes in total.

In conclusion, the authors suggest that more research needs to be undertaken, so that scientists can find out how common is for snakes to prey on bats in caves.

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Original source:

Martin-Solano S, Toulkeridis T, Addison A, Pozo-Rivera WE (2016) Predation of Desmodus rotundus Geoffroy, 1810 (Phyllostomidae, Chiroptera) by Epicrates cenchria (Linnaeus, 1758) (Boidae, Reptilia) in an Ecuadorian Cave. Subterranean Biology 19: 41-50. doi:10.3897/subtbiol.19.8731