cave species

A New Species of Fly Found on the Lesser Brown Horseshoe Bat

A bizarre new species of parasitic fly sheds its wings and legs to live permanently embedded in a bat’s ear.

Imagine a fly that decides flying is overrated. Instead, it finds a bat, sheds its wings, drops its legs, and burrows into the host’s skin for the rest of its days. This is the reality of the genus Ascodipteron, a group of highly specialised bat flies that challenge our basic definition of what an insect looks like.

In a recent study published in the open-access journal ZooKeys, researchers led by Haoran Sun of Beijing Forestry University have identified a new member of this strange family in the Yunnan Province of China. It brings some fascinating, if slightly macabre, biological quirks to the table.

The newly discovered species has been named Ascodipteron euryale and was found on the lesser brown horseshoe bat, known scientifically as Rhinolophus stheno. This discovery is particularly significant because it represents the first time a fly from this genus has been documented on this specific species of bat. These flies often show an incredibly narrow host range and a strict preference for where they live on the bat’s body. In the case of Ascodipteron euryale, they prefer the base of the bat’s ear, the tragus, or the ear pinna.

*Ascodipteron* *euryale* sp. nov. and its host *Rhinolophus* *stheno*. (Image credit: Haoran Sun et al.).

The life of a female Ascodipteron fly is especially interesting. After a very brief period of seeking out a host, the female undergoes a radical transformation into what scientists call a neosome. It essentially becomes an endoparasite, embedded so deeply in the bat’s tissue that often only its posterior end is visible, protruding slightly so it can breathe and release larvae. This particular species was discovered in Xianren Cave, located in the Simao District of Pu’er City, at an elevation of 2428 meters above sea level.

*Ascodipteron* *euryale* sp. nov., ex. R. *stheno* – the top two images display the whole neosome. (Image credit: Haoran Sun et al.).

What makes Ascodipteron euryale stand out from its 17 known cousins? The most defining physical trait is the shape of its mesosternum, a part of its underside, which features gently rounded lobes on the back corners. Further, unlike many related flies that are covered in soft skin and easily removed, these neosomes were found encased in a fibrous cyst or shell – this is a reaction from the host bat’s own immune system, creating a protective barrier that makes the parasite very difficult to extract.

*Ascodipteron* *euryale* sp. nov., ex. R. *stheno*, head and thorax. (Image credit: Haoran Sun et al.).

The naming of the species is a clever nod to Greek mythology. The host bat, Rhinolophus stheno, shares a name with Stheno, one of the three Gorgon sisters who could turn onlookers to stone. The researchers decided to name the new fly euryale after Euryale, another of the Gorgon sisters. In the myths, these two sisters were immortal, and the authors note that this name choice reflects their hope that the deep-rooted biological association between this specific bat and its resident fly continues long into the future.

This research adds a sixth species of Ascodipteron to the records in China, emphasising the impressive biodiversity hidden within the country’s cave systems. It also raises new questions for future study, particularly regarding why some of these flies trigger the formation of fibrous shells while others do not. For now, Ascodipteron euryale remains a testament to the strange and highly specific ways life finds a niche (even if that niche is the inside of a bat’s ear)!

Original source:

Sun H, Ding L, Zhang D, Pape T (2026) Ascodipteron (Diptera, Nycteribiidae, streblid grade) from China: a new species from the lesser brown horseshoe bat, Rhinolophus stheno. ZooKeys 1273: 277-286. https://doi.org/10.3897/zookeys.1273.183551

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

Family of scaffold web spiders increased with ~20% following discovery of 43 new species

Recent study into spider specimens collected from across China, Indonesia, Philippines, Singapore, Thailand, Vietnam and Madagascar over the past 15 years, revealed the striking number of 43 scaffold web spiders that have stayed hidden from science until now. By describing the new species in a paper published in the open access journal ZooKeys, scientists from Sichuan University and the Chinese Academy of Sciences increase the number of a scaffold web spider family (Nesticidae), known from around the world, with about twenty percents.

The studied family of scaffold web spiders is a relatively small group of arachnids, which can be found at almost any locality, apart from Siberia, Central Asia, Northern and Southern Africa and places at high latitude. Prior to the study of Drs Yucheng Lin, Francesco Ballarin and Shuqiang Li, the species counted 245 in total, 12 of which are extinct and known from fossils only. A curious peculiarity in these spiders is their comb of serrated bristles, located on their rear legs, used to pull silk bands for their webs.

Although large-scale taxonomic surveys of scaffold web spiders have long remained scarce, recently the interest towards spider research in China and Southeast Asia has seen a significant rise. Thus, over the last 15 years, Chinese, American and European arachnologists have carried out several surveys, ending up with precious samples. As a result, Dr Yucheng Lin and his team followed with deeper morphological and molecular studies to discover remarkable diversity.

In their work, the researchers have also established a new genus (Speleoticus) for five previously known, but misplaced species, which spend a lot of their time taking shelter in caves.

The majority of scaffold web spiders occur in temperate areas of the Holarctic realm, where the species tend to be medium-sized, long-legged, and prefer cave-like environments. The species found in the tropical and subtropical areas are, on the other hand, usually smaller, with shorter legs, and can be quite often spotted outside, where they crawl in forest litter, on grass, and under stones.

Original source:

Lin Y, Ballarin F, Li S (2016) A survey of the spider family Nesticidae (Arachnida, Araneae) in Asia and Madagascar, with the description of forty-three new species. ZooKeys 627: 1-168. https://doi.org/10.3897/zookeys.627.8629