Bats are nocturnal mammals that are critical to healthy ecosystems around the globe; they act as pollinators, seed dispersers, and natural pest controllers. In honour of Bat Appreciation Day (17 April), we are highlighting some of the most interesting bats published in our open-access journal ZooKeys.
The following discoveries, ranging from a species rediscovered after a century to new regional records, emphasise the remarkable diversity of bats and the ongoing efforts of researchers to understand and protect them.
The Strange Big-eared Brown Bat (Histiotus alienus)

For over a hundred years, the strange big-eared brown bat was known only from a single specimen collected in Uruguay in 1916. This elusive species remained unseen by the scientific community for a century, leading to significant uncertainty regarding its biology and true distribution.
However, a study led by Brazilian researchers documents the rediscovery of this bat in the Palmas Grasslands of southern Brazil, providing the first confirmed record for the country. This finding significantly expands the known range of the species and offers researchers the first opportunity to provide a detailed redescription.
Histiotus alienus is distinguished by its large and oval ears that are connected by a low skin fold. Its fur is a deep, dark brown on the back, while the underside is slightly paler. The rediscovery occurred in a unique landscape characterised by high-altitude grasslands and Araucaria forests, a habitat that is increasingly threatened by human activity.
Learn more: Cláudio VC, Almeida B, Novaes RLM, Navarro MA, Tiepolo LM, Moratelli R (2023) Rediscovery of Histiotus alienus Thomas, 1916 a century after its description (Chiroptera, Vespertilionidae): distribution extension and redescription. ZooKeys 1174: 273-287. https://doi.org/10.3897/zookeys.1174.108553
The Flat-skulled Woolly Bat (Kerivoula depressa)

The world of bat taxonomy is constantly shifting as researchers use new tools to differentiate species that look nearly identical. Another study formally documents the first records of the flat-skulled woolly bat, Kerivoula depressa, in China.
Previously, many woolly bats in the region were grouped together under other names, but detailed morphological and genetic analysis confirmed that K. depressa is a distinct part of the Chinese fauna, specifically in Guangdong and Yunnan provinces.
The defining feature of this species is its notably flattened braincase. This physical trait is an evolutionary adaptation that allows the bat to roost in very narrow spaces, such as the hollow internodes of bamboo. The bat has woolly fur that ranges from buff brown to dark brown, and it is relatively small in size.
The presence of this specialist bat in China highlights the complexity of tropical forest ecosystems and the need for further taxonomic work to correctly identify and conserve local biodiversity.
Learn more: Liang X, Xie H, Li Y, Huang Z, Li S, Wu Y, Yu W (2023) First record of the flat-skulled woolly bat Kerivoula depressa and the Indochinese woolly bat K. dongduongana (Chiroptera, Vespertilionidae) in China. ZooKeys 1149: 1-15. https://doi.org/10.3897/zookeys.1149.85821
The Lesser False Vampire Bat (Megaderma spasma)

Islands often host a high number of unique species, yet their mammalian populations are frequently understudied. A comprehensive survey on Ko Pha-ngan, an island off the coast of Thailand, identifies the lesser false vampire bat, Megaderma spasma, as a new record for the island.
This species is a member of a group known for their distinctive appearance and predatory habits. While its name might sound ominous, it does not feed on blood; instead, it preys on insects and occasionally small vertebrates.
The lesser false vampire bat is easily recognised by its exceptionally large ears that are joined at the base and the absence of a visible external tail. During the survey, researchers found this species in a variety of environments, including national park forests, disturbed forest fragments, and areas with human settlements.
The discovery of M. spasma and eighteen other new records on Ko Pha-ngan demonstrates the importance of conducting biodiversity surveys in tourist-heavy regions to inform better conservation policies.
Learn more: Cook-Price DR, Petko ON, Makchai S, Artchawakom T, Suwanwaree P (2025) Mammal diversity survey of Ko Pha-ngan in Surat Thani Province, Thailand. ZooKeys 1229: 77-102. https://doi.org/10.3897/zookeys.1229.118127
The Grey-bellied Dwarf Dog-faced Bat (Molossops griseiventer)

Some species remain hidden until scientists take a closer look at existing museum collections and genetic data. For years, the grey-bellied dwarf dog-faced bat was considered a synonym of the more common Molossops temminckii. However, a recent revision has revalidated Molossops griseiventer as a separate species.
This grey-bellied dwarf dog-faced bat can be identified by its characteristic greyish ventral fur and specific cranial proportions. Beyond its appearance, the revalidation of this species has major implications for its protection. Unlike its more widespread relatives, M. griseiventer is restricted to the inter-Andean valleys of Colombia, a region heavily impacted by agricultural development.
Because it is now recognised as an endangered species, conservationists can advocate for specific protections for its remaining habitat. This case proves that understanding the true diversity of bats is a prerequisite for effective conservation.
Learn more: Ramírez-Chaves HE, Morales-Martínez DM, Martínez-Medina D, Ossa-López PA, Rivera-Páez FA (2023) Revising the diversity within the Dwarf Dog-faced Bat, Molossops temminckii (Chiroptera, Molossidae), with the revalidation of the endangered Molossops griseiventer. ZooKeys 1180: 237-256. https://doi.org/10.3897/zookeys.1180.109091
The stories of these four species remind us that our understanding of biodiversity is always evolving. Through continued exploration and open-access publishing, we can better appreciate and protect the bats that share our planet.
Once again, Happy Bat Appreciation Day from ZooKeys and Pensoft Publishers!
For more articles on zoology, visit the ZooKeys website and follow the journal on BlueSky and Facebook.































