New bat species and first records uncovered in the Western Himalayas

Based on years of field research and re-examining museum specimens, a team of bat biologists has published a taxonomic review of bat diversity in Uttarakhand and Himachal Pradesh. This revised inventory of bats from the Western Himalayas comprises 53 species in 24 genera and seven families, representing a remarkable 40% of the total 134 bat species known from India.

The review describes a new species, reports a previously unrecorded species from India, and documents new locality records of several species, thereby adding to our understanding of bat diversity in the region.

Bat taxonomy is undergoing an evolution, according to Uttam Saikia, one of the authors of the review and a bat researcher with the Zoological Society of India. “Traditionally, bat taxonomy and species delineation involved recording various morphological parameters of adult specimens, coupled with measurement of the cranium (skull) and dental characteristics,” Saikia said.

“However, with the advent of molecular tools like DNA barcoding and the availability of ancillary data such as echolocation call structure, taxonomists have taken an integrative approach, wherein all the relevant data are combined to make species distinctions more robust,” he said.

Published in the Zootaxa journal, this taxonomic review of bats from the Western Himalayas also adopts an “integrative approach”, combining morphology, molecular genetics, and acoustics.

The search for the long-tailed

The newly described bat species from Uttarakhand is the Himalayan long-tailed Myotis (Myotis himalaicus), which, as the name suggests, has a tail almost as long as its body. This species belongs to the Myotis frater complex, a group of morphologically similar bat species found across eastern and central Asia. Myotis is one of the largest and most cosmopolitan genera of bats, comprising more than 100 species worldwide.

“The first time I caught this bat was in 2016,” said Rohit Chakravarty, one of the authors of the review and a bat researcher and conservationist with the Nature Conservation Foundation. “Though it did seem different from the other bats I had caught, I didn’t have any suspicions [it was a novel species].”

Long after completing the fieldwork, while studying its DNA sequence, it emerged that there was a significant genetic divergence from other similar species within the Myotis frater complex. However, to confirm it as a new species, researchers needed a specimen to study the morphological and anatomical characteristics. It took Chakravarty and team five years to catch another specimen and “put all the pieces of the puzzle together.”

In 2021, when Chakravarty finally caught the bat, he knew immediately that his long search had come to an end. Over the years, handling different species of Myotis from the Himalayas, Chakravarty could tell the specimen was heavier (by 2-3 grams) than other Myotis found in the region, and it had a distinctive bare patch around the eye.

With a study specimen, they were able to establish its distinct taxonomic status as a novel species, according to Saikia. “As we investigated the specimen closely, we found a suite of morphological, cranial, dental, and baculum (a bone in the penis found in certain mammals) characteristics unique to the species,” he said.

Upon examining old museum specimens, the researchers came across a very similar specimen in a collection from the Hungarian Natural History Museum. It was an adult female collected by G. Csorba and L. Ronkay on July 22, 1998, in Khyber Pakhtunkhwa, Pakistan — about 700 km to the west of Uttarakhand.

Since both specimens were externally and cranially indistinguishable, and were caught from the same continuous montane forests in the Himalayas, the researchers concluded that both belong to the same species.

The unique biogeography of the Himalayas

The Himalayas are biogeographically very interesting, according to Chakravarty. They are relatively young mountains, formed from the collision of the Indian and Eurasian tectonic plates. They fall in the transition zone between the Oriental and Palearctic zoogeographic realms, and therefore shares faunal elements of both.

Until now, the free-tailed bat species recognised in India was the European free-tailed bat (Tadarida teniotis). But the recent discovery of the East Asian free-tailed bat (Tadarida insignis) in the Oriental region led the research team to question which of the two species is found in India.

“It got us thinking. India is right in the middle of these two places, what is the bat that we have here?” Chakravarty said.

Free-tailed bats fly very high above the ground, making them impossible to catch them. However, interestingly, free-tailed bats call at very low frequencies that fall within the audible range. The team was able to use a Bluetooth speaker to broadcast calls at their site in the Kedarnath Wildlife Sanctuary and successfully captured a specimen. Upon genetic examination, their hypothesis proved correct, and the team recorded the East Asian free-tailed bat for the first time in India.

Similarly, the research team delineated the Babu’s pipistrelle (Pipistrellus babu) from the Javan pipistrelle (Pipistrellus javanicus). Very similar, small bats, previously, they were thought to belong to the same species. “Considering the huge geographic distances between their type localities (locality from where the species were originally described), we examined specimens from the Himalayas and found distinct morphological and anatomical characters that convincingly separated the two species,” Saikia said.

The taxonomic review also detailed first occurrences of the Japanese greater horseshoe bat, Savi’s pipistrelle and Mandelli’s mouse-eared bat in the Western Himalayas for the first time.

The future of bat taxonomy

The Himalayan long-tailed Myotis highlights the Western Himalayas as an important centre of endemism, according to Chelmala Srinivasulu, Professor at the Department of Zoology, Osmania University, Hyderabad. “Species that appear similar morphologically are often genetically distinct due to isolation in complex terrain,” he said.

“We have only scratched the surface of bat diversity in the Western Himalayas,” Srinivasulu added. Chakravarty also agreed that bats remain an undiscovered group in the Himalayas, and there is so much more to discover.

“The Himalayas as a whole is an undersampled region in terms of bat diversity, and the priority should be extensive surveys for fresh specimen collection and analysis,” Saikia said.

However, field access and logistics in remote Himalayan regions continue to pose challenges, according to Srinivasulu. “Capacity building in terms of trained taxonomists, bio-acousticians, and molecular ecologists is still needed in many parts of India,” he said.

“In the next decade, India could become a global hotspot for chiropteran systematics and evolutionary ecology, provided adequate institutional and funding support is made available to bat researchers,” Srinivasulu concluded.

Read more: Automating bat detection for more efficient monitoring and data collection

Banner image: The East Asian free-tailed bat (Tadarida insignia) was recently recorded for the first time in India. Image by Rohit Chakravarty.