A new-to-science night frog species, Nyctibatrachus kali, has been identified in the Kali river basin of Karnataka’s central Western Ghats. Also known as the Kali night frog, the species was identified using a combination of morphology, genetics and bioacoustics, establishing it as a distinct evolutionary lineage.
The Western Ghats, one of the world’s major biodiversity hotspots, are home to exceptionally high amphibian diversity. According to the study, 253 amphibian species are currently known from the region, nearly 94% of them endemic. Night frogs of the genus Nyctibatrachus are themselves endemic to the Western Ghats, and around 70% of these species have highly restricted distributions.
Like many Nyctibatrachus frogs, the Kali night frog is a cryptic species — one that closely resembles other species externally, but is genetically distinct.
Researchers encountered the frog during field surveys in 2021 in the Castlerock region of Uttara Kannada district, within the Kali river catchment.
“The discovery of the Kali night frog was a citizen-led effort in which forest department members also played a role,” says scientist K.V. Gururaja who was a part of the study. “Initially, the species was thought to be the already known Kumbara night frog (Nyctibatrachus kumbara), discovered in 2014. Researchers later collected DNA samples, recorded its calls and compared the findings, which showed that the frog was genetically and acoustically distinct.”
According to scientist and co-author Preeti Hebbar, frog discoveries in the past were largely based on morphology alone, but that approach is no longer sufficient. Advances in molecular biology and bioacoustics now allow scientists to identify species more accurately using three key parameters: subtle morphometric differences, genetic divergence and distinct acoustic calls. “Molecular and acoustic studies are bringing out cryptic diversity in the Western Ghats rainforests,” she says.
A major takeaway from the study is that hidden biodiversity may exist even in landscapes already affected by development. Researchers note that had the species not been identified in time, its habitat may not have been recognised as ecologically important, particularly amid concerns over railway expansion in the region.
“Now, the forest department can intervene with a better understanding of the biodiversity present there. Development and conservation should go hand in hand,” Hebbar says.
Banner image: A Kali night frog. Image by Aravind C.K.
