Scientists discover new horned frog species in Arunachal Pradesh mistakenly identified as Vietnamese reptile earlier

A forest-dwelling horned frog from Northeast India, previously misidentified as the Maoson horned frog (Xenophrys maosonensis), has been newly described as a distinct species.

This leaf-litter dwelling frog, known for living amongst tea leaves and sporting small horns, is dark brown in colour and has been identified as Xenophrys apatani.

Researchers from the Zoological Survey of India (ZSI) in Shillong and Pune, who identified the new species, said the discovery adds significantly to India’s herpetofaunal diversity.

The study, led by Bhaskar Saikia and Bikramjit Sinha of ZSI, Shillong, also involved KP Dinesh and A Shabnam from ZSI, Pune and Ilona Jacinta Kharkongor from ZSI, Itanagar.

The newly discovered horned frog bears a strong resemblance to the Maoson’s horned frog, which has a wide distribution in Vietnam and China.

The megophyrid genus Xenophrys has been divided into ten subgenera, and  Xenophrys sensu stricto is known to include 28 valid species worldwide, 16 of which are found in India.

The new species was first reported from Arunachal Pradesh in 2019. However, researchers mistakenly overlooked the significant geographical barrier of 1,600 kilometres separating Vietnam and Arunachal Pradesh.

Furthermore, genetic analysis was not conducted at the time. This prompted the researchers to delve deeper to identify the species and its unique characteristics. They found that the frog species in Arunachal Pradesh exhibited a genetic disparity of 4.4 per cent to 5.5 per cent compared to its counterpart in Vietnam.

KP Dinesh, a scientist at ZSI in Pune, explained that, in addition to morphological analysis, integrated methods are now being used to help identify similar species, particularly those belonging to the same family.

“There’s no set rule regarding the level of genetic diversity required for each species,” he said. “However, geographical distance and a 1 per cent genetic divergence can also warrant further examination to determine if a new species is present.”

Dinesh added the species, now found in the Tale Wildlife Sanctuary in Arunachal Pradesh, India, has been named after the Apatani tribe. The Apatani people predominantly reside in the Lower Subansiri Valley of Arunachal Pradesh (where the Tale Wildlife Sanctuary is located). The naming of the new species is a recognition of their ingenuity in conserving wild flora and fauna.

“Since we now know this species is endemic and not widely distributed, further studies are needed to understand its geographical range, population size, habitat requirements and other factors. However, its location within a protected area suggests it’s currently safe. Nevertheless, anthropogenic pressures should still be considered,” Dinesh concluded.

The study also provided insights into the biogeographic distribution of Xenophrys species in India, which are concentrated along the Eastern Himalayas and Indo-Burma biodiversity hotspots of the country.

Northeast India has seen a number of amphibian species discovered in recent decades and it’s likely that many undocumented species, particularly smaller Xenophrys ss species, are still waiting to be found, Dinesh noted.