Northeast India yields 13 newly described bush frog species

Thirteen new bush frog species have been identified in northeast India, in what researchers say is the region’s biggest amphibian discovery in over ten years.

Researchers from the Wildlife Institute of India (WII) in Dehradun said that of the 13 species belonging to the genus Raorchestes, six were found in Arunachal Pradesh and three in Meghalaya. One species each was recorded in Assam, Mizoram, Nagaland and Manipur.

The findings, published in the journal Vertebrate Zoology, list the new species as Raorchestes orientalis (suggested common name: Eastern bush frog), Raorchestes mawsynramensis (suggested common name: Mawsynram bush frog), Raorchestes boulengeri (suggested common name:  Boulenger’s bush frog) and Raorchestes barakensis (suggested common name:  Barak Valley bush frog).

Others include Raorchestes narpuhensis (suggested common name: Narpuh bush frog), Raorchestes lawngtlaiensis ( suggested common name: Lawngtlai bush frog), Raorchestes nasuta (suggested common name: Pointy-nosed bush frog), Raorchestes dibangensis (suggested common name: Dibang Valley bush frog), Raorchestes monolithus (suggested common name: Willong-Khullen bush frog), Raorchestes khonoma (suggested common name: Khonoma bush frog), Raorchestes eaglenestensis (suggested common name: Eaglenest bush frog), Raorchestes arunachalensis (suggested common name: Arunachal bush frog) and Raorchestes magnus (suggested common name: Large bush frog).

The species were discovered between 2016 and 2024 from 204 specimens collected across 81 locations in eight northeastern states. All described species are endemic to the region.

The discovery brings the total number of Raorchestes species known from northeast India to 21. Across Asia, 212 species of bush or shrub frogs have been documented, 121 of which were described in the past two decades. The continent is home to three genera of bush frogs: Philautus, Pseudophilautus and Raorchestes.

The scientists said an “integrative approach” — comparing mitochondrial DNA divergence, a nuclear-encoded gene, and morphological and bioacoustic data — enabled them to confirm and describe the 13 new species. The paper noted that this is the first study to include the genus Raorchestes from the sub-Himalayan region, which had previously been the subject of anecdotal research.

Seven of the 13 species were found in protected areas in Arunachal Pradesh, Assam and Meghalaya, while one was located in a community-protected forest in Khonoma, Nagaland.

In Arunachal Pradesh, two species were identified in Namdapha Tiger Reserve and one each in Eaglenest Wildlife Sanctuary and Mehao Wildlife Sanctuary. Meghalaya’s three species include the Narpuh bush frog from Narpuh Wildlife Sanctuary, the Mawsynram bush frog from Mawsynram, and Boulenger’s bush frog, named after GA Boulenger, a British-era authority on amphibians. In Assam, the Barak Valley bush frog was described from Barail Wildlife Sanctuary.

Before this study, 82 species of bush frogs were known from India, 15 of which were recorded in the northeast.

The authors said the discoveries highlight “poorly explored biodiversity status” even within protected areas such as Tiger Reserves. Co-author Abhijit Das said the work forms part of a wider effort to understand “cryptic biodiversity” among northeast India’s bush frogs.

“We initially thought they would be hyper-diverse in the region, but the result was not. We ended up knowing the distribution of every species using multiple techniques, besides the description of 13 new [species],” he said.

The study, considered a significant step towards recognising the region’s hidden biodiversity, integrates acoustics, genetics and morphology.

“Now that we have defined species distribution in quite a few protected areas and know their call patterns, we can initiate acoustic monitoring to detect any future changes in population,” Das added.

The authors noted that the study addresses three major conservation shortfalls: the Linnean shortfall (naming species before they are lost), the Wallacean shortfall (understanding species distribution) and the Darwinian shortfall (providing evolutionary relationships).