NEW DELHI: Researchers have discovered a new cascade frog and named it after the Adi hills, which are home to Adi tribes, an indigenous group of people from Himalayan regions in the Indian state of Arunachal Pradesh.

The team of Indian and American biologists from the Wildlife Institute of India, University of Delhi (India), and North Carolina Museum of Natural Science (USA) has discovered a new species of Cascade Frog from the Adi hills, India. Historically, this region was also known as Abor Hills.

The discovery was made when biologists were investigating a group of medium to large-sized Cascade Frogs (scientifically belonging to genus Amolops) from Northeast India over the last five years.

“Cascade Frogs” is named so because of their preference for small waterfalls or cascades in flowing hill streams. The genus Amolops is one of the largest groups of ranid frogs (family Ranidae) with currently 73 known species that are widely distributed across Northeast and North India, Nepal, Bhutan, China, through Indochina, to the Malaya Peninsula.

The new species was identified based on multiple criteria, such as external morphology, DNA, and calling pattern. The study also resolved century-old taxonomic confusions surrounding the identity of another cascade frog species, Amolops monticola, which was described from the Sikkim Himalayas 150 years ago.

These discoveries have important implications on the taxonomy and geographical distribution of several other members of this group found in India and the neighbouring regions of China. The findings are published in a scientific article titled ‘Phylogenetic position of the poorly known montane cascade frog Amolops monticola (Ranidae) and description of a new closely related species from Northeast India” in the Journal of Natural History, London. The full publication is available at: https://doi.org/10.1080/00222933.2021.1946185

“This study is once again testament to how little is known about the most threatened animal groups, frogs, in northeastern India. Many frogs in this region are reported to occur widely but have relatively small geographical ranges and require special attention for conservation before they go extinct forever. Northeast India is a treasure house of species still unknown to Science”, said professor S D Biju of the University of Delhi, the corresponding author of the article.

“The new species was discovered while revisiting century-old Adi expedition in the year 2018 and named after the land of Adi tribe in Arunachal Pradesh where this species dwells particularly during the post-monsoon season,” said Abhijit Das, from Wildlife Institute of India, Dehradun.