Researchers have discovered a new species of cascade frog from Arunachal Pradesh and named it after the Adi hills, the abode of Adi tribes. Amolops adicola , the new species discovered by a team of Indian and American biologists from the Wildlife Institute of India (WII), University of Delhi, India, and the North Carolina Museum of Natural Science, the U.S., is a predominantly brown colour frog, with a size ranging roughly between 4 cm to 7 cm. Cascade frogs are named so because of their preference for small waterfalls or cascades in flowing hill streams, for which they have developed certain morphological features such as expanded digit tips and extensive foot webbing that makes them adapt to strong water currents.
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.
“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, in fact, have relatively small geographical ranges and require special attention for conservation before they go extinct forever,” said S. D. Biju, University of Delhi, corresponding author of the study. “Northeast India is a treasure house of species still unknown to science.”
The species draws its nomenclature from Adi tribes, an indigenous group of people from the Himalayan regions of Arunachal Pradesh. The region from where the discovery was made is also referred as Adi hills — adi literally means “hill” or “mountain top”. Historically, this region was also known as Abor hills.
“The new species was discovered while revisiting a century-old Adi expedition in 2018, and named after the land of the Adi tribe in Arunachal Pradesh, where this species dwells particularly during the post-monsoon season,” said Dr. Abhijit Das, WII.
The details of the discovery can be accessed in the publication titled ‘Phylogenetic position of the poorly known montane cascade frog Amolops monticola (Ranidae) and description of a new closely related species from Northeast India’ published in the Journal of Natural History .
“The new species, formally described as Amolops adicolasp.nov., is morphologically distinguished from its congeners by a suite of characters that include adult size, body colouration and markings, skin texture, snout shape, foot webbing and digit tip morphology,” the publication reads. Apart from the external morphology, Amolops adicola was identified based on DNA and a distinct 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. 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.
