Deep inside the forests of Namdapha Tiger Reserve in Arunachal Pradesh, scientists have discovered a new species of “fanged frog” that builds mud nests under leaf litter—a rare behaviour shedding new light on amphibian diversity in Northeast India.
The species, described by researchers Bitupan Boruah, N.V. Rajiv, Sourav Dutta and Abhijit Das, has been named Limnonectes motijheel after a forest wetland inside the reserve.
Motijheel is a small wetland located within evergreen forests of Namdapha Tiger Reserve. It is a popular tourist trail and an exceptionally diverse amphibian habitat, supporting the breeding of at least 10 species.
A frog that nests in mud
Unlike most frogs that lay eggs in water, the newly described species shows a unique nesting strategy—constructing mud nests beneath leaf litter, from where males call.
“The new species exhibits a unique nesting behaviour, constructing mud nests under leaf litter,” the researchers note.
“If you go to Namdapha in April, or to Dehing Patkai in Assam—two hyper-diverse evergreen forests of the Northeast—you may hear a very unusual call coming from the dark, leaf-littered forest floor. But spotting the frog is not easy, as it calls from a self-crafted, subterranean mud nest to attract a mate,” said Abhijit Das.
Field observations suggest that locating these frogs is particularly challenging, as males call from concealed mud pits on the forest floor.
Hidden diversity in a biodiversity hotspot
Alongside the discovery, the study also reports the presence of another fanged frog—Limnonectes longchuanensis—from India for the first time.
While L. motijheel is new to science, L. longchuanensis is an already known species that had not previously been documented in the country. This brings the total number of Limnonectes species known from India to six.
The discovery was made during field surveys conducted between 2022 and 2023 in Namdapha, part of the Indo-Burma biodiversity hotspot, a region known for its exceptional but still underexplored biodiversity.
According to the study, the new species shows clear genetic and morphological differences from its closest relatives, confirming it as a distinct lineage. Currently, it appears to be restricted to Namdapha Tiger Reserve and nearby forest landscapes, though researchers suspect a wider distribution in adjoining areas.
Frogs are critical indicators of ecosystem health, especially in forest and freshwater systems. The discovery of a new species—along with a new national record—highlights how much of Northeast India’s biodiversity remains undocumented, particularly in leaf-litter and forest floor habitats that are often overlooked.
In the damp, leaf-covered ground of Namdapha, where even a small mud nest can hide an unknown species, the message is clear: Northeast India’s biodiversity is far from fully understood.
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