Newly discovered: smallest fanged frog in the world

A tiny fanged frog, about 2 centimetres long, has been hiding out in jungles on the Indonesian island of Sulawesi.

According to the team of US and Indonesian scientists that found it, it’s a species new to science – and the smallest known species of fanged frog.

They’ve published a description of the frog, dubbed Limnonectes phyllofolia, in PLOS One.

“This new species is tiny compared to other fanged frogs on the island where it was found, about the size of a quarter,” says lead author Dr Jeff Frederick, a postdoctoral researcher at the Field Museum in Chicago.

“Many frogs in this genus are giant, weighing up to two pounds. At the large end, this new species weighs about the same as a dime.”

The discovery was made on a joint expedition through Sulawesi with the Bogor Zoology Museum in Indonesia, and the University of California, Berkley, where Frederick did the research as a doctoral candidate.

“It’s a giant island with a vast network of mountains, volcanoes, lowland rainforest, and cloud forests up in the mountains. The presence of all these different habitats mean that the magnitude of biodiversity across many plants and animals is unreal – rivalling places like the Amazon,” says Frederick.

The researchers noted frog eggs on tree leaves and boulders. This is unusual, because frogs usually lay their eggs in water to keep them moist.

Frog eggs on leaf
The new species of frog’s eggs, laid on a leaf. Credit: Sean Reilly

“Normally when we’re looking for frogs, we’re scanning the margins of stream banks or wading through streams to spot them directly in the water,” says Frederick.

“After repeatedly monitoring the nests though, the team started to find attending frogs sitting on leaves hugging their little nests.”

The researchers found these guarding frogs had tiny fangs – and were all male.

“Male egg guarding behaviour isn’t totally unknown across all frogs, but it’s rather uncommon,” says Frederick.

The frogs belong to the genus Limnonectes, and the researchers have given them the species name phyllofolia because it means “leaf-nester”.

The researchers believe that the tiny fangs might once have been more frightening. Because these frogs have found a less competitive spot to keep their eggs – leaves rather than water – they lost an evolutionary pressure keeping the fangs big.

“It’s fascinating that on every subsequent expedition to Sulawesi, we’re still discovering new and diverse reproductive modes,” says Frederick.

“Our findings also underscore the importance of conserving these very special tropical habitats.”

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