World’s Smallest Fanged Frog Is A Brand-New Species With Surprising Egg-Guarding Behavior

The new species weighs roughly the same as a dime.


Eleanor Higgs


Eleanor Higgs

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Eleanor is a content creator and social media assistant with an undergraduate degree in zoology and a master’s degree in wildlife documentary production.

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Limnonectes phyllofolia sat on brown leaves. Small green and brown frog. No visible fangs.

The call of this new frog species is a rapid series of clicks – this helped researchers tell it apart from other known species. 

Image credit: Sean Reilly

Frogs might be famous for a lot of things – croaking, ending up where they shouldn’t, and even confusing the internet – but their teeth are not one of them. Most frog species barely even have them. There is a group of around 70 species, however, which has fangs. Hopping around Southeast Asia, they use their chompers to fight other frogs and even to help get their jaws around their crab and giant centipede prey. Now, scientists have found one more fanged frog species, and it just might be the smallest in the world. 

“This new species is tiny compared to other fanged frogs on the island where it was found, about the size of a quarter,” said Jeff Frederick, a postdoctoral researcher at the Field Museum in Chicago and the study’s lead author, who conducted the research as a doctoral candidate at the University of California, Berkeley, in a statement sent to IFLScience. 


“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 new species also measures around 3 centimeters (1.18 inches) in body length, making it the smallest adult body size of any of the fanged frog species on the island where it was discovered.

The frogs were found at three spots on the island of Sulawesi in Indonesia, and it was their eggs that gave them away. This species lays its eggs on the sides of leaves and moss boulders, and so was given the name Limnonectes phyllofolia, with “phyllofolia" derived from the Greek works for "leaf" and "nest".

After a while, the team began to see the little frogs alongside the eggs. “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,” Frederick explained. “After repeatedly monitoring the nests though, the team started to find attending frogs sitting on leaves hugging their little nests.”

On closer inspection, the team found that all the frogs that were guarding the eggs, laid 1-2 meters (3-6 feet) above small streams, steeps, and trickles, were all male. “Male egg guarding behavior isn’t totally unknown across all frogs, but it’s rather uncommon," said Frederick.

Small black and grey frog eggs on a bright green leaf in a cluster.
Males guard the 5-millimeter round eggs before they hatch, after which tadpoles fall into the streams and seeps below.
Image credit: Sean Reilly

In their paper, the team expresses confidence that the frog is a new species due to some key characteristics, including the egg-guarding behavior and small body size. In addition to these, the frogs make an advertisement call that is unique to the species. The most similar species, L. arathooni, has a call featuring high-pitched chirps, while the new species' call consists of a rapid series of clicks. L. phyllofolia also has reduced webbing compared to other species in the genus.

The team also suggests that as well as this newly described species, there are potentially many more species of frogs present on the island of Sulawesi that have yet to be officially named to science. They propose that more fieldwork is needed to fully identify all these species and help conserve the habitats they live within.

“Our findings also underscore the importance of conserving these very special tropical habitats. Most of the animals that live in places like Sulawesi are quite unique, and habitat destruction is an ever looming conservation issue for preserving the hyper diversity of species we find there. Learning about animals like these frogs that are found nowhere else on Earth helps make the case for protecting these valuable ecosystems,” concluded Frederick.

The study is published in PLOS ONE.


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