Fanged frogs are members of Limnonectes, a large genus of frogs that includes at least 75 scientifically recognized species.

They are distributed from India to China and Indochina, through the Thai-Malaysia Peninsula, and across the Sunda Shelf landmasses (Borneo, Sumatra, and Java), the Malukus, the Lesser Sunda island chain, parts of western New Guinea, and the Philippines.

Genetic samples of the new species, the Mindoro fanged frog (Limnonectes beloncioi), were collected several years ago on Mindoro Island in the central Philippines but weren’t analyzed until recently.

Because of its nearly identical physical similarity to a fanged frog on the island of Palawan, called the Acanth’s fanged frog (Limnonectes acanthi), it was assumed to be the same species.

However, because the fanged frogs inhabit islands separated by miles and miles of ocean, University of Kansas doctoral student Mark Herr and colleagues had doubts they were the same species, in part because they had different-sounding calls.

The researchers decided to analyze the frogs’ genome and determined the Mindoro fanged frog qualified as its own distinct species. “This is what we call a cryptic species because it was hiding in plain sight in front of biologists, for many, many years,” Herr said.

“We also found differences in their mating calls. They sound quite different. So, it was a case of using acoustics to determine that the species was different, as well as the new genetic information.”

“The frogs’ fangs likely are used in combat for access to prime mating sites and to protect themselves from predators,” he added.

The Luzon fanged frog [Limnonectes macrocephalus] is a medium-sized frog endemic to the Philippines. While the function of the “fangs” [not teeth but rather jaw protrusions] is not currently known, it’s possible that they use them to help catch prey in fast-moving water, as they have been observed feeding on fish and tadpoles. The Luzon fanged frog is not the only species of frog found to have this trait; during a 2011 expedition to Sulawesi scientists encountered 13 different “fanged frogs”, 9 of which are believed to be new to science. 

1.5-2 inches fanged frog gives birth to tadpoles without laying eggs

NEW YORK: In the depths of an Indonesian rainforest, scientists have identified a fanged amphibian that is the first known frog that gives birth to tadpoles, instead of laying spawn. The newly named frog was found in small puddles and side streams in a rainforest in Sulawesi Island in Indonesia. It’s a small animal, about 1.5 to 2 inches long. In a paper in PLOS One describing the tadpole-bearing…

(fNationalGeographic)  Fanged-Frog: 9 New Species Found

Sulawesi fanged frog species (pictured, a new species, tentatively namedLimnonectes species I) also vary widely in terms of size.