The lush volcanic hills of Sulawesi, Indonesia, are home to several species of toothed frogs with unusual breeding habits. Limnonectes larvaepartus – It is the only frog species in the world known to give birth to live tadpoles. Now this tropical island has revealed more than one secret: the world’s smallest toothed frog. Relatedness to other recently discovered species of frog teeth Limnonectes filofolia It is the traditional egg laying of amphibians.

While traveling through a rainforest, a team of herpetologists from the United States and Indonesia came across leaves and moss-covered rocks a few feet above the ground containing the glassy eggs of a black frog. This immediately caught the attention of researchers, as frog eggs are almost always left in water to prevent the jelly coating from drying out.

Shortly thereafter, researchers spotted spotted, brown, coin-sized frogs defending their burrows.

“Typically, when we look for frogs, we scan stream banks or wade through streams to spot them in the water,” says lead author Jeff Frederick, a wildlife ecologist at the Field Museum in Chicago. “But after observing the nests repeatedly, the team began to find frogs sitting on leaves and cuddling up in their little nests.”

These guard frogs coat their eggs with compounds that keep them moist and free of bacteria and fungi. Interestingly, all of the frogs handling the eggs were males. “The male’s egg-protecting behavior is completely unknown to all frogs, but it is quite rare,” says Frederick.

This never-before-seen species of frog had a strip of tiny teeth on its upper jaw and two small canines protruding from its lower jaw. (Frogs generally have teeth only in their upper jaws.)

“This new species is very small compared to other dog frogs on the island where it was found,” says Frederick.

Other saber-toothed frogs in Sulawesi are two-pound giants, but this new species weighs only two grams, “about the size of a dime,” says Frederick.

The new species was named Limnonectes phyllofolia. (Phyllofolia means “nest leaf.”)

Various species of frogs in Southeast Asia have evolved teeth to fight for territory and mates and to hunt crunchy prey such as centipedes and crabs. Because tree frogs do not use waterways to reproduce, they do not need such large teeth to compete for the best spawning spots in a crowded stream.

The researchers suggested this might explain the small size of their canine teeth compared to other frogs on the island. Researchers have previously found that frog teeth evolved independently at least four times across all frog species.

Studies of the behavior and nutrition of these species have shown that frog teeth that develop in response to sexual selection appear relatively larger than those that develop in response to other environmental influences. Toothed frogs have been found in Cambodia, Vietnam, West Africa and South America. Scientists also discovered the tadpole teeth of the vampire flying frog (Rhacophorus Vampirus) in the evergreen forests of southern Vietnam.