Paedophryne dekot—dekot means "very small" in the local Daga language—is about 8.5 to 9 millimeters long. The bumpy-skinned P. verrucosa, meaning "full of warts" in Latin, is an average of 8.8 to 9.3 millimeters in length.

The previous tiny titleholders, also frogs in the Paedophyrne genus, were about ten millimeters long.

Not only are the new found frogs the smallest known in the world, they're also the smallest tetrapods, or vertebrates with four legs. The planet's tiniest known vertebrate is the Southeast Asian fish species Paedocypris progenetica, with mature females measuring just 7.9 millimeters.

"I'm always amazed by the size of these small frogs you find—it's really pushing the limit of what's possible," said Robin Moore, an  amphibian expert with Conservation International who was not involved in the study.

Scientists located the teensy creatures by listening for their calls and trying to zero in on the sources of the sounds.