At an average of 7.7 millimeters long, the newfound Paedophryne amauensis is a hair smaller than the previous record holder, the Southeast Asian fish species Paedocypris progenetica, whose females measure about 7.9 millimeters.

During recent field surveys in southern Papua New Guinea, scientists found P. amauensis and  another new species of tiny frog, Paedophryne swiftorum, which measures about 8.6 millimeters.

"I think it's amazing that they're continuing to find smaller and smaller frogs," said Robin Moore, an amphibian expert with Conservation International, who was not involved in the study.

(Related: "Smallest Frogs Found—Each Tinier Than an M&M.")

It's obvious "they're adapting to fill a niche that nothing else is filling," he said.

Indeed, the frogs likely evolved their tiny sizes to eat tiny invertebrates, such as mites, that are