Australia's Well-Known Noisy Frog Is Actually 3 Different Species: Study

What was believed to be a single frog species has turned out to be three different ones! The surprising discovery was made after researchers found two new species of the "loudest frog in Australia."

The Bleating Tree Frog (Litoria dentata) is quite well-known in Australia because of the "extremely loud, piercing calls" of the males, said the researchers of a new study, published in Zootaxa. The species is widespread, with its "broad latitudinal distribution" encompassing some biogeographic boundaries.

However, it appears that there may be more to these noisy frogs than previously thought.

"A recent mitochondrial DNA analysis showed a deep phylogeographic break between populations of L. dentata on the mid-north coast of New South Wales," the researchers wrote.

For their work, the researchers conducted a "more geographically comprehensive mitochondrial phylogeographic analysis." They also analyzed the submissions made to the FrogID project, a citizen science project where members of the public can submit recorded frog calls, the University of Newcastle noted in a news release.

The team found that even though they look and sound quite similar, there are actually three species of these loud frogs and not one. They include the L. dentata, which is apparently "restricted" to coastal north-eastern New South Wales; the Litoria balatus (Slender Bleating Tree Frog) in south-eastern Queensland and the Litoria quiritatus (Screaming Tree Frog) from north-eastern Victoria.

This brings the number of Australia's native frog species to 246.

"Our examination revealed that their calls differ slightly in how long, how high-pitched and how rapid-fire they are," Dr. Jodi Rowley, the lead scientist of the FrogID project, said, as per the university news release. "The Slender Bleating Tree Frog has the shortest, most rapid-fire and highest pitched calls."

The species also slightly varied in appearance, the university noted, with the Slender Beating Tree Frog being a bit more slender with a "distinctly black" vocal sac, while the Screaming Tree Frog isn't quite as slender and has a bright yellow vocal sac. The Robust Bleating Tree Frog, on the other hand, looks fairly similar to the Screaming Tree Frog but has a "brownish" vocal sac that turns yellow when inflated.

"Although similar in appearance, and in their piercing calls, the frogs are genetically very different. I'm still amazed that it's taken us so long to discover that the loudest frog in Australia is not one but three species," Professor Steven Donnellan, of the South Australian Museum, noted in the news release. "How many more undescribed species in the 'quiet achiever' category are awaiting their scientific debut?"

The work also highlights the value of citizen science in helping conserve the frogs, Rowley said. "Almost all" of the more than 240 frog species in Australia cannot be found elsewhere in the world, according to the FrogID project. While some of them are thriving, some have declined since the 1980s and four have even gone extinct.

"By recording a frog call with the FrogID app, you provide a unique, time-stamped and geo-referenced audio recording that allows scientists to understand and conserve Australia's unique frog species," the project noted.