Mantidactylus augustini frog in Madagascar.

The small brown frogs make delightful calls.

The newest frogs discovered in Madagascar have distinctive calls. They typically sound like a squeaky door or a hungry stomach.

Twenty frog species were recently named and cataloged by an international team of researchers. The small brown frogs are found throughout Madagascar’s forests, but they are difficult to spot. They belong to Mantidactylus Brygoomantis, which until now contained only 14 species.1

“This group of frogs are basically ubiquitous along streams in humid areas of Madagascar. They are shy and inconspicuous, and they emit these delightful creaking or gurgling calls that can make for a totally unique soundscape,” lead author, Mark D. Scherz, curator of herpetology at the Natural History Museum of Denmark, tells Treehugger.

“I always found this enchanting. It also makes them quite difficult to study, because we want to record that quiet call, but finding the individual emitting it can be quite challenging and requires both a lot of patience and a good eye.”

It took years of searching to find the species and catalog them. 

Scherz points out that the first work on frogs in this group was in the 1880s when the first was named. But most of the data comes from museum specimens collected over the past three decades. When researchers first started studying Madagascar’s amphibians and reptiles, they realized that most species from this group had never been scientifically described.2

Researchers began working with museomics, a process where they sequenced DNA from archived material in museums instead of just using fresh tissue. This helped them identify older specimens.2

“At that point, we reached a critical mass of data: We had genetic data from over 1,300 frogs, museomic data from critical specimens, call recordings from dozens of animals in the wild, and measurements from several hundred specimens,” Scherz says.

“Finally, we were able to initiate this massive effort, and pull all of this together to result in this monograph, and describe the 20 new species that all this work had revealed.”

The findings were published in the journal Megataxa.

Bringing Data Together

Researchers say this study showcases modern integrative taxonomy, which is classification that uses many sources of data to identify and describe new species. They used measurements and comparative anatomy, as well as bioacoustics where they analyzed frog calls. They also relied on basic DNA sequencing as well as sequencing from museum specimens and other ways of sequencing genetic markers.2

“Bringing all this data together was no small effort, and took a large team, but ultimately it coalesced to 35 species of Brygoomantis, 20 of which were identified as new, and named,” Scherz says.

So many “new” species are already threatened or endangered where they are discovered. This can be disheartening for researchers but makes their findings even more critical.2

“We are constantly losing species that nobody has ever collected and deposited a representative of in a natural history museum, our archives of knowledge of life on Earth,” Scherz says. “Whole tracts of habitats, especially forests, are often clear-cut for development or other reasons, and with them may vanish untold species. Decline and eventual extinction of species is a rule in evolution, but the rates at which this is happening, and our role in it, is devastating.”

Before researchers can understand the threats a species faces, they first need to collect data and name that species. The species requires a name before it can go on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species or before the trade of that species can be regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).2

“Habitats may be protected based on their diversity or presence of particular species.,” Scherz says. “So, describing species like these new frogs is a first step that both establishes our baseline knowledge of how they may be faring and enables their protection on multiple levels.”

Fact checked by Haley Mast