Frog with tapir-like nose found in Amazon rainforest, thanks to its 'beeping' call

The people of Peru’s ​​Comunidad Nativa Tres Esquinas have long known about a tiny, burrowing frog with a long snout; one local name for it is rana danta, “tapir frog” for its resemblance to the large-nosed Amazonian mammal. But until now, this frog has remained elusive to biologists. Thanks to the help of local guides, an international team of researchers was able to find the frog and give it an official scientific name and description.

“These frogs are really hard to find, and that leads to them being understudied,” says Michelle Thompson, a researcher in the Keller Science Action Center at Chicago’s Field Museum and one of the authors of a study describing the frog in Evolutionary Systematics. “It’s an example of the Amazon’s hidden diversity, and it's important to document it to understand how important the ecosystem functions.”

“Frogs of this genus are spread throughout the Amazon, but since they live underground and can’t get very far by digging, the ranges each species is distributed in are fairly small. Since we found this new species in Amazon peatland, it wouldn’t be strange for it to be restricted to this environment. Its body shape and general look seems to be adapted to the soft soil of the peatland, rather than the robust and wider shape of species in other environments,”says Germán Chávez, a researcher at Peru’s Instituto Peruano de Herpetología and the study’s first author.

The tapir frog’s appearance is striking. “It looks like a caricature of a tapir, because it has a big blobby body with this tiny little pointy head,” says Thompson. But despite its goofy appearance, it was very difficult to find. “The frogs are tiny, about the size of a quarter, they're like brown, they're underground, and they're quick,” she says. “You know these little frogs are somewhere underground, but you just don’t see them hopping around.”

But while the frogs are hard to see, they're not hard to hear. “We just kept hearing this beep-beep-beep coming from underground, and we suspected it could be a new species of burrowing frog because there had recently been other species in its genus described,” says Thompson. “But how do we get to it?”

Local guides who were familiar with the frogs led the researchers to peatland areas-- wetlands carpeted with nutrient-rich turf made of decaying plant matter. The team searched by night, when the frogs were most active.

“We had already caught a juvenile our first night in the peatlands, but at 2-3am, we were tired. So, we chose our last night in that site, after three hard nights searching for frogs and snakes, to go to the peatlands exclusively to find those frogs that we heard the first night,” recalls Chávez.  “David Sánchez, one of our coauthors from the Instituto Amazónico de Investigaciones Científicas in Colombia, suggested that once we heard one of these lads calling, we create an imaginary square, perhaps one meter by one meter, and started to dig with our hands in this square to find them.”

“We could hear them underground, going beep-beep-beep, and we’d stop, turn off our lights, and dig around, and then listen for it again,” says Thompson. “After a few hours, one hopped out of his little burrow, and we were screaming, ‘Somebody grab it!’”

“After 15 to 20 minutes of digging and looking for them, I heard Michelle screaming, and to me that could only mean that she and David had found the first adult,” says Chavez.

In addition to finally finding adult specimens of the frogs, the team recorded their calls. “I am obsessed with recording frog calls, so I decided to record the call first and then continue digging,” says Chávez.

The researchers used the physical specimens of the frogs, along with the recordings of their calls and an analysis of the frogs’ DNA, to confirm that they were a new species. They named them Synapturanus danta-- Synapturanus is the name of the genus they belong to, and danta is Spanish for “tapir.”

“Our genetic analyses show this new species belongs to a group that evolved in the western Amazon, where the influence of prehistoric landscapes like the Pebas Lake might have created different wetlands, which originated the diversity we see in Synapturanus today,” says Chávez.

The frogs’ burrowing behavior that made them hard to find likely makes them an important part of their peatland home. “They're part of the underground ecosystem,” says Thompson. “They're moving down there, they’re eating down there, they're laying their eggs down there. They contribute to nutrient cycling and changing the soil structure.”

“Beside the important role of this new species in the food chain of its habitat, we believe that it could be an indicator of healthy peatlands,” says Chávez. “First, we have to confirm whether it’s restricted to this habitat, but its body adaptations seem to point in that direction. For instance, if the habitat is too dry, the soil would become too hard for a non-robust frog like this one to dig. This would leave our frog with far fewer chances to find a shelter and eventually, it would be hunted by a bigger predator. So I think possibilities that this frog would be a wetlands specialist are high, but still need to go further in this research to confirm it.”

And the study’s implications go beyond the description of one little frog. S. danta was found during a rapid inventory led by Field Museum scientists, a program in which biologists and social scientists spend a few weeks in a patch of the Amazon to learn what species live there, how the people in the area manage the land, and how they can help make a case for the area to be protected. “Even though it's called a rapid inventory, it could take a year or more to plan these things, and then it could take a year or a decade to do the conservation follow-up,” says Thompson. “The rapid part is where you spend a month in the field. And it’s a total whirlwind.”

Rapid inventories rely upon local expertise, both of scientists and of the people who live on the land. “The most special thing about rapid inventories is the group of people you’re with,” says Thompson. “There are people sharing their traditional knowledge about the land that they're from, people from universities, museums, governments. Bringing all these people with different background together is probably the best space to learn in.”

Peru’s Putumayo Basin, where this rapid inventory took place, is part of a larger conservation scheme by the Keller Science Action Center and its partners. “The Putumayo Corridor spans from Ecuador, Colombia, Peru, and down to Brazil, following the Putumayo River,” says Thompson. “There's very little deforestation, and it’s also one of the last free flowing rivers that has no current dams. There's like a huge conservation opportunity to conserve the whole corridor, watershed and surrounding areas. This tapir frog is another piece of evidence of why scientists and local people need to work together to protect this region.”

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