Hundreds of Amazonian Frog Species Are Hiding in Plain Sight

The Amazon rainforest, particularly in Ecuador, is suspected to have the greatest biodiversity of species in the world. But its riches still aren't fully understood and, in the case of amphibians, the Amazon may have as many as five times as many species as previously suspected.

That's due to many of them being cryptic species, a term used to describe two or more similar-looking species that are mistakenly identified as one by scientists. It happens in all sorts of life forms—late last year, one species of jungle cat in Brazil was split into two after closer inspection.

In a new paper published in ZooKeys, Ecuadorian researchers discovered that two widespread species of tree frog, previously known as Hypsiboas fasciatus and Hypsiboas calcaratus, could actually be split into as many as 11 different species. For the time being, Santiago Ron of Ecuador's Museum of Zoology and his colleague Marcel Caminer were able to identify at least four new species of frog based on new genetic sequencing, second looks at morphology, and recordings of their mating calls.

"We examined the collection of frogs we have in our museum, sequences all the tissues we had available for the old two species, and it turns out, there are as many as 11 species," Ron said.

Though species that are sussed out via genetics alone are called cryptic species, Ron says that once genetic differences are identified, often physical ones can be discovered too.

"You can often go back to the specimens and examine them, and you'll find some morphological differences that were not obvious before," he said. "But it's true that some of them can only be identified by their genetics or advertising calls."

Overall, it's good news for frogs in general that there is so much genetic diversity within the Amazon. As a group, they are better suited to survive widespread disease, because they are less likely to jump between species.

But that makes each species—which have smaller rangers and likely lower populations than previously thought—more fragile to things such as habitat destruction, a particularly pressing problem in Ecuador considering that the country is already drilling for oil in the Amazon and is pressing forward with a plan to drill in the world's most biodiverse area. At the moment, Ron says there's no reason to suspect that any of the newly-discovered species are in danger, and frog populations in the Amazon have remained relatively stable over the past several years.

Ron's team is currently working on a catalog of all of Ecuador's frogs, a monumental task considering that previous estimates have suggested that there are as many as 580 species of frogs in a small area of eastern Ecuador's Yasuni National Park alone.

Add in highland frogs that live in the Andes mountains, species that live in other parts of the Amazon, and the news that there may be as many as five times as many cryptic species hiding in plain sight, and it's clear Ron has his work cut out for him. To start, Ron is doing a similar study with two other species of frogs. He suspects he'll find that those species, too, will have to be split into many.

"We think it's essential to describe the diversity we have here. This basic information is crucial to do serious science," he said. "You cannot conserve or protect something that you don't even know exists."