As Raffael Ernst stood in the dripping Amazon rainforest, he heard an unusual sound. It was an amphibian call but unlike any he had heard before. The German herpetologist dropped to his knees and began digging with his hands in the wet soil.
Soon, he was covered in mud, but he found his quarry: a new species he named “zombie frog,” reports Isabela Martel for Deutsche Welle. The tiny, orange-spotted specimen—measuring only 1.5 inches—was unusual looking, but will probably not be cast in The Walking Dead anytime soon.
The frog doesn’t get its name from its own characteristics. Instead, Ernst and his colleagues chose the evocative descriptor based solely on how they looked after pawing through the mud to find it.
“Actually, we chose this name because the researchers are the ones that look like zombies when they dig out the frogs from the ground,” he tells Deutsche Welle.
Ernst discovered the zombie frog, part of the genus Synapturanus, while doing field work for his Ph.D, studies in Guyana, South America. He has since joined efforts with other researchers from Senckenberg Research Institute in Germany and the National Museum of Natural History in London to continue searching the tropical rainforest of the Guiana Shield, which covers Guyana, French Guyana and Brazil.
In a paper published this month in the journal Zoologischer Anzeiger, the team identified two other species in the same genus, Synapturanus mesomorphus and Synapturanus ajuricaba, describing them as “fossorial Amazonian frogs.” In this remote region of the Amazon jungle, “there may be six times more species than currently recognized,” according to the study.
Little is known about the zombie frog and its cousins. They are rather plump with narrow mouths and pointed noses. The small, nocturnal amphibians of the genus Synapturanus live mostly underground. Males only emit their calls during or just after the heavy rains in the tropical setting, making it extremely challenging to pinpoint their locations.
“Until now, little scientific attention has been paid to this genus,” Ernst says in a statement. “The frogs’ habitats are difficult to access, and their ranges are very small; moreover, the animals hide underground and their calls are rather difficult to differentiate.”
While excited by the discovery, Ernst is realistic about what is happening to amphibians around the world and the danger that poses to zombie frogs, reports Zaina Alibhai of i newspaper, a digital publication in the United Kingdom. Amphibians are considered a bellwether species that can indicate environmental problems, but around 70 percent are threatened with extinction.
“Whenever we discover new species, we always have in mind that we are losing species at the same time, probably more than we discover, and before we even have the chance to describe them,” Ernst says.
Though one of the most biodiverse places on the planet, the Amazon rainforest is under immense pressure from industrial interests, including mining, timber extraction, logging, poaching and large-scale infrastructure projects. Ernst tells Deutsche Welle that amphibians in particular are extremely sensitive to water quality, habitat destruction, disease and more.
“The threats are multiple and on top of that, we have climate change problems as well,” he says.
Brazil is one area where amphibians are threatened. The country has been clearing rainforest at a record rate over the past decade. In 2020, nearly 7,000 square miles were deforested, according to a study published in the online journal Nature Ecology & Evolution. In May of this year, 455 square miles of Amazon rainforest were cleared in Brazil.
Ernst is concerned about the fate of the zombie frog and its cousins. He fears these delicate species may not be able to hold out for long against this continual onslaught of threats by humans.
“We are losing biodiversity at an unprecedented rate, and the current administration in Brazil has unfortunately been a disaster for that,” he tells Deutsche Welle.