Evolutionary biologist Santiago Ron and his peers at the Pontifical Catholic University of Ecuador have recently discovered a new frog species that was hiding in plain sight for over a century.
Unlike other species that are new to science — which are often rare or restricted to certain regions — the Milpe robber frog is widely distributed across 16 million acres in the Chocó forests of western Ecuador and southern Colombia.
It’s also incredibly easy to detect, thanks to a mating call that sounds remarkably similar to the chirp of a smoke detector.
Researchers set the record straight on the Milpe robber frog in a new study published in the international journal ZooKeys on July 24.
“The Pristimantis milpe is one of the most widespread species of Pristimantis in the Pacific basin,” Ron and his co-authors observed.
Santiago R. Ron
“Moreover, it can be locally abundant and conspicuous due to its loud advertisement call … Therefore, it is astounding that such a common species remained undescribed until now.”
The frogs are also fairly easy to distinguish within their own species. Females have a distinctive coloration on the groin and thighs, featuring orange or light blue markings mixed with black spots, while males exhibit more uniform golden-brown coloration.
The color variation in adult males of Pristimantis milpe. Santiago R. Ron
“The fact that such a common species remained ‘invisible’ to taxonomy highlights the importance of correctly establishing the link between the name-bearing types and natural populations,” the researchers said.
The color variation in living adult/subadult females of Pristimantis milpe. Santiago R. Ron
For over a century, the Milpe robber frog had been mistaken for the Pristimantis subsigillatus, or Salidero robber frog.
“Upon re-examination of the holotype of Pristimantis subsigillatus, we conclude that the populations currently ascribed to P. subsigillatus are not conspecific with the holotype,” the researchers wrote, meaning they were not “of the same species.”
Instead, it was more closely related to P. latidiscus, a species that had been described four years prior from a nearby locality.
Santiago R. Ron
The discovery effectively left a population of frogs — historically misidentified as P. subsigillatus — without a valid scientific identity.
“That such a common species has gone unnoticed under the wrong name for decades highlights the importance of correctly connecting
scientific names with living populations in nature,” said biologist Jhael Ortega, a Ph.D. student at Virginia Tech and one of the study authors.
This isn’t the first time an animal has been mistaken for another for decades. In 2025, entomologist Peter Huemer examined 100 specimens of a moth that scientists had long identified as the common oak carcina moth, Carcina quercana.
Using genetic analysis, he determined that some of these moths were actually a genetically distinct species called Carcina ingridmariae.
The discovery was made in Northern Cyprus, which is located roughly 40 miles south of Turkey and widely considered one of the Mediterranean basin’s most biologically diverse regions.
“It is without doubt the prettiest species I have encountered in my long scientific career,” Huemer said in a press release.
So he named it after his wife and lab partner.
“The new [species] is dedicated to my wife, Ingrid Maria, who for so many years accompanied and supported me during fieldwork and long hours of analysis in the laboratory,” Huemer wrote in the scientific journal Alpine Entomology.
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Featured Image: Santiago R. Ron
