A common frog species spread across western Ecuador and southern Colombia was formally described as a distinct new species, named Pristimantis milpe, after researchers discovered it had spent more than a century hiding in plain sight under an incorrect scientific name in museum collections.
For more than a hundred years, an abundant amphibian population across the Chocó forests was misidentified due to taxonomic confusion that persisted until researchers revisited historical material. The discovery, detailed in a study published in the international journal ZooKeys, demonstrates that biological surprises are not restricted to rare or elusive animals, as even familiar species can remain misclassified for decades.
Museum Specimens Resolve a Century-Old Taxonomic Error
The breakthrough originated from historical amphibian specimens preserved in the collections of the Natural History Museum in London. A research team led by Santiago Ron, a researcher at the Pontificia Universidad Católica del Ecuador, traveled to England to investigate a long-standing classification puzzle involving specimens collected in Ecuador during the 19th century.
By comparing those historical museum examples with living populations in the Ecuadorian Chocó, the team determined that the old material had been incorrectly assigned to another species. This misassignment left a frequently encountered animal without its own correct designation.
“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,”
Jhael Ortega, a PhD student at Virginia Tech and one of the study authors
Researchers emphasized that connecting historical archive material with living populations remains a vital tool for modern taxonomy. The formal description of Pristimantis milpe corrects the historical record and highlights the continued scientific value of natural history collections.
Habitat, Distribution, and Distinctive Characteristics
Unlike many newly identified species that inhabit isolated or restricted regions, the Milpe Robber Frog is widespread and easily detected. Its known range spans more than 67,000 square kilometers across western Ecuador and southern Colombia, stretching from sea level up to elevations of 1,200 meters. The species occupies diverse environments, ranging from primary forests to urban parks.
Field identification is aided by distinct behavioral and physical traits. The species is nocturnal, with males typically calling from leaves on shrubs and bromeliads several meters above the forest floor.
“Males typically call from leaves on shrubs and bromeliads several meters above the forest floor, producing a loud, distinctive vocalization resembling a “click.””
Source: ZooKeys
Physical differences also help distinguish the frogs. Females feature prominent coloration on the groin and thighs, displaying orange or light blue tones marked by black spots, whereas males exhibit a more uniform appearance.
Conservation Significance in the Ecuadorian Chocó
The region where the frog thrives, the Ecuadorian Chocó forest, supports more than 250 species of amphibians and is recognized as a priority area for biodiversity conservation. The formal classification of Pristimantis milpe underscores how much remains to be understood about regional ecosystems, even among animals that are frequently observed by local residents and researchers alike.
By bridging 19th-century specimens with modern field observations, the study provides a clearer picture of amphibian diversity in South America. The findings point to the necessity of periodically reviewing museum archives to ensure that widely distributed wildlife is accurately documented in scientific literature.
