A gruelling two-day trek into the remote upper Pastaza basin has revealed a new inhabitant of the Ecuadorian Andes: Pristimantis fergusoni. In a new study published in the open-access journal ZooKeys, a research team led by Juan Pablo Reyes-Puig of Fundación EcoMinga and the Instituto Nacional de Biodiversidad (INABIO) has recently described this fascinating species of spiny frog.
Taxonomy and Fieldwork
Reyes-Puig discusses the primary motivations behind the team’s study:
“Due to its great diversity, Pristimantis is a genus that requires constant taxonomic work, especially in remote and little-studied areas. One such area is the upper Pastaza basin in the central Andes of Ecuador.
Although we have studied this region for almost two decades, each new exploration brings surprises, such as the case of the new Pristimantis fergusoni.”
This constant taxonomic revision stems from the sheer scale of the genus; frogs of the Pristimantis group currently comprise 626 species. Historically, limited scientific funding meant that many of these were described primarily on the basis of morphological evidence.
Fortunately, this has been increasingly remedied over the last decade as a growing community of taxonomists in Colombia, Ecuador, and Peru combine molecular and morphological data to identify and classify new species.
However, carrying out fieldwork in these remote regions remains a formidable challenge. Reyes-Puig highlights the physical demands of conducting herpetological research in the upper montane forests of the eastern Ecuadorian Andes:
“First, it is quite challenging to reach the location after nearly two days of hiking. Then, the cold and almost constant humidity are physical limitations after fatigue, but observing a habitat untouched by humans and species never seen before, such as Pristimantis fergusoni, are a real reward.”
That reward is visually striking. While many frogs in the Pristimantis genus rely on camouflage to blend into the forest floor, P. fergusoni carries a distinct flash of color. The species exhibits notable sexual dimorphism: males are more muted, whereas females possess a bright scarlet belly.
The exact reason for this vivid coloring remains a mystery, though Reyes-Puig notes a few plausible theories:
“Knowledge about the behavior and natural history of the new species is very limited, but we believe that the bright colors could serve for communication during courtship or as part of their reproductive strategies.”
Notably, this new species is named after Robert T. Ferguson II, an amateur naturalist who dedicated his life to protecting reptiles and amphibians. As a citizen scientist, Ferguson mapped wildlife in the US and helped fund the protection of rainforests in Latin America. Through his photography and work with groups like Rainforest Trust, he inspired others to care for the wild.
A Biodiversity Hotspot Under Pressure
The discovery of P. fergusoni is likely just the beginning, with the upper Pastaza basin serving as a taxonomic frontier where many more species await identification. Reyes-Puig estimates that at least eight more new species of amphibians are currently waiting to be described in this region alone.
For now, Pristimantis fergusoni is listed as “Data Deficient” by the IUCN because it has only been found in two locations close to one another – the Cerro Candelaria and Chamana Reserves – leaving scientists without the population data needed to determine its level of risk. However, the team is already working to ensure the frog’s future isn’t left to chance.
“Taxonomic work is usually limited to describing new species,” says Reyes-Puig. “We have gone a step further by ensuring the protection of the new species’ habitat through the declaration of protected areas.”
While this work happens on the ground in the Llanganates-Sangay Ecological Corridor, Reyes-Puig stresses that protecting these species requires global awareness. Climate change and habitat loss are universal threats to amphibians, and local conservation efforts rely on broader environmental responsibility:
“Small actions such as recycling, waste management, and sustainable activities are important. We know that climate change is a problem that affects amphibians worldwide, but small actions [from the public] are also crucial.”
The presence of P. fergusoni is a testament to the region’s immense biodiversity, and a reminder that in the underexplored Andes, discovery and conservation must move at the same urgent pace.
Original source:
Reyes-Puig JP, Yánez-Muñoz MH, Ron SR, Venegas PJ, Ortega J, Carrión-Olmedo JC, Reyes-Puig C (2026) A new spiny frog of the genus Pristimantis (Anura, Strabomantidae) from the eastern slopes of the Ecuadorian Andes. ZooKeys 1269: 83-105. https://doi.org/10.3897/zookeys.1269.162260
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