A frog species last seen in 1922 was found again in Ecuador’s southern Andes during a 2022 research expedition to the Quitahuaycu Conservation Reserve. The team of biologists confirmed the rediscovery with genetic analysis.
The Molleturo robber frog (Pristimantis ruidus) classified as “possibly extinct” for several decades, remained elusive due to its small size, under 3 centimeters (1 inch), allowing it to hide in the dense vegetation of the Andean Molleturo Forest in Azuay province.
Its lack of visible eardrums, warty skin and distinctive W-shaped back ridges finally brought the amphibian back into the scientific limelight when a team from San Francisco University in Quito, led by biologist Juan Sánchez-Nivicela, stumbled upon two frogs.
“We were in the forest near a small stream when one of our colleagues noticed a small frog on some fallen logs. We all rushed over to check, but at the time, we didn’t know what species it was,” Sánchez-Nivicela told Mongabay in a phone interview. “Later, back in the lab, we realized it was Pristimantis ruidus, a species no one alive today had ever seen. It was an incredible surprise.”
Their discovery gave science completely new data — what the frog really looks like, its size and genetic information, which had never been available before, he added.
The last previous sighting was by British American zoologist George Tate, who captured 16 frogs of the same species in 1922. Now, a century later, two of the elusive frogs are stored at Ecuadorian science institutes.
Preserving the frogs, Sánchez-Nivicela said, allows for detailed study and long-term reference. Tissue samples from the liver were taken for DNA analysis.
Crucially, the team found signs that the species is still reproducing. One female had developed ovaries and the other was juvenile, suggesting the population is viable and these were not the last individuals.
María del Carmen Vizcaíno, the director of the Ecuadorian Alianza Jambato for Amphibian Conservation, said this rediscovery is another reason to protect the habitat for several species at risk of extinction.
Ecuador’s southern Andes are among the most fragmented ecosystems in the region, retaining only 30% of their original forest cover, largely due to illegal logging and mining.
“Finding a lost species is only the first step,” Vizcaíno said in a phone interview. “We need to ensure that we put in place the necessary measures to protect its habitat, or we risk losing it again.”
Although Ecuador’s amphibians are highly diverse, with more than 630 species, 35% are endangered or critically endangered, according to the International Union for Conservation of Nature’s Red List.
“Our work isn’t done — this area holds a lot of biodiversity that we are just beginning to understand,” Sánchez-Nivicela added. “We hope to return in the rainy season to search for another species we believe may also be hiding in the forest.”
Banner image: A Pristimantis ruidus frog, rediscovered in Ecuador’s Andes after 100 years, found during a 2022 expedition. Image courtesy of Juan Sánchez-Nivicela.
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