A rare amphibian once thought to be extinct has resurfaced in Chile, marking a remarkable scientific breakthrough. Alsodes vittatus, a small frog known only from old records and a single specimen, has been rediscovered after over 120 years in the wild. This rediscovery is being hailed as one of the most exciting amphibian finds in South America this decade.
The vanished amphibian: A century of silence
Alsodes vittatus, an endemic frog from Chile, had been lost to science for over a century. The species was first described by the German-born naturalist Rudolph Amandus Philippi in 1902, who noted a distinctive feature: a yellowish stripe running the length of its back.
After Philippi’s description, however, the species vanished from the scientific community, with no confirmed sightings or specimens since then. Despite numerous efforts between 1995 and 2002 to locate the species, the frog remained elusive, and it was feared that it might have been extinct, or even never a valid species to begin with.
A detective story in the Andes
The story of Alsodes vittatus’ rediscovery is as much about historical detective work as it is about biology. The research team, led by Dr. Claudio Correa from the Universidad de Concepción, took on the task of piecing together clues from the past.
They studied travel accounts from Philibert Germain, a French entomologist who collected the original specimens in 1893, mapping his journey across the Andes to the Hacienda San Ignacio de Pemehue, now situated on the border between Chile’s Biobío and La Araucanía regions.
Their historical sleuthing directed them to specific valleys in the Andean foothills, where they focused their searches. From 2015 to 2024, the researchers embarked on field expeditions, primarily at night when the frogs are most active. Their perseverance bore fruit in 2023 and 2024, when they discovered five previously unknown populations of Alsodes frogs.
Of these, three were confirmed to be the long-lost A. vittatus, inhabiting remote streams at elevations between 1,421 and 1,610 meters. These streams, cold and rocky, are nestled among temperate forests featuring the iconic monkey puzzle trees.
Surprising twists: The frog’s secret life revealed
The rediscovery of Alsodes vittatus revealed unexpected surprises. Researchers observed variations in the frog’s appearance, notably the yellowish stripe that had been considered a defining feature of the species. In some individuals, this stripe was prominent, while in others, it was completely absent.
This variation had never been documented before, and it provides an explanation for why earlier searches had failed to locate the species—different populations might have had subtle differences in their physical appearance.
DNA analysis also brought an unexpected twist. The Alsodes vittatus populations were found to be genetically close to Alsodes neuquensis, a species previously known only from Argentina. Surprisingly, one specimen of A. vittatus was genetically closer to A. neuquensis than to other A. vittatus individuals from the same location.
This raises intriguing questions about whether the two species might actually be a single species that spans both sides of the Andes, warranting a revision of their taxonomic status.
The conservation race: Is it too late for the frog?
While the rediscovery of Alsodes vittatus is exciting, its future remains precarious. The frog’s habitat is incredibly limited, covering just about eight square kilometers, and is under constant threat from deforestation, the expansion of livestock grazing, invasive species like introduced trout (which may prey on tadpoles), and the looming dangers of climate change.
Researchers have recommended a reassessment of the frog’s conservation status, suggesting a move from Critically Endangered to Endangered, though the species still faces substantial threats.
During their surveys, the researchers observed notable diversity in the frogs’ coloration. Adult males ranged from light brown with yellow and green hues to olive brown, while some juveniles showed darker brown colors.
In one particularly exciting discovery, the researchers found smaller frogs with a dark brown stripe, closely matching Philippi’s original illustration from 1902. This suggested that Philippi may have based his classification on juvenile specimens rather than adults, solving another piece of the century-old mystery.
Beyond the findings of A. vittatus, this research carries important broader implications. It reinforces the idea that species thought to be extinct may still persist in hidden corners of the world. It also highlights significant gaps in our knowledge of Andean amphibians, suggesting that there may be many more undiscovered species awaiting detection in these remote and often overlooked ecosystems.
TProtecting the future of Chile’s amphibians
For now, though, Alsodes vittatus offers a rare glimmer of hope in a world where many species are slipping into extinction. This rediscovery demonstrates the importance of continued exploration and conservation efforts.
With specific habitat information now available, the focus can shift toward protecting the critical areas where these frogs live. However, the frog’s survival will depend on effective action to curb the threats facing its habitat, from climate change to invasive species.
