Scientists from Pontificia Universidad Católica del Ecuador (PUCE) have identified Pristimantis milpei, a widespread frog species that was mistakenly classified as another species for more than a century. The discovery was made by studying 19th-century frog specimens from Ecuador preserved at the Natural History Museum in London.
The discovery is significant because many newly described amphibian species are rare or limited to small geographic areas. In contrast, the Milpe robber frog, Pristimantis milpei, is widespread and relatively easy to detect because of its distinctive nocturnal call. Its known range covers more than 67,000 square kilometers, from elevations of approximately 1,200 meters above sea level across the Chocó forests of western Ecuador and southern Colombia.
The formal description of Pristimantis milpei was published in the international journal ZooKeys, which specializes in biodiversity and taxonomy.
A century-old case of mistaken identity
Researchers identified Pristimantis milpei by reexamining historic amphibian specimens held at the Natural History Museum (NHM) in London.
Santiago Ron, a PUCE researcher and lead author of the study, traveled to the United Kingdom to investigate a classification problem that had remained unresolved for more than 100 years. He examined original reference specimens, known as “types,” which were collected in Ecuador during the 19th century and preserved in museum collections ever since.
By comparing these historical frogs with living Chocó frog populations in Ecuador, the researchers discovered that the older specimens had been incorrectly assigned to another species. As a result, frogs observed and documented regularly for decades had never received their own scientific name.
“The fact that such a common species went unnoticed for decades under a mistaken name highlights the importance of properly linking scientific names to natural populations,” said Jael Ortega, a doctoral student at Virginia Tech and one of the study’s authors.
Meet the Milpe robber frog
The Milpe robber frog, Pristimantis milpei, is active at night. Males typically call from shrubs and bromeliad leaves several meters above the forest floor. Their loud, distinctive calls produce a sound similar to a clicking noise.
Male and female Milpe robber frogs also have noticeably different appearances. Females display bright coloration around the groin and thighs, with orange or light-blue tones next to black spots. Males generally have more uniform coloration.
The species lives in the Chocó forests of Ecuador and southern Colombia, a region recognized as one of the world’s most important biodiversity hotspots.
Why historic museum collections remain important
This discovery demonstrates the continuing scientific value of natural history collections. Specimens preserved for decades or centuries allow researchers to revisit outdated classifications, compare physical characteristics, and answer questions that could not be resolved by earlier scientists.
In this case, combining 19th-century museum specimens with observations of living frog populations enabled researchers to confirm that Pristimantis milpei deserves recognition as a distinct species.
The findings also reveal how much remains to be discovered about Earth’s biodiversity. Even common and widespread animals can conceal scientific surprises, and solving these mysteries often requires combining historical collections with modern field research and wildlife observations.
Source: www.sciencedaily.com