An international research team has identified seven previously undescribed species of Madagascar’s elusive diamond frogs (Rhombophryne), adding new evidence that this unusual amphibian group is far more diverse than scientists once realized.
Accurately identifying species and understanding where they live are essential for measuring biodiversity and protecting it. To sort out the identities of these frogs, researchers combined field observations, museum specimens, and advanced DNA analysis. The work revealed previously hidden species diversity and helped resolve a taxonomic problem that had remained unsettled for years.
By determining which frogs belong to which species and mapping where they occur, the researchers have also created a stronger scientific basis for conservation in Madagascar, where many forests are rapidly disappearing.
“Diamond frogs have been hiding their diversity beneath our feet,” said Dr. Mark D. Scherz, Curator of Herpetology at the Natural History Museum Denmark and lead author of the study.
“Many species spend most of their lives beneath the leaf litter, and even when they emerge they can look deceptively similar,” he added.
Madagascar’s Secretive Diamond Frogs
Diamond frogs are some of Madagascar’s most distinctive amphibians. Certain species are extremely round and resemble the rain frogs found in mainland Africa, spending much of their time concealed beneath the forest floor. Other species have long legs and live among moss, while some are sturdier frogs adapted to life on the ground.
Most diamond frogs look brown at first, but several species have vivid markings that remain hidden until the frogs move. These can include bright orange flashes or bold white and black patterns on the thighs and lower back. Researchers think these markings may help startle predators.
Because these frogs are so difficult to find and observe, diamond frogs remain among the least studied vertebrates in Madagascar.
A 12 Year Scientific Puzzle
The research effort began more than twelve years ago, when scientists repeatedly encountered frogs that clearly appeared to represent species that had never been formally described. Identifying them was not simple, however, because researchers had trouble matching older species names with the genetic lineages found in modern specimens.
“When I started this project twelve years ago, we already knew there were several species waiting to be described, and almost every expedition to Madagascar revealed another one. Some were relatively straightforward to describe, but others were complicated by uncertainty surrounding older species names. Untangling that puzzle took years,” Scherz said.
A major breakthrough came from museomics, the use of DNA sequencing on historical museum specimens. Researchers compared genetic information from old collections with DNA from newly collected frogs. They also examined external features, skeletal anatomy, and frog calls.
Together, those lines of evidence allowed the team to connect historical species names with the correct evolutionary lineages and clear up taxonomic confusion that had persisted for decades.
Museum collections played a central role in establishing the identities of several of the species.
“Museum collections are far more than archives of the past – they are essential scientific resources for understanding biodiversity today,” said Dr. Alice Petzold of the University of Potsdam, who led the museomics work.
“By sequencing historical specimens, including the original type specimens, we were able to answer questions that have persisted for generations,” she added.
New Species Could Shape Conservation
The study was carried out through close cooperation among scientists and institutions in Madagascar and Europe. It also highlights the direct connection between biodiversity research and conservation.
Many diamond frogs live in forests that are becoming increasingly fragmented by deforestation. At the same time, scientists still know very little about the basic biology of many of these species.
“For many species, we still know almost nothing about their breeding biology, population sizes or ecological requirements. Without that knowledge, it becomes much more difficult to assess their conservation status and protect them effectively,” said co-author Dr. Andolalao Rakotoarison of the Institut d’Enseignement Supérieur de Soavinandriana Itasy, Madagascar.
The new findings are already contributing to conservation planning in Madagascar. At a protected area planning workshop held in March 2026 as part of the country’s Biodiversity 30×30Program, several of the newly described frogs, including Rhombophryne quentini, directly informed proposals aimed at strengthening and expanding protected areas.
More Frogs May Still Be Waiting
With the addition of seven new species, the number of known Rhombophryne species has risen to 27. Even so, the researchers believe more unnamed species are almost certain to remain undiscovered and undescribed.
The new study resolves many long-standing questions, but Scherz views it as the start of a much larger effort.
“Every newly described species represents millions of years of unique evolutionary history. The more we learn about Madagascar’s remarkable amphibians, the clearer it becomes that there is still an enormous amount left to discover,” he said.
