Back from the dead: “Extinct” fish rediscovered in a remote Bolivian pond after 20 years

The species had not been observed for more than 20 years. Its original habitat was destroyed and converted into farmland, and repeated searches over the years failed to locate any surviving individuals. As a result, Moema claudiae was classified as Critically Endangered under IUCN criteria and widely believed to be possibly extinct.

A Surviving Population Found in a Remote Pond

During a recent field expedition, researchers Heinz Arno Drawert and Thomas Otto Litz made a breakthrough. They discovered a living population of Moema claudiae in a small, temporary pond located within a fragment of forest surrounded by agricultural land.

This marks the first confirmed record of the species in more than two decades. The discovery, published in the open-access journal Nature Conservation, allowed scientists to photograph the fish alive for the first time. It also gave researchers the opportunity to observe its behavior and investigate aspects of its natural history that were previously unknown.

A Personal and Scientific Milestone

Thomas Litz, one of the study's co-authors, described the rediscovery as deeply meaningful. "For me, it is something special to have rediscovered Moema claudiae. This has shown that we now have the opportunity to preserve this species in the wild. I am all the more pleased because Prof. Wilson Costa named this species after his wife Claudia, and I would like to take this opportunity to thank him especially for decades of collaboration and support."

A Global Hotspot for Seasonal Killifish Diversity

The rediscovered site turned out to be remarkable for more than just one species. In addition to Moema claudiae, researchers identified six other species of seasonal killifish in the same habitat. This makes it the most genetically diverse assemblage of seasonal killifish ever documented anywhere in the world.

The area sits at a unique ecological crossroads where the Amazon forest meets the Llanos de Moxos savannas. This transition zone appears to support exceptional biodiversity. However, widespread deforestation and expanding agriculture are rapidly reducing these habitats.

Urgent Calls for Habitat Protection

Following the discovery, scientists stressed the need for immediate conservation action. The newly identified site is currently the only known location that supports a wild population of Moema claudiae. It is also an important global center of seasonal killifish diversity.

Over the past 25 years, Bolivia has lost nearly 10 million hectares of forest, including critical wetlands. The pace of deforestation has increased sharply in recent years, putting many unique species and ecosystems at risk.

"Without rapid and effective action to curb the irrational expansion of the agricultural frontier in Bolivia's lowlands, we risk losing some of the world's most important terrestrial and aquatic ecosystems, and with them the irreplaceable goods and services they provide," said co-author Heinz Drawert. "We cannot hope to achieve true social and economic well-being unless we also maintain the functionality of the ecosystems that sustain it."