Global key areas for anuran tadpole discovery

Abstract Anurans are the most threatened group of tetrapods. Although the number of Data Deficient species has been drastically reduced during the latest global assessment, there remain crucial gaps in knowledge about their biology. For more than half of all species, their larval stages are entirely unknown, posing a major obstacle to effective conservation. This is especially important for species with a biphasic life cycle, in which drivers of extinction can impact tadpoles and adults differently. To address this, we integrated global data on anuran tadpoles with ancestral state reconstructions and Geographic Information System based analyses to identify key areas for discovering free-living tadpoles. Our results show that strategically focusing research on 0.25% of Earth’s terrestrial surface could reveal more than half of the undescribed tadpoles, and covering 1% could account for all of them. These priority areas are concentrated mainly in biodiversity hotspots and include the Tropical Andes, Eastern Brazil, Tropical Africa, India, Southeast Asia and New Guinea. Each region exhibits unique ecological and evolutionary traits in anuran larval diversity, highlighting their importance for targeted research. Given the alarming rate of habitat loss and the high biodiversity within these regions, this study underscores the need for urgent conservation efforts to protect both known diversity and diversity yet to be discovered.