Undescribed species have higher extinction risk than known species

Newly discovered species are often threatened with extinction but in many cases have received limited conservation effort. To guide future conservation, it is important to determine the risk of newly described species. Here, we test how time since formal description a linked its threat status obtain better insight into possible and as yet undescribed We compiled IUCN Red List data for 53,808 from five vertebrate groups 1758. Extinction more recently has increased significantly over time; proportion among 11.9% between 1758 1767 30.0% those 2011 2020. Based on projections our analysis, this could further increase 47.1% by 2050. The pattern consistent across taxonomic biomes. Current rates estimated all known therefore highly likely be underestimated. Intensive fieldwork boost discovery new immediate action species, especially tropical areas, urgently required.