Mediterranean marine keystone species on the brink of extinction.

For over two decades, marine heatwaves (MHWs) have triggered invertebrate disease outbreaks leading to mass bleaching and mortality events. A severe MHW hit the Mediterranean Sea in 2022, affecting key components of coastal marine ecosystems, among which bath sponges were the main victims. The Marseille region (NW Mediterranean) was one of the last refuges for these species, which have been harvested since Antiquity, but the 2022 MHW is here reported to have led this entire poriferan family to the extinction of all known dense populations.