Global environmental drivers shape Cenozoic neoselachian diversity and identify modern conservation priorities

Sharks, rays and their immediate extinct ancestors (Neoselachii) are some of the ecologically most impactful marine vertebrates. Despite their evolutionary success, the deep-time patterns of neoselachian diversity and turnover as a response to environmental perturbations remain understudied. Past studies have focussed on taxonomic richness while neglecting changes in faunal composition and ecological strategies, limiting our understanding of macroevolutionary resilience and vulnerability of neoselachians. Consequently, the extent to which major Cenozoic environmental shifts affected neoselachian diversity and turnover remain elusive. Here, we present a sampling-standardised analysis of Cenozoic neoselachian genus diversity and faunal composition change, using high-resolution fossil occurrence data and ecological and environmental variables. We demonstrate a milder impact of the KPg mass extinction on neoselachians than previously suggested, followed by a radiation culminating in an Eocene diversity peak, which is systematically documented and described for the first time using sampling-standardised data. Additionally, we identify two distinct faunal shifts during the Miocene. Shallow, heterogeneous habitats emerged as the primary diversification driver, although responses varied across ecological and taxonomic groups. These findings shed light on the evolutionary and ecological dynamics that shaped modern neoselachian diversity and provide critical context for assessing their vulnerability to ongoing anthropogenic pressures and informing conservation strategies.