The reign of the dinosaurs ended in Spring

INVITATION

#ESRFscience Live Online Seminars

"The reign of the dinosaurs ended in Spring"

Friday, May 20th, 14:00

Please click here to watch the replay of the webinar

Abstract
The Cretaceous–Palaeogene (KPg) mass extinction around 66 million years ago was triggered by the Chicxulub asteroid impact on the Yucatán Peninsula, which caused the highly selective extinction that eliminated ~76% of species, including all non-avian dinosaurs, pterosaurs, and ammonites. The timing of the impact has been studied mainly on millennial timescales, leaving the season of the impact unconstrained. Here, by studying fishes that died on the day the Mesozoic era ended, we demonstrate that the impact occurred during boreal spring. Osteohistology together with stable isotope records of perichondral and dermal bones in acipenseriform fishes from the Tanis impact-induced seiche deposits reveal annual cyclicity across the final years of the Cretaceous period. Annual life cycles drive the seasonal timing and duration of reproduction, feeding, and hibernation, and in many taxa, reproduction and growth take place during spring. We therefore postulate that the seasonal timing of the Chicxulub impact in boreal spring and austral autumn importantly contributed to selective biotic survival across the KPg boundary.