Ammonite survival across the Cretaceous–Paleogene boundary confirmed by new data from Denmark

New evidence from Stevns Klint, Denmark, confirms that ammonites survived the Cretaceous–Paleogene extinction event. Researchers analyzed fossil specimens from the Cerithium Limestone Member, revealing that most ammonites in this unit are autochthonous Danian survivors, not redeposited Maastrichtian fossils. Only one specimen was identified as reworked from the Maastrichtian era. The study combines taphonomic and sedimentological analyses to support this conclusion, challenging previous assumptions about ammonite extinction. This finding raises questions about what ultimately caused the demise of the last surviving ammonites on Earth.

Machalski, M., Olszewska-Nejbert, D., Landman, N. H., Jagt, J. W. M., Garb, M., & Milàn, J. (2025). Ammonite survival across the Cretaceous–Paleogene boundary confirmed by new data from Denmark. Scientific Reports, 15(1). https://doi.org/10.1038/s41598-025-34479-1