The Eocene-Oligocene transition marks the passage from “greenhouse” conditions to an “icehouse state” with progressive global cooling starting in the early middle Eocene. The late Eocene is also characterized by a high concentration of extraterrestrial impacts, the effects of which, on living organisms and climatic changes, are still not understood. We carried out a high-resolution investigation on planktonic foraminiferal assemblages in an 8-m-thick segment of the Massignano global stratotype section and point for the Eocene-Oligocene boundary with the aim of assessing the effects that the impacts may have had on the environment and this group of organisms. The studied interval...