Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma (million years ago). The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene).

At the end of this period, there was a mass extinction commonly referred to as the Cretaceous–Paleogene extinction event, as well the Cretaceous–Tertiary extinction event. At this extinction event, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser known groups, died out.