the overlying assemblages. In both Russia and South Africa, this transition was associated with the extinction of the previously dominant group of therapsid amniotes, the dinocephalians, which led to its later designation as the dinocephalian extinction. Post-extinction origination rates remained low through the ''Pristerognathus'' Assemblage Zone for at least 1 million years, which suggests that there was a delayed recovery of Karoo Basin ecosystems.

After