The term Middle Miocene disruption, alternatively the Middle Miocene extinction or Middle Miocene extinction peak, refers to a wave of extinctions of terrestrial and aquatic life forms that occurred around the middle of the Miocene, roughly 14.8 to 14.5 million years ago, during the Langhian stage of the Miocene.
Madelaine Bohme observed the occurrence of Varanidae, Chameleon, Cordylidae, Tomistominae, Alligatoridae, and giant turtles which indicate survival through the Miocene Climatic Optimum (18 to 16 Ma) in Central Europe (45-42°N palaeolatitude). A major and permanent cooling step occurred between 14.8 and 14.1 Ma, associated with increased production of cold Antarctic deep waters and a major growth of the East Antarctic ice sheet. Two crocodilians of the genera Gavialosuchus and Diplocynodon were noted to have been extant in these northern latitudes prior to the permanent cooling step then became extinct 13.5 to 14 Ma.
A Middle Miocene delta18O increase, that is a relative increase in the heavier isotope of oxygen, has been noted in the Pacific, the Southern Ocean and the South Atlantic.