The Permian/Triassic extinction event (P/Tr for short and also popularly referred to as the Great Dying) was the largest extinction event in the Phanerozoic eon. 57% of all biological families, 83% of all genera, 96% of all marine species (including many kinds of fish and the last surviving trilobites) and 70% of all terrestrial vertebrates (including many of the large amphibians, primitive reptiles and synapsids) became extinct. It is the only known extinction event of insects. It ended the Palaeozoic era, and began the Mesozoic era.