Trilobites became extinct at the end of the Permian (~252 Ma), during the largest mass extinction in Earth history (the 'Great Dying'), which eliminated ~90–96% of marine species. Graptolites became extinct earlier, by the Late Devonian. Ammonites survived the Permo-Triassic extinction but went extinct at the end-Cretaceous (K-Pg, ~66 Ma). Ediacaran biota disappeared at the Precambrian–Cambrian boundary (~541 Ma).