Phanerozoic of Pangaea into Laurasia and Gondwana in an extinction known as the Jurassic-Cretaceous extinction. Sea levels rose, destroying fern prairies and creating shallows. Ichthyosaurs became extinct whereas sauropods, as a whole, did not; in fact, some species, like "Titanosaurus", lived until the K-T extinction. The increase in sea-levels opened up the Atlantic sea way which would continue to get larger over time. The divided world would give opportunity for the diversification of new dinosaurs. The Cretaceous is the longest period in the Mesozoic, spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous,
Late Triassic the impact of an asteroid, climate change, or rising sea levels. The Carnian Age is the first stage of the three to occur during the duration of the mass extinction era. The Carnian age developed about 228 to 217 million years ago, and signals the start of the Late Triassic Epoch. The Carnian stage can further be broken down to relative species activity during the time, based on fossils and evidence found dating back to this time period. For example, marine life such as "serenites nanseni" and "Trachyceras Obesum" can be dated back to the early Carnian stage. Meanwhile, "Tropites