Trilobites - The Oldest Living Fossils

In our timeline, Trilobites went extinct about 251 million years ago as a result of The Great Dying. In this timeline they came pretty close - with all but one species going extinct. This single species survived by leaving the water and moving onto land where it quickly diversified.

Today there are around 4,200 species of Trilobite. A far cry from their peak at 20,000 during the Cambrian, but impressive nonetheless. They can be found on every continent except Antartica and prefer habitats such as swamps, deserts, caves, jungles, sewers and dumps.