Eukaryote
Eukaryotes evolved in the Proterozoic eon. The oldest known eukaryote is Grypania, a coiled, unbranched filament up to 30 mm long. The oldest Grypania fossils come from an iron mine near Negaunee, Michigan. The fossils are dated as 1874 million years old. Grypania lasted into the Mesoproterozoic era.