Eurypterus (/juːˈrɪptərəs/ ew-RIP-tər-əs) is an extinct genus of sea scorpions. They existed during the Silurian Period, from around 432 to 418 million years ago. There are fifteen species belonging to the genus Eurypterus, the most common of which is Eurypterus remipes, the first eurypterid fossil discovered and the state fossil of New York.