About 260 million years ago, Orthacanthus was the terror of freshwater swamps and bayous in Europe and North America. Its eel-like body reached nearly 10 feet in length and its powerful jaws were lined with double-fanged teeth. Here it is about to make a meal of a small "horned" amphibian. Orthacanthus belongs to a group of very successful sharks that lived mainly in fresh waters. They first appeared almost 400 million years ago, and became extinct just before the "Age of the Dinosaurs," about 225 million years ago