Ammonites are a group of extinct shelled cephalopods related to today's squids and octopuses. Most ammonites died out 66 million years ago, at the same time as dinosaurs. Fossilised ammonite shells ...

Based on the fossil record, ammonites came in a wide range of sizes and shapes, from smaller than an inch to as large as nine feet wide. Some ammonites had long, straight shells, while others had ...