Ammonite

Ammonites were prehistoric extinct cephalopods that went extinct about 65 million years ago. An incredibly long lived group of animals, ammonites appeared on the planet about 400 million years ago, but only went extinct the same time the dinosaurs did. Ammonites were also very diverse, with a plethora of spiral shells and ranging in size from a few inches to nearly 5 feet across! Despite looking similar to the modern Nautilus, they are more closely related to an Octopus.