Ammonite

Ammonites floated through the world's shallow oceans for more than three hundred million years, and their fossilized shells turn up all around the world.

Visit the Jurassic Coast World Heritage Site in the UK, and ammonite road signs greet you at every town and city and even the lampposts on the seafront feature a familiar coiled shell.

There are a few well known shelled giant cephalopods from the fossil record. Some of the largest recorded ammonites are in the genus Parapuzosia, fossils of which reach up to 2m in diameter.