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 ...

We now know ammonites are extinct cephalopod molluscs related to squids and octopuses, which lived in the seas of the Mesozoic Era between about 201 and 66 million years ago. Their shells are ...

Fossils found in the northern part of Hokkaido are a new type of ammonite, the once-ubiquitous spiral-shelled creatures that went extinct with the dinosaurs 65 million years ago, researchers said.