Collection: Ammonite

The ammonite is an iconic marine fossil animal, best known for its spiral-shaped shell.

🌊 What is an ammonite?

The ammonite is a cephalopod mollusk (like modern-day squid and octopus) that lived in the seas between about 400 and 66 million years ago. It disappeared along with the dinosaurs at the end of the Cretaceous period.

🐚 Characteristics of ammonite

• Spiral shell : This is the most well-known part. It is usually flat and spirally wound, with internal compartments.

• Compartments (lodges) : The animal lived in the last lodge; the others were used to regulate buoyancy using a gas system.

• Size : Size ranged from a few centimeters to over 2 meters in diameter for the largest species.

• Lifestyle : Carnivore, it captured small animals with its tentacles.

🦕 Evolution and extinction

• Ammonites evolved very quickly, giving rise to a multitude of different species.

• This makes them excellent stratigraphic fossils , very useful for dating geological layers.

• They became extinct during the Great Cretaceous Extinction , probably due to a combination of meteorite impact and rapid climate change.

🪨 Ammonite fossils

• They are often found in sedimentary rocks throughout the world.

• Some are exceptionally well preserved, sometimes with a pearly shell.

• Others have been pyritized (filled with pyrite, or "fool's gold"), which gives them a golden metallic appearance.

🔍 Fun fact

The name "ammonite" comes from the Egyptian god Ammon , often depicted with spiral horns, similar to the animal's shell.