The process of opalization refers to something turning into an opal — like for example, a big part of this fossil. Opalized ammonite fossils are formed through a unique geological process ...

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 ...

Ammonites were shelled cephalopods that died out about 66 million years ago. Fossils of them are found all around the world, sometimes in very large concentrations. The often tightly wound shells of ...

Some ammonites had spines for defence and others would have had ornamentation that may have served to strengthen their shells. Around 180 million years ago in the Jurassic period, Dactylioceras lived ...

To address this, the team assembled a new database of Late Cretaceous ammonite fossils, drawing on museum collections to fill sampling gaps and provide a more accurate picture of ammonite ...

Ammonite fossils, an example is shown here, are sea creatures that became extinct about 65 million years ago. Fossil remains have been found in rocks of all ages. Fossils of the simplest organisms ...