They were connected to the shell by intricate lines known as sutures—the complexity of which varied tremendously throughout this animal’s evolution. The many chambers of their shells likely ...

Ammonite fossils, an example is shown here ... This supports Darwin's theory of evolution, which states that simple life forms gradually evolved into more complex ones. Evidence for early forms ...

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.