In Baculites, a straight shelled ammonite, the constructional limits on shell shape resulting from the limited strength of nacre in tension are circumvented by a system of vaults in the phragmocone.

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 ...

The muscles and organs of an ammonite — an extinct relative of cuttlefish and squid with coiled shells and tentacles — have been reconstructed in 3D for the first time. The achievement has allowed a ...