Ammonite - Dactylioceras sp.

The Dactylioceras genus of ammonites scavenged along the ocean floor of the Jurassic Period, about 180 million years ago.  This ammonite is named after the Greek word dactyl meaning "fingers" because of the many straight ribs on its relatively small but strong shell. Mass mortality specimens are found all over the world, especially in Europe, indicating Dactylioceras may have died shortly after traveling to a specific area for spawning, allowing their shells to wash up in large quantities on the banks of the Jurassic seas.  Ammonites are extinct shelled cephalopods that are most closely related to today’s octopus, squid and cuttlefish. The earliest ammonite appeared in the oceans during the Devonian period 360 million years ago and disappeared with the dinosaurs just 66 million years ago. All had buoyant chambered shells that they lived in, sealing off old, too-small chambers as they grew with walls called “septa,” and moving into bigger ones. They moved by jet propulsion, expelling wa