Very large Ammonite pair coming from Morocco. This is one Ammonite that has been cut in half and polished revealing the inside of the creature. The small compartments have been replaced with calcite crystals during the fossilization period. The back or outside of the Ammonite has also been polished and revelas some beautiful colors from am opalization process that occurred during fossilization. Great visual display for any room.
With squidlike tentacles extending from their distinctive multichambered shells, the extinct marine predators known as ammonites were once among the most successful and diverse animals on Earth. Scientists have identified more than 10,000 species from fossils found nearly everywhere on the planet where oceans once existed, from the Great Plains of North America to the foothills of the Himalaya and the glaciers of Antarctica.
Ammonite is actually the colloquial term for ammonoids, a large and diverse group of creatures that arose during the Devonian period, which began about 416 million years ago. Ammonoids are related to other cephalopods—such as squid, octopuses, and cuttlefish—and they were early relatives of the modern nautilus. Meanwhile, true ammonites are a suborder of ammonoids that didn’t appear until about 200 million years ago, in the Jurassic period.
During their long history, ammonites survived three mass extinctions—most notably the Permian extinction, a global warming that was brought on by volcanic activity about 252 million years ago, and that killed 96 percent of the planet’s marine species. While many species of ammonites died out in that extinction event, scientists believe the survivors diversified explosively in the million years that followed. Ammonites hunted the planet’s seas until they were entirely wiped out by the same cataclysm that claimed the non-avian dinosaurs about 66 million years ago.
What does ammonite have to do with Fibonacci? Ammonite shells are a naturally occurring example of the Fibonacci sequence. If you draw a quarter circle in each Fibonacci square, they connect to form an ever increasing spiral. Try to find the Fibonacci squares in your ammonite fossils – photocopy the fossil, then start at the very center by drawing two small boxes right next to each other. With most fossils, the first boxes are .25 cm by .25 cm. Continue drawing boxes with Fibonacci dimensions. You’ll notice that the spiral of the shell always falls within the Fibonacci squares.
