5 Astonishing Ammonite Facts

Ammonites, with their iconic spiraled shells, are one of the most recognizable fossils. These marine creatures thrived in Earth's oceans for over 300 million years.

This article delves into the fascinating world of ammonites, from their biology to their significant role in paleontology.

What are Ammonites?

Ammonites are extinct marine mollusks that belonged to the subclass Ammonoidea.

They are closely related to current-day cephalopods like octopus, squid, and cuttlefish.

These creatures existed from the Devonian to the end of the Cretaceous period, approximately 400 to 66 million years ago.

Physical Characteristics

• Spiraled Shell:

  The most defining feature of ammonites is their coiled, chambered shell. This shell often displays intricate patterns and can range in size from tiny specimens, just a couple of centimeters in diameter, to massive ones measuring over two feet.

• Sutures:

  These are the lines where the walls of the shell's chambers, called septa, meet the outer shell. The complexity of these suture lines can be used to determine species and age.

• Tentacles and Beak:

  While the soft body of the ammonite rarely fossilizes, it's believed they had numerous tentacles and a beak, much like their modern-day relatives.

Ecology and Behavior

Ammonites were marine animals, and many species floated in the open water, thanks to the buoyancy provided by their chambered shells.

By adjusting the gas and liquid content of these chambers, ammonites could likely control their buoyancy and movement. They were primarily carnivorous, feeding on smaller marine animals.

Significance in Paleontology

Ammonites play a crucial role in the field of paleontology for several reasons:

• Biostratigraphy:

  Due to their vast distribution over time and space and their rapid evolution, ammonites are excellent index fossils. This means they can help date other fossils and rock layers.

• Extinction Events:

  The abundance of ammonites and their presence through several geological periods make them valuable in studying mass extinction events, including the one that wiped out the dinosaurs.

Cultural and Commercial Importance

• Ammolite:

  Some ammonite fossils, especially those found in Canada, can turn into gemstones called ammolite. This iridescent gemstone is rare and sought after for jewelry.

• Cultural Significance:

  In some cultures, ammonite fossils are seen as symbols of luck or spiritual icons. The name 'ammonite' itself is derived from the Egyptian god Ammon, as they resemble his ram horns.

Extinction

Ammonites, along with many other marine species and the non-avian dinosaurs, went extinct during the Cretaceous-Paleogene (K-Pg) extinction event around 66 million years ago.

The exact cause remains a topic of debate, but the leading theories include a massive asteroid impact and increased volcanic activity.

Conclusion

Ammonites, with their iconic spiraled shells, are not just relics of a bygone era; they are windows into our planet's history.

They teach us about ancient marine environments, Earth's shifting continents, and the ever-evolving tree of life. Through these fossils, we can unravel stories of resilience, adaptation, and ultimately, extinction.