Rare Caumatosphinctes polygyralis Ammonite Fossil, Bajocian Jurassic, Authentic Calvados France Marine Invertebrate with Certificate

Description

Authentic Jurassic Ammonite Fossil

This listing features a genuine Caumatosphinctes polygyralis Ammonite Fossil from the Bajocian Stage of the Jurassic Period, discovered in Calvados, Normandy, France. Ammonites were extinct cephalopods related to squid, cuttlefish, and octopuses. Their chambered shells and striking ribbed ornamentation make them some of the most recognizable fossils in the world, prized both for their scientific importance and their visual appeal. This specimen is a carefully chosen piece, photographed clearly to show the exact fossil you will receive, with a 1 cm scale cube for sizing reference.

Geological Context – Bajocian Stage of the Jurassic

The Bajocian Stage, part of the Middle Jurassic, dates to approximately 170–168 million years ago. This was a dynamic time in Earth’s history when ammonites thrived in warm, shallow seas that covered much of present-day Europe. The region of Calvados in Normandy is renowned for its fossiliferous limestone beds, which preserve an extraordinary diversity of marine invertebrates.

These deposits formed in a shallow marine environment rich in nutrients, where ammonites such as Caumatosphinctes polygyralis flourished. The fine-grained sediments of these Jurassic seas allowed for excellent preservation, often capturing intricate shell details that highlight the morphology of each species.

Species Profile – Caumatosphinctes polygyralis

The species Caumatosphinctes polygyralis belongs to the order Ammonitida, within the family Perisphinctidae, a group noted for its strongly ribbed shells. Ammonites in this family were free-swimming predators that played a crucial role in Jurassic marine ecosystems.

Key morphological features of Caumatosphinctes polygyralis include:

• Involute shell coiling, with later whorls overlapping earlier ones.
• Sharp, continuous ribbing running across the shell flanks, often branching as it approaches the outer whorl.
• A relatively compressed whorl cross-section, giving it a distinctive hydrodynamic shape.
• Complex suture lines characteristic of advanced ammonites, providing strength and structural adaptation.

These features make this species highly distinctive among Bajocian ammonites and valuable for both collectors and scientific study.

Scientific and Collectible Importance

Ammonites such as Caumatosphinctes polygyralis are vital to paleontologists because they serve as index fossils, helping to date and correlate rock layers across regions. Their rapid evolution and widespread distribution make them indispensable tools for reconstructing Earth’s geological past.

For collectors, this ammonite fossil offers both aesthetic beauty and historical significance. Its ribbed structure and well-preserved details demonstrate the complexity of Jurassic ammonites, while its provenance from Calvados, France, adds additional value due to the region’s global importance in paleontology.

100% Genuine with Certificate of Authenticity

Every fossil we sell is guaranteed 100% genuine and is supplied with a Certificate of Authenticity, providing complete assurance of its authenticity and provenance.

A Unique Collector’s Fossil

This Caumatosphinctes polygyralis ammonite fossil from Calvados, France is not only a scientifically valuable specimen but also a striking natural history display piece. Its combination of age, beauty, and detailed preservation makes it an exceptional addition to any fossil collection, educational resource, or natural history display.

Scale Rule Squares / Cube = 1 cm. Please see listing photos for the full sizing of this exact specimen.