Description
Authentic Bajocian Ammonite Fossil
This listing presents a Prorsisphinctes pseudomartinsi Ammonite Fossil from the Bajocian Stage of the Middle Jurassic, unearthed in Evrecy, Calvados, Normandy, France. Ammonites were marine cephalopods related to modern squids and octopuses, and they remain among the most iconic and scientifically valuable fossils in paleontology. This specimen displays the intricate ribbing and coiled structure typical of Bajocian ammonites and has been carefully selected for its scientific value and aesthetic preservation. The accompanying photographs show the exact fossil you will receive, with a 1 cm scale cube included for accurate sizing.
Geological Context – Bajocian Stage
The Bajocian Stage is part of the Middle Jurassic Period, dating to around 170–168 million years ago. During this time, shallow tropical seas covered much of Europe, including the Normandy region of France, which is now globally recognised for its rich fossil beds. The Evrecy deposits are especially significant, preserving an extraordinary diversity of ammonite species and serving as important reference points in Jurassic stratigraphy.
The depositional environment of Calvados was a shallow marine platform dominated by carbonate-rich sediments. These calm seabeds allowed for exceptional fossilisation, often preserving ammonites with remarkable clarity, making them indispensable for biostratigraphic studies and highly desirable to collectors.
Species Profile – Prorsisphinctes pseudomartinsi
The species Prorsisphinctes pseudomartinsi belongs to the order Ammonitida, within the family Perisphinctidae. Ammonites of this family are known for their strong ribbing and rapid evolutionary turnover, making them crucial as index fossils for correlating rock layers of Bajocian age across Europe.
Key features of Prorsisphinctes pseudomartinsi include:
- Planispiral coiling, with tightly wound whorls forming a symmetrical shell.
- Prominent radial ribbing, often bifurcating as it extends across the flanks toward the outer whorl.
- A compressed shell form, giving it a hydrodynamic shape well-suited to active swimming in open marine environments.
- Distinctive suture patterns with complex lobes and saddles, a hallmark of ammonites that provided both structural strength and evolutionary refinement.
This species, like others of its genus, played an important ecological role as an active nektonic predator in Jurassic seas.
Scientific and Collectible Importance
Prorsisphinctes pseudomartinsi is more than a fossil; it is a window into the Jurassic seas. Its clearly defined morphology makes it valuable to paleontologists for identifying biozones within the Bajocian, while its aesthetic ribbed ornamentation enhances its desirability for collectors. Fossils from Evrecy, Calvados, are especially sought after due to the region’s renown as one of the richest ammonite-bearing localities in France.
Genuine Fossil with Certificate of Authenticity
As with all of our specimens, this ammonite fossil is 100% genuine and comes with a Certificate of Authenticity, ensuring complete provenance and verification for collectors, educators, and enthusiasts.
A Unique Addition to Any Collection
This Prorsisphinctes pseudomartinsi ammonite fossil from Evrecy, Calvados, France combines historical importance, geological context, and natural beauty. Its distinct ribbed features and Jurassic age make it an extraordinary addition to fossil collections, natural history displays, or as a gift for those passionate about Earth’s deep past.
Scale Rule Squares / Cube = 1 cm. Please refer to listing photos for the full sizing of this exact specimen.
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