Rare Bajocisphinctes ultimum Ammonite Fossil, Upper Bajocian Stage Jurassic, Calvados Region France

Description

Authentic Ammonite Fossil from the Jurassic of France

This listing presents a Bajocisphinctes ultimum ammonite fossil from the Upper Bajocian stage of the Middle Jurassic, discovered in the classic fossiliferous deposits of Calvados, Normandy, France. This remarkable specimen is a fine example of a Jurassic ammonite, offering both scientific and aesthetic appeal. Each piece is 100% genuine and comes with a Certificate of Authenticity. The photos display the exact specimen available, with a 1 cm scale cube included for accurate sizing.

Geological Context

The Bajocian stage (approximately 170–168 million years ago) is an interval within the Middle Jurassic characterised by widespread shallow marine environments across Europe. The Calvados region of Normandy is a particularly well-known locality for Bajocian ammonites, preserving them in exceptional detail within its marl and limestone strata.

During this time, the seas were rich in ammonites, bivalves, brachiopods, and marine reptiles, providing a vibrant and biodiverse ecosystem. Fossils such as this are essential for reconstructing ancient paleoenvironments and serve as key evidence in understanding the stratigraphy of Jurassic Europe.

Morphological Features of Bajocisphinctes ultimum

Bajocisphinctes ultimum, a member of the family Perisphinctidae within the superfamily Perisphinctoidea and the order Ammonitida, displays several characteristic traits:

• Planispiral shell form with moderately involute coiling, typical of perisphinctid ammonites.
• Prominent ribbing, often bifurcating as it extends across the flanks toward the outer whorl.
• A relatively wide umbilicus, giving the shell a balanced, open appearance.
• Growth lines and ribbing patterns that provide evidence of hydrodynamic adaptation in Jurassic seas.

These features not only assist in identifying the species but also highlight its evolutionary significance among Bajocian ammonites.

Scientific Importance

Ammonites such as Bajocisphinctes ultimum are important index fossils, meaning they are used by geologists and paleontologists to date and correlate rock layers worldwide. The Bajocian stage is well defined through ammonite biozones, and this species contributes to refining the understanding of Jurassic chronostratigraphy.

For collectors and researchers, owning such a specimen is both an aesthetic pleasure and a scientific opportunity. The ribbing, coiling, and preservation of this ammonite make it an excellent reference point for comparative study with related ammonite groups.

Collectible Value

This ammonite fossil is not only scientifically relevant but also visually striking, with its ribbed shell structure offering a dramatic display of Jurassic craftsmanship preserved in stone. Its origin from Calvados, Normandy, adds further prestige, as the region is celebrated for yielding some of the finest Bajocian ammonites in Europe.

Key Details of This Specimen

• Species: Bajocisphinctes ultimum
• Age: Upper Bajocian, Middle Jurassic (~170–168 million years old)
• Location: Calvados, Normandy, France
• Family: Perisphinctidae
• Superfamily: Perisphinctoidea
• Order: Ammonitida
• Authenticity: 100% genuine specimen with Certificate of Authenticity
• Photographs: Exact specimen shown, with 1 cm scale cube

A Timeless Fossil from France

This Bajocisphinctes ultimum ammonite offers collectors, educators, and fossil enthusiasts a rare chance to acquire a genuine piece of Middle Jurassic history. Its detailed ribbing and classic preservation reflect both the beauty and the scientific importance of ammonites from this key stage in Earth’s history.

Scale cube = 1 cm. Please see photographs for accurate specimen sizing.