Oppelia subradiata Fossil Ammonite Bajocian Jurassic France Genuine Specimen from Calvados

Description

This listing features a fine Oppelia subradiata ammonite fossil, dating from the Bajocian stage of the Middle Jurassic Period, approximately 170–168 million years ago. Discovered in the well-known fossil beds of Calvados, Normandy, France, this specimen represents one of the important index ammonites of the Jurassic, widely used in biostratigraphy and recognised for its distinctive morphology.

All of our fossils are 100% genuine specimens and supplied with a Certificate of Authenticity. The photographs show the exact fossil you will receive, with a 1 cm scale cube and rule squares provided for accurate sizing.

Geological Context and Age

This ammonite comes from the Bajocian stage, a subdivision of the Middle Jurassic, during which Europe was largely submerged beneath shallow tropical seas linked to the Tethys Ocean. The Calvados region of Normandy is particularly renowned for its Jurassic exposures, which have yielded beautifully preserved ammonites and other marine fossils.

The Bajocian deposits of Normandy are part of the Inferior Oolite Group, which formed in warm, carbonate-rich seas teeming with marine life. The ammonites preserved in these rocks provide invaluable information for biostratigraphic zoning, helping geologists correlate rock layers across Europe. Oppelia subradiata is among the key species used to define ammonite zones within this stage.

Morphology and Distinctive Features

Oppelia subradiata belongs to the family Oppeliidae, within the superfamily Haploceratoidea of the order Ammonitida. This species is distinguished by its discoidal, compressed shell with fine ribbing that extends across the flanks and often weakens towards the venter. The shell is strongly involute, meaning earlier whorls are concealed by the outer coils.

This specimen shows the diagnostic features of Oppelia subradiata: smooth to finely striated sides, a narrow rounded venter, and sutures with moderate complexity. Its elegant form suggests a hydrodynamic shell well adapted to a nektonic lifestyle, enabling the ammonite to move actively through the Jurassic seas as a predator of small crustaceans and fish.

Scientific Importance

Oppelia subradiata is of considerable importance in Jurassic stratigraphy. As a species with a well-defined stratigraphic range, it serves as an excellent index fossil for the Bajocian stage. Its widespread distribution across Europe and precise evolutionary timeframe make it invaluable for dating and correlating Middle Jurassic sediments.

This ammonite also contributes to the understanding of the evolution of the Oppeliidae family, one of the most significant ammonite groups of the Jurassic. Studying fossils like Oppelia subradiata helps palaeontologists reconstruct evolutionary trends, palaeobiogeography, and marine ecological conditions during the Middle Jurassic.

Collector and Display Value

This Oppelia subradiata ammonite fossil from Calvados, France, is both scientifically important and visually appealing. Its elegant, compressed form makes it an excellent display specimen, while its role as a stratigraphically significant ammonite adds considerable value to any serious fossil collection.

Collectors of Jurassic ammonites, French fossils, or stratigraphically important specimens will find this ammonite a particularly desirable addition. Its provenance from the classic Jurassic localities of Normandy further enhances its appeal, connecting it to a rich tradition of palaeontological study in the region.

Your Guarantee of Authenticity

• 100% genuine Oppelia subradiata ammonite fossil from Calvados, Normandy, France
• Geological age: Bajocian stage, Middle Jurassic (approx. 170–168 million years old)
• From the Inferior Oolite Group, classic Jurassic deposits
• Supplied with a Certificate of Authenticity
• Exact specimen shown in photographs (not a stock image)
• Scale cube and rule squares = 1 cm (see photos for precise sizing)

This Oppelia subradiata ammonite fossil is a scientifically significant and beautifully preserved specimen from the Bajocian deposits of Calvados. With its elegant form, guaranteed authenticity, and historical provenance, it is an outstanding addition to any fossil collection.