Description
Prososphinctes mazoricus Ammonite Fossil – Genuine Upper Jurassic Specimen
This is a genuine Prososphinctes mazoricus ammonite fossil from Normandy, France. Dating to the Upper Jurassic, Lower Oxfordian stage, this specimen represents a collectable marine cephalopod from the ancient Jurassic seas of Europe. Prososphinctes is a Jurassic ammonite genus associated with perisphinctid ammonite faunas, a highly important group for understanding ammonite evolution, shell ornamentation, and Jurassic biostratigraphy.
This fossil is a carefully chosen specimen, with the photograph showing the actual fossil you will receive. It also includes a Certificate of Authenticity lifetime guarantee generic card, making it an excellent choice for fossil collectors, geology students, natural history displays, educational collections, and anyone interested in genuine Jurassic ammonites from France.
Geology, Age and Location
This ammonite comes from Normandy, France, a region well known for its Jurassic marine fossil deposits. The specimen is Lower Oxfordian in age, placing it in the early part of the Upper Jurassic, approximately 164 to 160 million years ago. During this time, much of western Europe was covered by warm, shallow to moderately deep epicontinental seas. These seas supported a rich marine ecosystem filled with ammonites, belemnites, nautiloids, bivalves, brachiopods, gastropods, echinoids, crinoids, corals, fish, and marine reptiles.
The Oxfordian stage is especially important in Jurassic geology because ammonites were abundant, diverse, and rapidly evolving. Their shells are often used by palaeontologists to identify and correlate rock layers, making Oxfordian ammonites valuable not only as display fossils but also as markers of geological time. A genuine ammonite from Normandy therefore has strong scientific, educational, and collector interest.
Fossil Type and Species
Prososphinctes mazoricus is an ammonite, an extinct marine cephalopod related to modern squid, cuttlefish, octopus, and nautilus. Ammonites had chambered shells divided internally by septa. The living animal occupied the final outer body chamber, while the earlier chambers helped regulate buoyancy as the animal moved through the water column.
Prososphinctes is generally associated with the ammonite order Ammonitida and the superfamily Perisphinctoidea, one of the most characteristic ammonite groups of the Jurassic Period. Perisphinctid ammonites are often recognised for their coiled shells, visible umbilicus, and ribbed ornamentation. These features make them attractive to collectors and useful for studying variation between Jurassic ammonite species.
Morphology and Collector Appeal
Prososphinctes ammonites typically display the classic planispiral ammonite form, with the shell coiled in a flat spiral. Depending on the specimen’s preservation and growth stage, examples may show rounded to moderately compressed whorls, a visible umbilicus, ribbed ornamentation, and natural internal mould detail. The ribs may pass across the flanks of the shell and can sometimes divide or change strength as the animal grew, reflecting the growth pattern and shell structure of the ammonite.
This type of Jurassic ammonite is popular with collectors because it combines strong visual appeal with clear palaeontological significance. The natural spiral form is instantly recognisable, while the ribbing and whorl shape provide a direct link to the animal’s life and growth in the Jurassic sea. Even where some surface detail is naturally worn or preserved as an internal mould, the specimen remains an authentic and attractive example of ancient marine life.
Depositional Environment
During the Lower Oxfordian, Normandy lay within a broad Jurassic marine setting connected to the warm seas of western Europe. Ammonites such as Prososphinctes lived in the water column, using their chambered shells for buoyancy while feeding as active marine predators or scavengers. They shared these seas with belemnites, nautiloids, bivalves, brachiopods, echinoids, fish, and marine reptiles, forming part of a complex and diverse ecosystem.
After death, the ammonite shell could settle onto the seabed and become buried by sediment. Over millions of years, mineralisation, compaction, and geological change preserved the shell or internal mould as a fossil. This process created the specimen seen today, a tangible record of a vanished Jurassic sea that existed long before humans and modern landscapes.
Authenticity and Display
All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. This Prososphinctes mazoricus ammonite fossil is supplied with a lifetime guarantee generic COA card for confidence and peace of mind.
Full sizing: please see photo.
The fossil shown in the photograph is the actual specimen you will receive. This genuine Lower Oxfordian Prososphinctes mazoricus ammonite from Normandy, France is a superb addition to a fossil collection, natural history cabinet, geology teaching set, Jurassic display, or collection of genuine marine cephalopod fossils.
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