Description
Authentic 4.5″ Fossil Ammonite from France
This listing is for a genuine 4.5″ fossil ammonite, Perisphinctes (Dichotomosphinctes) luciaeformis, originating from the Middle Oxfordian stage of the Jurassic Period, approximately 160–157 million years ago. Discovered in Deux Sèvres, France, this is a carefully selected specimen showcasing the ribbed and beautifully coiled shell structure characteristic of this species. The fossil pictured is the exact one you will receive. Scale rule squares / cube = 1 cm – please see the images for full sizing details. Every fossil we sell is 100% genuine and is supplied with a Certificate of Authenticity for complete confidence.
Geological Context: Middle Oxfordian, Jurassic
This specimen comes from the Middle Oxfordian stage of the Late Jurassic, a time when ammonites thrived in warm epicontinental seas. The Oxfordian is one of the most important intervals for ammonite biostratigraphy, with numerous species used to define biozones across Europe. The sedimentary deposits in the Deux Sèvres region of France represent shallow marine environments where fine clays and limestones accumulated, preserving ammonites in remarkable detail.
The Oxfordian stage forms part of the Upper Jurassic system, renowned for its rich diversity of ammonites. These deposits serve as key reference points in global stratigraphy, making fossils such as this one significant both scientifically and historically.
The Species: Perisphinctes (Dichotomosphinctes) luciaeformis
Perisphinctes (Dichotomosphinctes) luciaeformis is a species of ammonite within the order Ammonitida, superfamily Perisphinctoidea, and family Perisphinctidae. This species is well known for its elegant, planispiral coiling and strong ribbing that often bifurcates (splits) across the whorls, giving it a distinctive and highly recognisable appearance.
Ammonites like P. luciaeformis were free-swimming cephalopods, related to modern squid and octopuses, and are thought to have been active predators in Jurassic seas. Their shells not only provided buoyancy but also protection, with ribbing and ornamentation likely reinforcing the structure against predation and pressure.
This species is used as an index fossil for the Oxfordian stage, particularly in defining biostratigraphic zones in Western Europe. Its abundance and distinct morphology make it crucial for correlating Jurassic rock sequences across different regions.
Morphological and Scientific Features
- Order: Ammonitida
- Superfamily: Perisphinctoidea
- Family: Perisphinctidae
- Genus and Species: Perisphinctes (Dichotomosphinctes) luciaeformis
- Geological Stage: Middle Oxfordian, Upper Jurassic (c. 160–157 Ma)
- Locality: Deux Sèvres, France
- Size: 4.5 inches (scale cube = 1 cm shown in photos)
- Shell Traits: Strong, bifurcating ribs, planispiral coiling, compressed whorls, diagnostic ornamentation
- Scientific Significance: Key index fossil for Oxfordian biozones
The ribbing and bifurcation patterns of Perisphinctes luciaeformis not only provide aesthetic appeal but also serve as essential diagnostic traits in ammonite taxonomy.
Collector and Display Value
Ammonites are among the most iconic and collectible fossils, and specimens of Perisphinctes luciaeformis from France are especially prized. Their scientific importance as biostratigraphic markers, combined with their elegant ribbed morphology, makes them desirable for both researchers and collectors.
This 4.5″ specimen is an excellent display fossil, combining size, preservation, and scientific relevance. Its provenance from the Oxfordian of Deux Sèvres ensures that it represents a significant period in Earth’s history, when ammonites were at the height of their evolutionary diversity.
Every fossil is individually selected and supplied with a Certificate of Authenticity, guaranteeing that your purchase is a genuine specimen. This ammonite provides not only a fascinating link to the Jurassic seas but also a striking natural piece for collectors, educators, or as a unique display item.
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