Fossil Ammonite Amoeboceras serratum Jurassic Oxfordian Ampthill Clay Oxford UK

Description

Genuine Jurassic Ammonite – Amoeboceras serratum

This listing features a rare fossil ammonite of the species Amoeboceras serratum, preserved within the Ampthill Clay Formation of Oxford, United Kingdom. Dating from the Oxfordian stage of the Late Jurassic (~160 million years ago), this ammonite is a scientifically significant specimen with striking ribbed ornamentation and excellent preservation. As with all of our fossils, the exact specimen photographed is the one you will receive, and it comes supplied with a Certificate of Authenticity for complete assurance.

Geological Setting – The Ampthill Clay

The Ampthill Clay Formation is a Late Jurassic marine deposit found across parts of Oxfordshire and southern England. Belonging to the Oxfordian stage of the Jurassic system, these dark clays and marls were laid down in shallow, warm epicontinental seas that once covered large swathes of Britain. Fossil preservation within this formation is excellent, with ammonites, bivalves, brachiopods, and occasional vertebrate remains recorded.

The presence of Amoeboceras serratum within these deposits is of particular importance for biostratigraphy, as ammonites of the genus Amoeboceras serve as classic index fossils for the Oxfordian. Their restricted time range makes them vital for correlating rock layers across Europe.

Scientific Classification

• Kingdom: Animalia
• Phylum: Mollusca
• Class: Cephalopoda
• Order: Ammonitida
• Superfamily: Perisphinctoidea
• Family: Cardioceratidae
• Genus: Amoeboceras
• Species: Amoeboceras serratum

This placement highlights its connection to other strongly ribbed ammonites of the Cardioceratidae family, which were common predators and index fossils during the Oxfordian stage.

Morphology and Distinctive Features

The species Amoeboceras serratum can be recognised by:

• Densely ribbed shell with sharp, well-defined ribs running across the whorls.
• Strong keel development, a feature common to many Oxfordian ammonites.
• Compressed whorl section, giving the fossil a slightly discoidal appearance.
• Fine suture lines with complex lobes and saddles, typical of the Cardioceratidae.

These features not only make the fossil aesthetically striking but also serve as key identifiers for paleontologists when distinguishing between closely related Oxfordian ammonite taxa.

Palaeoecology – Life in the Oxfordian Seas

Amoeboceras serratum was a nektonic carnivorous cephalopod, actively swimming in the Jurassic seas of Europe. Like modern squids and nautiloids, it likely fed on small crustaceans, juvenile fish, and planktonic organisms. Its ribbed shell structure would have offered strength and hydrodynamic stability, while the internal chambers controlled buoyancy.

The species is significant not only as a predator in its ecosystem but also as a tool for reconstructing Jurassic palaeoenvironments. Its abundance and stratigraphic precision make it a cornerstone of Jurassic geological studies.

Collector and Scientific Value

This ammonite fossil is of high value both to private collectors and to those with an academic interest in Jurassic stratigraphy. Its well-defined ribbing and stratigraphic importance ensure that it stands out as both a display piece and a scientifically meaningful specimen. Fossils from Oxfordshire’s classic Oxfordian deposits remain highly sought after, and this example of Amoeboceras serratum exemplifies the rich paleontological heritage of the region.

Provenance and Guarantee

• Species: Amoeboceras serratum
• Age: Jurassic, Oxfordian stage (~160 million years old)
• Formation: Ampthill Clay Formation
• Locality: Oxford, Oxfordshire, United Kingdom

This carefully selected fossil is guaranteed to be authentic, photographed as the exact specimen for sale, and supplied with a Certificate of Authenticity.

This Jurassic ammonite fossil of Amoeboceras serratum is an exceptional addition to any fossil collection, combining striking natural beauty, scientific significance, and outstanding provenance from the historic Oxfordshire deposits.