Rare Pseudocadoceras boreale Ammonite Fossil Lower Callovian Jurassic Ashton Keynes Semmington United Kingdom

Description

Rare Ammonite from the Jurassic of Ashton Keynes

This listing offers a rare specimen of Pseudocadoceras boreale ammonite fossil, dating to the Lower Callovian stage of the Middle Jurassic, approximately 166–164 million years ago. Discovered in the historic fossil-rich beds of Ashton Keynes, Semmington, United Kingdom, this ammonite is an excellent example of a species seldom seen on the market. With its distinct morphology and preservation, it stands as both a scientifically valuable specimen and a striking collector’s piece. The exact fossil photographed is the one you will receive, shown with a 1 cm scale cube for reference. As with all of our fossils, it is supplied with a Certificate of Authenticity, guaranteeing its genuineness.

Geological Background

The Callovian stage represents an important interval within the Middle Jurassic, during which shallow epicontinental seas covered much of Europe. The sedimentary rocks in the Ashton Keynes and Semmington area capture a dynamic marine environment where ammonites flourished alongside marine reptiles, bivalves, and echinoids. These fossiliferous layers are globally important for their rich ammonite assemblages, which have been extensively studied to refine biostratigraphic frameworks.

Ammonites such as Pseudocadoceras boreale are considered index fossils, making them vital to stratigraphers in correlating rock sequences across regions. Their relatively rapid evolutionary turnover and wide geographic distribution give them an essential role in understanding the Jurassic seas.

Morphological Features of Pseudocadoceras boreale

This specimen exhibits the characteristic traits of the genus Pseudocadoceras, a member of the Stephanoceratoidea superfamily within the order Ammonitida. Defining features include:

• Robust, evolute shell with whorls visible from the umbilical side.
• Strong ribbing radiating from the umbilicus, creating a bold, sculptured appearance.
• Keel development along the venter, providing hydrodynamic stability during swimming.
• Distinctive suture patterns, a hallmark of ammonites, visible where the chamber walls met the shell.

These features not only highlight the evolutionary adaptations of Pseudocadoceras but also make the fossil visually striking for collectors.

Scientific and Historical Importance

Pseudocadoceras boreale has great scientific value due to its place within the Lower Callovian biozones. Ammonites of this genus are used to define and refine biochronological markers, helping geologists to accurately date marine sequences across Europe. Fossils from Ashton Keynes are especially prized for their clarity and stratigraphic significance, often serving as reference material in paleontological studies.

The historical importance of the Ashton Keynes region lies in its long-standing contributions to British paleontology. Many 19th and 20th-century geologists studied the area, adding to our collective understanding of Jurassic life.

Collector and Display Value

This fossil is not only scientifically significant but also aesthetically appealing. Its defined ribbing, rare provenance, and excellent preservation make it an ideal piece for both serious collectors and those seeking a unique natural display item. Unlike the more common ammonites of Dorset’s Lias or Charmouth’s pyritised specimens, Callovian ammonites from Gloucestershire and Wiltshire are considerably rarer, adding exclusivity to this piece.

Its preservation allows for close inspection of ammonite morphology, offering both educational and decorative value. It is a specimen equally at home in a private collection, a teaching collection, or as a natural centrepiece in a display.

Key Details

• Species: Pseudocadoceras boreale
• Age: Lower Callovian, Middle Jurassic (~166–164 million years old)
• Location: Ashton Keynes, Semmington, United Kingdom
• Order: Ammonitida
• Superfamily: Stephanoceratoidea
• Preservation: Strong ribbing, keel development, and morphological detail intact
• Authenticity: 100% genuine specimen with Certificate of Authenticity
• Scale cube: 1 cm (see photographs for accurate size reference)

This rare Pseudocadoceras boreale ammonite fossil from Ashton Keynes represents a remarkable opportunity to own a scarce Jurassic specimen that combines geological, scientific, and display value in one extraordinary fossil.

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