Otoceras sakzei Ammonoid Fossil Bajocian Jurassic Dorset UK Genuine COA – Polygyralis Subzone Oborne Wood Quarry Specimen

Description

Genuine Otoceras sakzei Ammonoid Fossil

This carefully selected fossil is an authentic specimen of Otoceras sakzei, an extinct marine ammonoid preserved within rock of the Inferior Oolite Group. It originates from Oborne Wood Quarry near Sherborne in Dorset, England, a classic British Middle Jurassic fossil locality known for its richly fossiliferous limestone beds.

Dating from the Bajocian Stage of the Middle Jurassic, this fossil represents a marine animal that lived approximately 168–170 million years ago. More precisely, the specimen is recorded from the Polygyralis Subzone, giving it an important stratigraphical context within the Jurassic succession of southern England.

The photographs show the actual fossil specimen you will receive. Full sizing and scale information can be seen in the accompanying photographs.

Middle Jurassic Fossil from Dorset

During the Bajocian, the region that is now Dorset lay beneath a warm, shallow sea. Sediment accumulated across the seabed and eventually formed the limestones, marls and oolitic rocks collectively known as the Inferior Oolite Group. These rocks preserve a diverse marine fauna that can include ammonoids, belemnites, brachiopods, bivalves, gastropods, echinoids and other invertebrates.

Oolitic limestone formed in warm, agitated marine water where small, rounded carbonate grains developed through the repeated deposition of calcium carbonate around tiny particles. The changing sea level, water depth, sediment supply and seabed conditions created a complex sequence of fossil-bearing horizons. Ammonoids are particularly valuable within these deposits because individual species evolved rapidly and became widely distributed, allowing palaeontologists to correlate rocks of similar age between different locations.

The Polygyralis Subzone is one of these carefully recognised biostratigraphical intervals. Recording the subzone significantly improves the scientific and collectable interest of the specimen by placing it within a relatively narrow section of Middle Jurassic geological time.

Extinct Marine Cephalopod

Ammonoids were shelled cephalopods related to living squid, cuttlefish, octopuses and nautiluses. They possessed an externally coiled shell divided internally into a sequence of chambers. The animal occupied the final and largest chamber, while the older chambers formed the phragmocone.

A narrow connecting structure called the siphuncle passed through the chambers and helped regulate buoyancy. This chambered construction allowed ammonoids to move through the Jurassic seas while maintaining control over their position in the water. Depending on the species and growth stage, ammonoids may have lived close to the seabed or travelled through the open water in search of prey.

The shell form, degree of coiling, whorl proportions, ornament and suture pattern are among the features used by specialists when identifying ammonoid fossils. Preservation varies naturally between specimens, and surviving details can include portions of the coiled whorls, ribbing, shell contours, internal chambers or the surrounding Jurassic matrix.

Oborne Wood Quarry Fossil Locality

Oborne Wood Quarry is an important Inferior Oolite locality in Dorset and forms part of the historically significant Jurassic geology surrounding Sherborne. Fossils from this area have long been studied because the exposed beds provide detailed evidence of changing marine environments and ammonoid evolution during the Bajocian.

A correctly localised specimen such as this is more than an attractive natural object. It is a physical record of an extinct animal, the ancient sea in which it lived and the geological processes that preserved its remains for millions of years. Its combination of named species, recognised geological group, precise stage, subzone and British locality makes it particularly suitable for an ammonite collection, educational display, geological study cabinet or natural-history collection.

Actual Specimen with Certificate of Authenticity

This is a genuine fossil and not a cast, replica or reproduction. It has been individually chosen for its natural character and collectable appeal. As with all authentic fossils, variations in colour, texture, matrix, completeness and surface detail are part of the specimen’s geological history.

The photograph shows the exact Otoceras sakzei ammonoid fossil you will receive. Full sizing is shown in the photographs.

A generic Certificate of Authenticity card is included with a lifetime guarantee of authenticity, providing lasting confidence in the genuine nature of the specimen.