Rare Gleviceras subguibalianum Ammonite Fossil Genuine Jurassic Upper Pliensbachian St Peters Field Radstock UK with COA

Description

100% Genuine Rare Gleviceras subguibalianum Ammonite Fossil

This listing is for a rare Gleviceras subguibalianum ammonite fossil from the Upper Pliensbachian stage of the Jurassic period, collected at St Peters Field, Radstock, United Kingdom. The exact specimen pictured is the one you will receive, with a 1cm scale cube included for precise size reference. All of our fossils are 100% genuine and are supplied with a Certificate of Authenticity, ensuring its provenance and authenticity.

Geological Background – Upper Pliensbachian, Jurassic

This ammonite originates from the Upper Pliensbachian stage of the Early Jurassic, dating to around 185 million years ago. At this time, southern Britain was covered by shallow epicontinental seas, part of a marine system that supported diverse ecosystems of ammonites, marine reptiles, and invertebrates. The sediments laid down in these seas form the famous Lower Lias sequence, a globally important unit in Jurassic stratigraphy.

The locality of St Peters Field, Radstock (Somerset, UK) is well-known among paleontologists and collectors for its ammonite-bearing beds. These deposits belong to the Spinatum Zone, an ammonite biozone of the Upper Pliensbachian that has long been used for biostratigraphic correlation across Europe. Fossils from this site are relatively rare, especially well-preserved specimens of Gleviceras.

Fossil Type and Species – Gleviceras subguibalianum

Gleviceras subguibalianum is an extinct ammonite species belonging to the order Ammonitida, superfamily Hildoceratoidea, and family Hildoceratidae. Gleviceras is distinguished by its compressed, discoidal shell and fine ribbing, features that make it a particularly elegant ammonite. The genus is significant for its role as a biostratigraphic marker in the Pliensbachian stage.

Ammonites like Gleviceras were nektonic predators, capable of active swimming and feeding on smaller marine organisms. Their chambered shells provided buoyancy regulation, while their streamlined form suggests they were adapted to fast movement in open waters.

Morphology and Distinguishing Features

The shell of Gleviceras subguibalianum is strongly compressed and discoidal, with an evolute to subinvolute coiling style that leaves inner whorls visible. The flanks are generally flat with fine, regular ribbing that runs smoothly towards the ventrolateral margins. The venter (outer edge of the whorl) is typically sharp, often keeled, reflecting adaptations for hydrodynamic efficiency.

Sutures are complex, with highly folded lobes and saddles typical of the Hildoceratidae family. This delicate ribbing and compressed form distinguish Gleviceras from other ammonites of the Spinatum Zone, making it easily identifiable for both paleontologists and collectors.

Biozone and Scientific Importance

Gleviceras subguibalianum is a defining species within the Spinatum Zone of the Upper Pliensbachian, and it plays an important role in ammonite biostratigraphy. Its restricted stratigraphic distribution makes it a reliable index fossil for dating marine deposits of this age.

The species contributes to our understanding of ammonite evolution during the Pliensbachian and provides insight into paleoecological conditions in the Early Jurassic seas of Britain. As a rare ammonite in UK deposits, specimens such as this carry significant scientific as well as collector value.

Collectors and Enthusiasts

For fossil collectors, a Gleviceras subguibalianum ammonite fossil from Radstock represents an exceptional specimen. Its rarity, elegant morphology, and association with a key stratigraphic zone make it a prized addition to any Jurassic fossil collection. With its strong provenance from St Peters Field, it is both scientifically valuable and visually striking, suitable for advanced collectors and those with a keen interest in Jurassic ammonites.

Why This Specimen is Unique

• Rare Gleviceras subguibalianum ammonite fossil
• From the Upper Pliensbachian, Spinatum Zone (~185 million years old)
• Collected at St Peters Field, Radstock, United Kingdom
• Belongs to the family Hildoceratidae, order Ammonitida
• Supplied with a Certificate of Authenticity
• Exact specimen shown in the photo will be sent
• Includes a 1cm scale cube for accurate size reference

This rare Gleviceras subguibalianum ammonite fossil is an outstanding specimen from the Upper Pliensbachian deposits of Radstock. With its fine ribbing, compressed shell, and rarity in British collections, it is a scientifically important and aesthetically beautiful example of Early Jurassic ammonite evolution.