British Trilobite Ogyginus Partial Fossil with Stand – Llanvirn Series, Ordovician, Upper Gilwern Quarry, Wales, UK

Authentic British Trilobite (Ogyginus) Partial Fossil from Wales

This rare British Trilobite (Ogyginus) Partial Fossil with Stand originates from the Upper Gilwern Quarry in Wales, UK, dating to the Llanvirn Series of the Ordovician Period—approximately 465 million years ago. It represents an exceptional specimen of one of Britain’s most recognisable trilobites, discovered by our own field team, Alister and Alison, on 2 April 2024, and later cleaned, prepped, and treated by Alison with expert precision.

Each specimen is presented on a custom display stand, allowing you to appreciate its fine details and natural geological context. The photo shows the exact fossil you will receive, complete with a 1 cm scale cube for accurate size reference. Every piece includes a Certificate of Authenticity, confirming its genuine origin and professional preparation.

Geological and Palaeontological Background

The Llanvirn Series represents a key subdivision of the Ordovician Period, approximately 470–458 million years ago, during which time much of present-day Wales was submerged beneath warm, shallow seas. The region was part of the ancient continent Avalonia, located in the southern hemisphere. Within this marine environment, trilobites such as Ogyginus thrived on the sea floor alongside graptolites, brachiopods, and cephalopods.

This particular specimen was collected from the Upper Gilwern Quarry, which exposes fossil-rich beds of the Bala Group, a sequence of fine-grained mudstones and siltstones deposited in an offshore marine environment. These sediments preserve a wealth of marine life, fossilised in exquisite detail due to rapid burial in low-oxygen conditions that inhibited decay.

The Llanvirn rocks form part of the Caradoc–Llanvirn succession, long studied for their biostratigraphic significance. The fossil content helps geologists correlate Ordovician strata across Europe, offering insights into ancient biodiversity and palaeogeography.

Taxonomy and Classification

• Phylum: Arthropoda

• Class: Trilobita

• Order: Asaphida

• Family: Asaphidae

• Genus: Ogyginus (Murchison, 1839)

• Geological Age: Llanvirn Series, Middle Ordovician (~465 million years)

• Locality: Upper Gilwern Quarry, Wales, UK

The genus Ogyginus was first described by Sir Roderick Murchison in 1839, a pioneering geologist who named the Silurian and contributed extensively to British stratigraphy. It remains a type genus for Ordovician trilobites in the region, often used as a biostratigraphic marker within the Asaphid trilobite biozone.

Morphology and Preservation

The Ogyginus trilobite is characterised by its broad, smooth cephalon (head shield), distinct glabella (central lobe), and large, rounded pygidium (tail shield). The species lacks eyes, an adaptation suggesting a benthic lifestyle in deeper, low-light marine environments. Its exoskeleton is typically thin but preserves well in fine mudstone, showing detailed surface features such as faint segmental ridges and shallow furrows.

This partial fossil displays the cephalon and thoracic segments in remarkable condition, allowing study of its structural form. The preservation highlights subtle anatomical features that define Ogyginus, including its smooth surface and characteristic shape. The specimen’s natural matrix offers excellent contrast, enhancing the fossil’s visual and scientific appeal.

Depositional Environment and Palaeoecology

During the Middle Ordovician, the seas covering Avalonia were rich in planktonic life, sustaining diverse benthic ecosystems. Trilobites like Ogyginus were epibenthic detritivores, feeding on organic matter within fine seafloor sediments. Their streamlined bodies and lack of eyes suggest adaptation to quiet, deeper marine settings where sunlight was scarce.

The fossil’s preservation within laminated mudstones indicates rapid burial in anoxic sediments, preventing scavenging and decay. Such conditions frequently produced complete or near-complete trilobite fossils, making sites like Upper Gilwern Quarry invaluable for palaeontological study.

Collector and Display Significance

This Ogyginus trilobite fossil from Wales is a scientifically important and visually striking specimen, representing an authentic piece of British geological heritage. Its discovery, preparation, and documentation by our field team ensure complete provenance and quality assurance. Mounted on a display stand, it serves as both a museum-quality educational specimen and a decorative centrepiece for fossil enthusiasts and collectors alike.

All of our Fossils are 100% Genuine Specimens and come with a Certificate of Authenticity.
Scale cube = 1 cm – for full sizing, please refer to the photos.