VERY RARE British Cambrian Trilobite – Tomagnostus fissus – Menevian Series, Hicksii Biozone, Wales – Genuine with COA

Description

Extremely Rare British Cambrian Trilobite – Tomagnostus fissus

Species: Tomagnostus fissus

Geological Age: Middle Cambrian (~510 million years ago)

Formation: Menevian Series

Biozone: Hicksii Biozone

Location: Nine Wells, St David’s, Pembrokeshire, South Wales, United Kingdom

This is a very rare British trilobite fossil of the species Tomagnostus fissus, a member of the Agnostida order from the Middle Cambrian. Sourced from the historic locality of Nine Wells, near St David’s in Pembrokeshire, this beautifully preserved specimen dates back over half a billion years, offering a tangible piece of early Paleozoic life.

Scientific Classification

• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Trilobita
• Order: Agnostida
• Superfamily: Agnostoidea
• Family: Agnostidae
• Genus: Tomagnostus
• Species: fissus

Originally described by Salter (1864) and later formally assigned as Tomagnostus fissus, this species plays a vital role in the biostratigraphic division of the Cambrian, especially within the Hicksii Biozone of the Menevian Series.

Geological & Depositional Context

• Stratigraphy: Menevian Series – Middle Cambrian
• Biozone: Hicksii Biozone – Defined by Paradoxides hicksi, contemporaneous with Tomagnostus fissus
• Depositional Environment: Fine-grained marine siliciclastic sediments, representing an offshore shelf to deep marine setting rich in early marine arthropod diversity
• Notable Features: Part of the classic British Cambrian sequence, the Menevian Series is world-renowned for its fossil-rich layers

Morphology & Preservation

• Agnostid Trilobite Morphology: Tomagnostus fissus features a cephalon and pygidium of nearly equal size (isopygous) with a smooth, unornamented exoskeleton.
• Two or three thoracic segments and a lack of visible eyes are diagnostic of Agnostids – adaptations likely linked to a pelagic lifestyle in deeper Cambrian seas.
• Specimen Detail: Fossil is preserved in a dark grey to olive shale matrix; see photo with 1cm scale cube for precise measurements. The fossil you see is the exact piece you will receive.

Provenance & Handling

This unique specimen was discovered at the famous Nine Wells site near St David’s, a globally significant fossil locality in Wales. It was carefully chosen for its quality and has been professionally cleaned and stabilized.

Genuine Specimen with Certificate

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity. The fossil you see in the photos is the actual one you will receive, not a stock image.

This is a rare opportunity to own a scientifically significant, investment-grade example of early arthropod evolution from a historic British Cambrian site.