RARE Double Parabolina spinulosa Trilobite Fossil with Positive & Negative – Upper Cambrian – Craig-y-Dinas, Wales – Certified

RARE Double Parabolina spinulosa Trilobite Fossil with Positive & Negative –
Upper Cambrian, Merioneth Series – Cwmhesgyn Formation – Craig-y-Dinas, Wales

This exceptional specimen is a RARE paired positive and negative impression fossil of the Upper Cambrian trilobite species Parabolina spinulosa, discovered in the Cwmhesgyn Formation, part of the Merioneth Series, at Craig-y-Dinas, Wales. The matched fossil halves beautifully preserve this extinct arthropod in full relief and counterpart, providing a scientifically valuable and visually striking piece.

FOSSIL OVERVIEW:

• Species: Parabolina spinulosa
• Type: Double fossil (positive impression & negative counterpart)
• Geological Formation: Cwmhesgyn Formation
• Stratigraphy: Merioneth Series (Dolgellian subdivision)
• Location: Craig-y-Dinas, Wales
• Geological Age: Upper Cambrian (Furongian, ~497–485 million years ago)
• Depositional Environment: Deep marine basinal sediments; fine-grained turbiditic mudstones and silty shales
• Lithology: Dark grey mudstone typical of distal slope environments

MORPHOLOGY & FEATURES:

Parabolina spinulosa is known for its relatively small size and streamlined body with the following key characteristics:

• Long, narrow glabella (central lobe of head)
• Faintly developed genal spines
• Distinct axial furrows
• Eleven thoracic segments with defined pleurae
• A semicircular pygidium with a spinose termination in some specimens

The double (mirror) impression in this specimen allows both surface and underside detail to be seen — making it particularly valuable for scientific comparison and educational use.

TAXONOMY & CLASSIFICATION:

• Phylum: Arthropoda
• Class: Trilobita
• Order: Ptychopariida
• Family: Parabolinidae
• Genus: Parabolina
• Species: spinulosa
• Superfamily: Olenoidea
• Zone/Biozone: Parabolina spinulosa Biozone – an important Upper Cambrian biostratigraphic indicator
• Described By: Salter, mid-19th century (refined by later palaeontologists)

This species is widely used to define the P. spinulosa Biozone in British and European Upper Cambrian stratigraphy.

NOTABLE & SCIENTIFIC RELEVANCE:

• Important marker fossil in Upper Cambrian zonation
• Exceptional dual preservation (positive/negative)
• Sourced from a classic Welsh trilobite site
• Adds strong visual and comparative value to any collection
• Ideal for education, display, and palaeontological reference
• Includes full Certificate of Authenticity

Specimen Information:

• Condition: Excellent preservation with clear morphological detail on both positive and negative halves
• Size Reference: Scale rule squares/cube = 1cm; please see full-size photo for dimensions
• What You See Is What You Get: Actual specimen is shown in photos
• Authenticity Guaranteed: All fossils sold are 100% genuine and include documentation

Summary:

This is a superb and rare double fossil of the trilobite Parabolina spinulosa from the Upper Cambrian Cwmhesgyn Formation of Craig-y-Dinas, Wales. It offers a unique mirror image preservation (positive and negative), a key stratigraphic species, and scientific relevance — perfect for collectors, educators, and enthusiasts alike.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.