Description
Genuine Stereocidaris sceptrifera Echinoid Fossil
This carefully chosen fossil is a genuine specimen of Stereocidaris sceptrifera, an extinct regular echinoid, or sea urchin, from Saintonge in Charente-Maritime, south-western France. It dates from the Campanian Stage of the Upper Cretaceous and represents an animal that inhabited a warm European marine environment approximately 72–84 million years ago.
The specimen offers an attractive example of a classic Cretaceous cidaroid echinoid, a group recognised for its robust test, comparatively narrow ambulacral zones and prominent spine-bearing tubercles. Its identifiable species, French provenance and Upper Cretaceous age make it suitable for fossil collectors, geological displays, educational collections and natural-history enthusiasts.
The listing photographs show the actual fossil specimen you will receive. Please refer to the photographs for full sizing, scale, colour, shape, preservation and condition. Natural mineral staining, sediment, weathering, small fractures and variations in surface detail are authentic characteristics of a fossil that has undergone millions of years of burial and geological change.
Fossil Species and Scientific Classification
Stereocidaris sceptrifera belongs to the phylum Echinodermata, class Echinoidea and order Cidaroida. Cidaroids are an ancient lineage of regular sea urchins whose fossil record extends far back into geological history. Their distinctive skeletal construction differs in several important ways from that of many modern echinoids.
The fossilised shell of the animal is known as the test. It was formed from tightly interlocking calcite plates arranged in five ambulacral zones alternating with five broader interambulacral zones. This five-part arrangement is characteristic of echinoderms.
During life, the test was covered by movable spines attached to large circular tubercles. These spines helped defend the animal, supported movement across the seabed and assisted with interactions between the echinoid and the surrounding sediment.
Distinctive Stereocidaris Morphology
Stereocidaris sceptrifera typically possessed a rounded to slightly flattened test with radial symmetry. The upper and lower surfaces were organised around a vertical axis, with the mouth located on the underside and the apical system positioned at the top.
The interambulacral areas commonly carry large primary tubercles arranged in vertical rows. Each tubercle served as the attachment point for a major spine. Smaller secondary tubercles and granules occupied the spaces between the larger structures, supporting finer spines that helped protect the surface of the animal.
The ambulacral zones are narrower and contain paired pores. In life, soft tube feet extended through these openings. The tube feet assisted with locomotion, respiration, sensory functions and the handling of food.
Cidaroid spines were attached by flexible muscles and ligaments to the prominent tubercles. The largest spines were often robust and could differ significantly in form from the finer covering spines. After death, these spines usually detached from the test, which is why complete fossil cidaroids with their original spines in place are exceptionally uncommon.
Depending on preservation, this specimen may display primary tubercles, secondary granulation, ambulacral pore pairs, plate boundaries, the apical region or part of the opening that surrounded the mouth. The photographs provide the clearest guide to the exact morphological features retained on this individual fossil.
Campanian Upper Cretaceous Age
The Campanian is a major geological stage within the Upper Cretaceous. It followed the Santonian and preceded the Maastrichtian, representing a period when high sea levels covered extensive parts of Europe beneath shallow to moderately deep marine waters.
During the Campanian, the arrangement of continents was very different from today. The Atlantic Ocean was continuing to widen, and much of western Europe consisted of islands, shallow seas and submerged carbonate platforms.
Marine sediments accumulated across the region and preserved a diverse fossil record. Echinoids such as Stereocidaris sceptrifera lived alongside ammonites, bivalves, brachiopods, sponges, bryozoans, corals, crustaceans, fish and marine reptiles.
Fossils from Campanian deposits are scientifically valuable because they help palaeontologists reconstruct the changing marine ecosystems of the later Cretaceous and compare rock successions across France and neighbouring parts of Europe.
Geology of Saintonge and Charente-Maritime
Saintonge is a historic region centred largely within the modern department of Charente-Maritime in south-western France. The area is well known for extensive exposures of Mesozoic and younger sedimentary rocks, including marine limestones deposited during the Cretaceous.
The Campanian rocks of this region formed from sediment accumulating on the floor of a warm sea. Depending on the precise local bed, these deposits may include chalky limestone, fine-grained carbonate rock, marly limestone and other marine sediments rich in fossil remains.
Much of the carbonate material originated from the skeletal remains of microscopic plankton and larger marine organisms. Fine particles settled gradually through the water and accumulated as soft sediment on the seabed. Additional shell fragments, echinoid plates and other biological debris became incorporated into these deposits.
Over millions of years, burial compacted the sediment and circulating mineral-rich water cemented the particles together. This process transformed the original seabed mud into solid limestone while preserving the remains of animals such as Stereocidaris sceptrifera.
Ancient Marine Habitat
Stereocidaris sceptrifera was a benthic animal that lived on the seabed. Like other regular echinoids, it moved using a combination of tube feet and articulated spines.
The mouth was positioned centrally on the underside of the test. It contained a specialised feeding apparatus called Aristotle’s lantern, composed of hard calcareous elements and five teeth. This structure allowed the echinoid to scrape, bite and process food from the seabed.
Its diet may have included algae, microbial growth, organic debris and small encrusting organisms. As it moved across firm or partly sediment-covered surfaces, the spines provided support and protection while the tube feet maintained contact with the substrate.
The large primary spines of cidaroids also acted as an effective defence against predators. Smaller organisms could sometimes settle on or around the spines, turning the living echinoid into a small mobile habitat within the wider marine ecosystem.
Fossilisation and Natural Preservation
After death, the soft tissues decayed and the spines usually separated from the test. The test could then become partly filled with sediment before burial. Rapid covering by marine mud increased the likelihood of preservation by protecting the calcite plates from prolonged exposure, scavenging and physical breakage.
During fossilisation, the original calcite test could remain substantially intact, become mineralised or be preserved as a natural internal or external mould. Sediment may remain attached to recessed surfaces or fill openings in the test.
Surface wear and incomplete areas are common in fossil echinoids because the test was originally constructed from numerous separate plates. These natural preservation features contribute to the scientific character and individuality of each specimen.
Authentic French Fossil with Certificate
This genuine Campanian echinoid fossil is ideal for collectors of Cretaceous fossils, fossil sea urchins, French geological specimens and ancient marine life. Its prominent cidaroid morphology and Saintonge provenance make it an appealing display piece and a tangible example of France’s Upper Cretaceous marine heritage.
The specimen includes a generic Certificate of Authenticity card carrying a lifetime guarantee of authenticity. It has been individually selected for its natural appearance, geological interest and collectable character. The listing photographs show the exact specimen you will receive, and full sizing can be seen in the photographs.
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