Micraster Fossil Echinoid Chalk Cretaceous Spain Authentic Collector Specimen with Certificate of Authenticity

Description

This listing features a genuine Micraster fossil echinoid from the Cretaceous Chalk deposits of Spain. Dating to approximately 90–70 million years ago, during the Upper Cretaceous, this specimen represents one of the most iconic heart urchins of the fossil record. Its preservation in chalk highlights both the geological richness of the Spanish deposits and the global distribution of these distinctive echinoids.

The fossil pictured is the actual specimen you will receive. A scale cube = 1 cm is shown in the photographs for precise sizing. As with all our specimens, this echinoid is 100% genuine and comes complete with a Certificate of Authenticity.

Geological Context: Cretaceous Chalk of Spain

During the Late Cretaceous, much of Spain was submerged beneath warm, shallow seas that formed part of the larger Tethyan Ocean system. Over millions of years, the calcareous remains of coccolithophores—microscopic plankton—accumulated on the seafloor to produce the characteristic chalk deposits in which fossils like Micraster are preserved.

The Spanish chalk successions are comparable to those of the UK and northern Europe, providing a valuable window into the paleoenvironment of the Late Cretaceous. These deposits often yield well-preserved fossils of echinoids, molluscs, ammonites, and other marine organisms, offering insight into the biodiversity and sedimentary dynamics of the time.

The Species: Micraster

Micraster is a classic genus of fossil echinoids belonging to the order Spatangoida (heart urchins), family Micrasteridae. It is among the most widely recognised and collected echinoids of the Upper Cretaceous, used extensively in biostratigraphy due to its evolutionary variation across stratigraphic levels.

Characteristic features of Micraster include:

• A distinctive heart-shaped test (shell), often slightly elongate.
• Petaloid ambulacra radiating across the surface.
• A flattened underside, adapted for shallow burrowing into soft chalky sediment.
• Tube foot pore pairs that allowed respiration and feeding.

These adaptations reveal its ecological role as an infaunal deposit feeder, living just beneath the seabed surface and processing sediment for organic matter.

Morphological and Scientific Features

• Phylum: Echinodermata
• Class: Echinoidea
• Order: Spatangoida
• Family: Micrasteridae
• Genus: Micraster
• Geological Age: Upper Cretaceous (c. 90–70 Ma)
• Locality: Spain
• Preservation: Calcareous chalk preservation, occasionally silicified
• Lifestyle: Infaunal burrower, deposit feeder
• Scientific Value: A key index fossil of the Upper Cretaceous used in biostratigraphy

Collector and Display Value

Fossils of Micraster are considered essential for any collection of Cretaceous material. Their distinctive shape, excellent preservation, and importance as stratigraphic markers make them highly valued by collectors and researchers alike.

This specimen from Spain is a fine example of the genus, offering both visual appeal and scientific interest. Supplied with a Certificate of Authenticity, it is not only a genuine fossil but also a striking natural history piece that connects you directly to the shallow seas of the Late Cretaceous.