Rare Crioceratites Heteromorph Fossil Ammonite Hauterivian Cretaceous Drome France Authentic Collectors Specimen with COA

Description

This listing is for a rare fossil ammonite of the genus Crioceratites, a distinctive heteromorph ammonite from the Hauterivian stage of the Early Cretaceous (approximately 132–129 million years ago). Collected in Drôme, France, this specimen showcases the unusual uncoiled morphology that sets heteromorph ammonites apart from their tightly coiled relatives. The fossil pictured is the exact specimen you will receive. Scale rule squares / cube = 1 cm – please see the photos for accurate sizing. Every fossil we offer is 100% genuine and comes with a Certificate of Authenticity.

Geological Context: Hauterivian, Early Cretaceous

The Hauterivian stage forms part of the Early Cretaceous and is well known for its abundant ammonite faunas, which are critical to biostratigraphy and the subdivision of Cretaceous marine rocks. During this period, much of what is now southeastern France was covered by warm shallow seas associated with the northern margin of the Tethys Ocean. These depositional environments produced marls and limestones that preserved marine life in remarkable detail.

Fossils such as Crioceratites serve as important index fossils, enabling geologists to date and correlate Hauterivian deposits across Europe and beyond. Their unusual morphology makes them particularly significant in understanding evolutionary diversification within the ammonites during the Early Cretaceous.

The Genus: Crioceratites

Crioceratites belongs to the order Ammonitida, superfamily Ancylocerataceae, and family Ancyloceratidae. Unlike the more typical planispiral ammonites, heteromorphs like Crioceratites developed uncoiled or irregularly coiled shells, often described as crioconic, where the whorls are loosely coiled without touching.

The shell of Crioceratites displays open coiling with strong ribbing, giving it a striking appearance compared to more common ammonite forms. The ribs often cross the flanks in bold, raised patterns, reinforcing the shell structure while also serving as diagnostic features for identification. This heteromorph morphology suggests adaptations for a different ecological role – possibly slower movement through the water column, drifting, or hovering rather than active swimming.

Morphological and Scientific Features

• Order: Ammonitida
• Superfamily: Ancylocerataceae
• Family: Ancyloceratidae
• Genus: Crioceratites
• Geological Stage: Hauterivian, Early Cretaceous (c. 132–129 Ma)
• Locality: Drôme, France
• Shell Traits: Heteromorph crioconic form, uncoiled whorls, strong ribbing, distinctive open structure
• Scientific Importance: Index fossil for Hauterivian biozones, key to understanding heteromorph ammonite evolution

The rare morphology of heteromorph ammonites provides valuable insight into ammonite evolution and ecology, highlighting the diversity of forms present during the Cretaceous seas.

Collector and Display Value

Heteromorph ammonites such as Crioceratites are much rarer than their planispiral relatives and are therefore especially prized by fossil collectors. Their unusual uncoiled shells make them visually striking display pieces as well as scientifically significant specimens.

This fossil originates from Drôme, France, a locality well known for its rich Hauterivian ammonite deposits. Its provenance adds further value, as French Cretaceous ammonites are highly regarded by collectors and paleontologists worldwide.

Every specimen we provide is carefully chosen for its authenticity, preservation, and scientific importance. Supplied with a Certificate of Authenticity, this rare Crioceratites heteromorph ammonite is an exceptional addition to any collection, representing both the natural beauty and evolutionary diversity of the Early Cretaceous seas.