RARE 4.5″ Calycoceras madagascarense Fossil Ammonite Cenomanian Cretaceous Madagascar – Genuine Authentic Specimen with COA

Description

This listing features a rare 4.5-inch Calycoceras madagascarense fossil ammonite from the Cenomanian stage of the Late Cretaceous period, sourced from the fossil-rich deposits of Madagascar. This remarkable specimen has been hand-selected for its exceptional preservation, striking detail, and natural beauty, making it a prized acquisition for fossil enthusiasts, collectors, and educational displays alike. The photographs provided show the actual fossil you will receive, ensuring complete transparency and confidence in your purchase.

Geological Age & Formation

Calycoceras madagascarense thrived during the Cenomanian stage, approximately 100.5 to 93.9 million years ago, a time when vast areas of present-day Madagascar were submerged beneath warm, shallow seas. The region’s marine sediments created ideal conditions for the preservation of ammonites, entombing them in fine-grained material that allowed their intricate shell morphology to be fossilised in extraordinary detail. The deposits in which this specimen was found are part of Madagascar’s renowned Cretaceous marine strata, celebrated for producing beautifully preserved ammonites with well-defined sutures and shell ornamentation.

Species Identification & Morphology

Belonging to the family Acanthoceratidae within the superfamily Acanthoceratoidea and order Ammonitida, Calycoceras madagascarense is distinguished by its moderately involute, strongly ribbed shell with prominent tubercles on the flanks. These features are not merely decorative—they reflect evolutionary adaptations to its marine environment. The ribs and tubercles likely provided hydrodynamic benefits and structural strength, while the planispiral coiling offered streamlined movement through the ancient Cretaceous seas. This specimen displays these diagnostic traits clearly, offering a fascinating glimpse into the morphology of a species that swam in oceans alongside marine reptiles, large predatory fish, and other cephalopods.

Notable Collector Qualities

• Size: Approximately 4.5 inches across (scale rule cube in photographs = 1 cm squares for accurate sizing).
• Preservation: Excellent detail with clear ribbing and ornamentation.
• Authenticity: Guaranteed 100% genuine fossil, supplied with a Certificate of Authenticity.
• Display-Ready: The natural beauty of the specimen makes it ideal for display in a cabinet, office, study, or educational setting.
• Rarity: Calycoceras madagascarense is a sought-after species for both its scientific importance and aesthetic appeal.

Paleoenvironment & Scientific Importance

During the Cenomanian, Madagascar’s marine environments were teeming with life. This ammonite lived in warm, nutrient-rich seas, likely occupying a predatory or scavenging role within the mid-water column. Its shell’s buoyancy control chamber system (phragmocone) allowed it to navigate through varying depths, hunting small crustaceans, mollusks, and other prey. Fossils such as this are invaluable for paleontologists, providing insight into evolutionary patterns, paleobiogeography, and the biodiversity of Late Cretaceous marine ecosystems.

Perfect for Collectors, Educators & Enthusiasts

Whether you are an experienced fossil collector, a geology enthusiast, or looking for a truly unique natural history gift, this Calycoceras madagascarense ammonite will be a highlight of any collection. Its combination of rarity, scientific significance, and natural beauty ensures it will be appreciated for generations to come.

All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. The fossil pictured is the exact specimen you will receive.