Rare Acompsoceras renevieri Fossil Ammonite Middle Cenomanian Cretaceous Sussex UK 7 Inch Genuine Certified Collector Specimen

Description

Rare Acompsoceras renevieri Fossil Ammonite from Sussex, United Kingdom

This superb Acompsoceras renevieri fossil ammonite is a rare and scientifically significant specimen from the Middle Cenomanian stage of the Late Cretaceous, discovered in the fossil-rich chalk deposits of Sussex, UK. Measuring approximately 7 inches in diameter, it displays exceptional preservation, making it an ideal addition for both collectors and educational purposes. The specimen shown in the photographs is the exact fossil you will receive, ensuring complete authenticity.

Geological Age and Origin

The Middle Cenomanian stage, dating to around 100.5–93.9 million years ago, marks the earliest part of the Late Cretaceous. During this period, much of what is now southern England was covered by warm, shallow seas. In Sussex, these seas deposited thick layers of chalk and marl, creating perfect conditions for the fossilisation of marine organisms such as ammonites. The calm, open-marine environment preserved the intricate details of shells, allowing today’s collectors to admire the structure and beauty of these ancient cephalopods.

Scientific Classification

• Species: Acompsoceras renevieri
• Family: Acanthoceratidae
• Superfamily: Acanthoceratoidea
• Order: Ammonitida
• Geological Stage: Middle Cenomanian, Late Cretaceous

Acompsoceras renevieri is recognised as an important biostratigraphic indicator within Cenomanian chalk sequences, helping paleontologists correlate rock layers and refine the geological timescale.

Morphological Features

This specimen of Acompsoceras renevieri exhibits all the defining features of the species:

• Strongly ribbed whorls with well-defined, radiating costae that extend from the umbilicus to the venter.
• Rounded ventral area with slightly projecting ribs, giving a robust and balanced appearance.
• Moderately involute coiling, leaving a distinct and open umbilicus that adds visual interest.
• Clear suture patterns, showing the complex internal septa that divided the ammonite’s buoyancy chambers.

These features are not only aesthetically striking but also essential for accurate species identification.

Paleoecology and Life Habits

As an active, free-swimming predator, Acompsoceras renevieri would have occupied mid-water zones in the warm Cretaceous seas, hunting small fish, crustaceans, and plankton. Like modern cephalopods, it used jet propulsion for movement and had well-developed eyes for detecting prey. Its shell’s chambered structure allowed precise buoyancy control, enabling it to navigate efficiently through the marine environment.

When the animal died, its shell sank to the seabed, becoming buried in fine carbonate sediments. Over millions of years, these sediments compacted and lithified into chalk, while the ammonite shell was mineralised, preserving its shape and detail for future discovery.

Collector Significance and Authenticity

A specimen of this size, quality, and rarity from Sussex is highly sought after. Its combination of scientific relevance, aesthetic appeal, and excellent preservation makes it a standout piece for collectors, museums, or educational displays.

All of our fossils are 100% genuine specimens and are supplied with a Certificate of Authenticity for complete peace of mind. This ensures both the accuracy of the fossil’s identification and the integrity of its provenance. This Acompsoceras renevieri ammonite offers a tangible connection to the ancient seas of the Cretaceous period, bringing a piece of Earth’s history into your collection.