Description
Genuine Prorasenia paralelepida Ammonite Fossil
This carefully chosen specimen is a genuine Prorasenia paralelepida ammonite fossil from the Kimmeridge Limestone at Böttingen, Baden-Württemberg, Germany. It dates to the Kimmeridgian Stage of the Upper Jurassic and represents an extinct marine cephalopod that lived in the ancient seas covering southern Germany approximately 152 to 157 million years ago.
Prorasenia paralelepida belongs to the ammonites, an exceptionally successful group of prehistoric molluscs related to modern squid, cuttlefish, octopuses and nautiluses. Ammonites inhabited the world’s oceans for hundreds of millions of years before disappearing during the mass extinction at the end of the Cretaceous Period.
The combination of a species-level identification, Upper Jurassic age and precise German provenance gives this specimen excellent geological, educational and collection interest. It is particularly suitable for collectors of European ammonites, German fossils, Kimmeridgian marine life and genuine natural-history specimens.
Prorasenia Ammonite Morphology
The shell of Prorasenia paralelepida was planispirally coiled, meaning that its successive whorls developed within a single plane around a central umbilicus. As the animal grew, new shell material was added continuously at the aperture, causing each later whorl to expand around the earlier growth stages.
Members of Prorasenia generally possess an evolute to moderately involute shell form, with part of the inner whorls remaining visible within the umbilical region. The shell surface may display strong radial ribbing that changes in spacing, prominence or direction as it crosses the flanks towards the outer margin.
Depending on the specimen’s growth stage and preservation, visible features may include the central umbilicus, overlapping whorls, primary and secondary ribs, the ventral region, growth markings and sections of the body chamber or chambered phragmocone. The robust ornament would have strengthened the shell while also contributing to the distinctive appearance used in ammonite classification.
Natural fractures, worn ribs, incomplete margins, mineral-filled cracks and attached limestone matrix are normal characteristics of an authentic Jurassic ammonite. These features reflect the shell’s life, burial, fossilisation and subsequent exposure from the surrounding rock.
Chambered Shell and Buoyancy Control
The ammonite shell was divided internally by curved mineralised walls called septa. These created a succession of chambers collectively known as the phragmocone. The living animal occupied only the final and largest portion of the shell, known as the body chamber.
A narrow tube called the siphuncle passed through the internal chambers. By regulating the balance of liquid and gas within these spaces, the ammonite could control its buoyancy and maintain a suitable position within the water column.
Where the septa joined the outer shell, they produced intricate lines known as sutures. These folded patterns strengthened the shell and provide important anatomical features for distinguishing major ammonite groups. Sutures may become visible where the outer shell has naturally weathered away or has been carefully prepared.
The soft-bodied animal projected from the shell aperture and probably possessed arms positioned around a hard, beak-like mouth. Movement was achieved through jet propulsion, while the chambered shell acted as a buoyancy apparatus and protective structure.
Life in the Kimmeridgian Sea
During the Kimmeridgian Stage, southern Germany was covered by a warm marine environment connected to the extensive seas of Late Jurassic Europe. The modern hills and valleys of Baden-Württemberg did not yet exist, and carbonate-rich sediment accumulated across the submerged region.
Prorasenia paralelepida shared these waters with other ammonites, belemnites, bivalves, gastropods, brachiopods, crinoids, echinoids, crustaceans, fish and marine reptiles. These animals occupied habitats ranging from the carbonate seabed to the open water above it.
The ammonite was probably a mobile predator or opportunistic feeder. It may have consumed small crustaceans, planktonic animals, juvenile molluscs and other suitably sized prey. Its arms and beak-like mouth would have allowed it to capture and process food, while buoyancy control helped it move through different levels of the water column.
After death, the soft tissues decayed and the shell descended to the seabed. Sediment entered the body chamber and any damaged internal chambers before the remains were gradually buried. Burial protected the shell from complete destruction and began the long process through which it became fossilised.
Kimmeridge Limestone Geology
The Kimmeridge Limestone associated with this specimen records marine carbonate deposition during the Upper Jurassic. Limestone developed from carbonate mud, microscopic particles and the broken skeletal material of organisms living within the Jurassic sea.
Changes in water depth, current strength, oxygenation and biological productivity influenced the character of individual beds. Some layers formed under relatively quiet offshore conditions, while others contain concentrated shells and fragments produced by stronger currents, storms or reduced rates of sediment accumulation.
Over time, the accumulating sediment compressed under the weight of younger deposits. Mineral-rich water circulated through pores and cavities, cementing the carbonate grains and transforming the original seabed sediment into solid limestone.
The ammonite’s original aragonitic shell may have been altered, dissolved or replaced during fossilisation. Sediment filling the shell could harden into a natural internal mould, preserving its coiled form, ribs and other external or internal details even where the original shell material was no longer present.
Böttingen, Baden-Württemberg Provenance
Böttingen lies within Baden-Württemberg in south-western Germany, a region renowned for its extensive Upper Jurassic sedimentary rocks and scientifically important ammonite faunas. Fossils from this area preserve a detailed record of the marine environments that occupied the region before later uplift and erosion created the modern landscape.
The locality is associated with fossil-bearing Kimmeridgian strata containing diverse ammonite assemblages. These ammonites are valuable for comparing individual beds and reconstructing the sequence of environmental and biological changes occurring within the Late Jurassic sea.
A precise locality adds considerable collection value because it connects the fossil to a recognised geological setting rather than identifying it only as a general German ammonite. This specimen’s recorded association with Böttingen, Baden-Württemberg, provides important geographical and stratigraphical context.
It is especially suitable for collections focused on ammonites, Upper Jurassic fossils, German palaeontology, European marine deposits, extinct cephalopods or specimens from classic fossil localities.
Authentic Fossil with Certificate of Authenticity
This is a genuine natural fossil and not a replica, cast or manufactured reproduction. Its coiled shape, ribbing, colour, texture and state of preservation result from the original Prorasenia paralelepida shell and the geological processes it experienced over millions of years.
The photograph shows the actual carefully chosen specimen you will receive. Please examine the supplied images closely, as they provide the best record of its exact condition, preserved ornament, attached matrix and individual appearance.
Full sizing please see photo.
The fossil includes a generic Certificate of Authenticity card supported by our lifetime guarantee of authenticity.
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