Description
Genuine Osperlioceras beauliziense Ammonite Fossil
This genuine ammonite fossil is identified as Osperlioceras beauliziense and originates from Aveyron in the Occitanie region of southern France. It dates from the Upper Toarcian of the Lower Jurassic and is recorded from the Insigne Zone, providing valuable geological and biostratigraphic context.
This ammonite inhabited a warm marine environment approximately 175 million years ago, during the closing part of the Early Jurassic. Its chambered shell represents an extinct cephalopod that lived within the water column above a seabed populated by diverse marine organisms.
The fossil has been carefully chosen for its identifiable ammonite form, geological interest and documented French provenance. The listing photographs show the exact specimen you will receive, allowing its natural shell profile, ornamentation, colour, matrix and individual state of preservation to be examined before purchase. Full sizing and scale information are shown in the photographs.
Species Identification and Classification
Osperlioceras beauliziense belongs to the ammonites, an extinct and highly diverse group of marine molluscs that flourished throughout much of the Mesozoic Era. Ammonites were members of the class Cephalopoda and were related to living squid, cuttlefish, octopuses and nautiluses.
Broad scientific classification includes:
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Superfamily: Hildoceratoidea
Family: Hildoceratidae
Genus: Osperlioceras
Species: Osperlioceras beauliziense
Members of the Hildoceratidae are especially important in Lower Jurassic palaeontology. Their changing shell forms, ornamentation and ventral structures help geologists distinguish successive intervals within the Toarcian marine succession.
Ammonite identification is based on a combination of characteristics, including shell coiling, whorl proportions, umbilical width, flank ornamentation, ventral shape and suture pattern. These features can vary as the animal grows, and the amount of visible detail also depends upon the specimen’s natural preservation.
Osperlioceras Shell Morphology
The shell of Osperlioceras beauliziense developed as a planispiral coil, meaning that successive whorls grew around one another within approximately the same plane. The degree to which later whorls overlap the earlier growth stages determines the width of the central opening, known as the umbilicus.
Osperlioceras ammonites are generally associated with compressed and relatively streamlined shell forms. Their whorls may appear narrow when viewed from the front, with flattened or gently convex flanks converging towards the outer edge.
The shell surface may display fine ribs, folds or growth lines following a curved or gently sickle-shaped course across the flanks. These markings can sweep forwards towards the venter and may vary in strength and spacing during growth.
The venter is the outermost edge of the coiled shell. In many hildoceratid ammonites, this region carries a longitudinal keel that forms a raised ridge around the shell. The combination of compressed whorls, curved ornamentation and a defined ventral area gives these ammonites their characteristic appearance.
Depending upon preservation, this fossil may retain mineral-replaced shell material, an internal sedimentary mould or a combination of both. Fine surface details may be sharper where the shell exterior survives and more subdued where the internal mould is exposed.
Chambered Shell and Ammonite Growth
Internally, the ammonite shell was divided by curved partitions called septa. These created a sequence of chambers connected by a narrow tube known as the siphuncle.
The living animal occupied only the final and largest body chamber. As it grew, it added new material around the shell aperture, moved forwards and sealed the older portion behind itself with another septum. This continuous process produced the chambered spiral preserved in the fossil record.
The abandoned chambers contributed to buoyancy regulation. By controlling the balance of fluid and gas within them, the ammonite could maintain or alter its position within the marine water column.
Where the septa joined the inner surface of the shell wall, they formed intricate patterns known as suture lines. These structures are important in ammonite classification and provide evidence of relationships between different families, genera and evolutionary lineages.
The living animal would have extended its head, eyes and muscular arms from the shell opening. It probably fed upon small marine organisms and organic material present within the surrounding Jurassic sea.
Upper Toarcian Insigne Zone
This fossil is recorded from the Insigne Zone of the Upper Toarcian. The Toarcian was the final stage of the Lower Jurassic, following the Pliensbachian and preceding the Aalenian, which marks the beginning of the Middle Jurassic.
The Insigne Zone represents a defined interval within the later Toarcian succession. Ammonite biozones are recognised through characteristic fossil assemblages and allow sedimentary rocks to be arranged into a much more detailed chronological sequence than a broad Jurassic age alone would provide.
Ammonites are especially valuable index fossils because their shell forms evolved relatively rapidly, many species existed for restricted spans of time and populations could become distributed across extensive connected seas. Their fossils therefore allow geologists to correlate marine strata between different localities.
The recorded Insigne Zone provenance places this specimen within a specific episode of Early Jurassic marine history. This level of information is particularly desirable for collectors interested in scientifically documented ammonites, stratigraphy and European Jurassic geology.
Early Jurassic Marine Environment
During the Upper Toarcian, the region now forming Aveyron was covered by a warm sea linked to the western margins of the ancient Tethys Ocean. Marine basins and submerged platforms extended across large parts of southern and western Europe.
These waters supported ammonites, belemnites, nautiloids, bivalves, gastropods, brachiopods, crustaceans, fish and marine reptiles. Microscopic plankton formed an essential part of the food web and contributed organic and calcareous material to the sediment accumulating below.
Fine mud, clay and carbonate particles settled on the seabed. Changes in sea level, water circulation, oxygen availability, biological productivity and sediment supply produced alternating layers of limestone and marl.
Osperlioceras beauliziense lived within the water column above this seabed. Its compressed chambered shell provided buoyancy and a streamlined profile within an environment shared with numerous other cephalopods and marine invertebrates.
Aveyron, Occitanie Fossil Provenance
Aveyron is internationally recognised for its fossil-rich Lower Jurassic rocks and diverse Toarcian ammonite faunas. The region contains extensive exposures of marine limestone and marl deposited within ancient sedimentary basins.
These rock successions have yielded many ammonite genera and species representing successive intervals of Toarcian time. Their study has contributed to understanding ammonite evolution, Early Jurassic marine environments and the correlation of fossil-bearing strata across Europe.
A specimen retaining its species identification, Insigne Zone attribution and Aveyron provenance has considerably greater scientific and educational context than an ammonite offered without locality or stratigraphic information.
The documented origin connects this fossil directly with one of France’s classic Lower Jurassic collecting regions and makes it especially appealing for collections focused on Toarcian ammonites or European palaeontology.
Natural Fossilisation and Preservation
After the ammonite died, its shell descended to the seabed. Currents, scavenging organisms and sediment movement may have affected it before final burial.
Fine marine sediment entered the empty shell chambers and accumulated around the exterior. As further layers were deposited, pressure compacted the sediment and gradually transformed it into sedimentary rock.
The original shell consisted mainly of aragonite, a form of calcium carbonate that may dissolve, recrystallise or be replaced by other minerals during fossilisation. Sediment filling the chambers could harden into an internal mould that retained the ammonite’s coiling, whorl profile and surface ornamentation.
Natural fractures, incomplete edges, worn ribs, matrix deposits, mineral markings and colour variations are authentic products of burial and geological alteration. These characteristics form part of the specimen’s individual history and ensure that every genuine fossil is unique.
Actual Specimen and Certificate of Authenticity
This is a genuine fossil specimen and not a cast, replica or artificial reproduction. The listing photographs show the exact Osperlioceras beauliziense ammonite that will be supplied, allowing its natural shell form, ornamentation, matrix, mineral colouring and individual preservation to be viewed before purchase.
Full sizing is provided in the listing photographs.
The fossil includes a generic Certificate of Authenticity card carrying a lifetime guarantee. Its identifiable hildoceratid morphology, Upper Toarcian age, Insigne Zone attribution and documented Aveyron provenance make it an excellent addition to a Jurassic ammonite collection, French fossil display, natural-history cabinet or educational geological collection.
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