RARE Arisphinctes helenaes Fossil Ammonite – Middle Oxfordian – Jurassic – LE VANNEAU, Deux-Sèvres, France – Genuine Specimen with COA

Description Presenting a RARE and genuine fossil ammonite of the species Arisphinctes helenaes from the Middle Oxfordian stage of the Jurassic Period, unearthed in Le Vanneau, Deux-Sèvres, France. This beautifully preserved fossil is a superb example of Middle Jurassic ammonite diversity, showcasing the intricate shell features characteristic of the Arisphinctes genus. Fossil Type: Ammonite (extinct marine cephalopod) Species: Arisphinctes helenaes Geological Period: Jurassic Geological Stage: Middle Oxfordian (~160 million years ago) Locality: Le Vanneau, Deux-Sèvres, France Formation: Oxfordian marine limestone and marl strata, typical of the region Scientific and Geological Details: Order: Ammonitida Superfamily: Perisphinctoidea Family: Perisphinctidae Morphology Features: Moderately involute shell with fine, bifurcating ribbing Whorls are compressed, showing typical evolute form Suture lines moderately complex, in line with Oxfordian ammonites Depositional Environment: Shallow epicontinental seas of the Tethys margin Fossil preserved in calcareous marine sediment, indicating a relatively low-energy depositional setting Biozone: Likely within the Arisphinctes biozone of the Oxfordian ammonite zonation Notable: Arisphinctes helenaes is a significant zonal index fossil for the Middle Oxfordian in Western Europe Species described as part of regional ammonite faunas used in refining Jurassic chronostratigraphy Formally Described By: Specific taxonomic authority not conclusively recorded for this locality; often included in classic Oxfordian ammonite catalogues such as those by W. J. Arkell Why This Fossil Is a Standout Specimen: A rare and highly collectible ammonite species Authentic fossil with distinct ornamentation Offers excellent insight into mid-Oxfordian marine life Ideal for collectors, display, teaching or paleontology reference Sourced from a scientifically important Jurassic site in western France Additional Information: All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity Scale Rule Squares / Cube = 1cm: Full sizing please see photo This listing includes the exact specimen shown – no stock images used. Your piece has been hand-selected for its quality and clarity