Description This listing is for a rare and striking 3.5″ Fossil Ammonite specimen of Sigaloceras calloviense from the Lower Callovian Stage of the Jurassic Period, expertly preserved and sourced from Waterpark, Ashton Keynes, United Kingdom. The fossil shown in the photograph is the exact specimen you will receive, ensuring transparency and trust. Scale rule and cube are provided in the images for accurate measurement — each square/cube = 1cm. Full sizing and views of the fossil are shown in the photos. Key Geological and Scientific Information: Species: Sigaloceras calloviense Fossil Type: Ammonite (extinct marine cephalopod) Geological Period: Jurassic Geological Stage: Lower Callovian (Middle Jurassic) Location: Waterpark, Ashton Keynes, Wiltshire, England, UK Approximate Age: ~164 million years ago Order: Ammonitida Superfamily: Stephanoceratoidea Family: Sigaloceratidae Morphology Features: This specimen of Sigaloceras calloviense exhibits the classic involute coiling typical of the genus, with fine ribbing and a moderately compressed shell profile. These features are characteristic of ammonites adapted to open marine conditions, and the detail is exceptionally well-preserved in this piece. Depositional Environment: This ammonite comes from marine clay and limestone deposits associated with the Oxford Clay Formation, which represents a low-energy, offshore marine environment. These conditions allowed for exceptional preservation of marine fauna, including a diverse assemblage of ammonites. Biozone & Zone Information: The Sigaloceras calloviense species defines the Calloviense Subzone of the Calloviense Zone, a key biozone used in the biostratigraphy of the Middle Jurassic in Europe. Scientific Significance: Sigaloceras is an important index fossil for the Callovian Stage, used in correlation of Jurassic marine sediments across Europe. This genus is part of the evolutionary lineage that gives valuable insight into paleoenvironments and cephalopod development during the Jurassic. Authenticity Guarantee: All of our fossils are 100% genuine specimens and are carefully selected for their scientific and aesthetic value. Each specimen comes with a Certificate of Authenticity. Add this scientifically important and visually stunning ammonite to your collection today!
