Description
Available here is a Rare 4.25″ Fossil Ammonite of Catasigaloceras planicerclus from the Lower Callovian Stage of the Jurassic Period, found at Waterpark, Ashton Keynes, United Kingdom — a site renowned for its rich and scientifically important marine fossils.
The photographs show the exact specimen you will receive, carefully selected for its preservation, size, and scientific integrity.
Scale Rule Squares / Cube = 1cm — please refer to the photo for precise sizing.
Key Geological and Scientific Information:
- Species: Catasigaloceras planicerclus
- Fossil Type: Ammonite (extinct marine cephalopod)
- Geological Period: Jurassic
- Geological Stage: Lower Callovian (Middle Jurassic)
- Location: Waterpark, Ashton Keynes, Wiltshire, England, UK
- Formation: Likely Kellaways Beds (Callovian marine clay and silt)
- Approximate Age: ~164 million years ago
- Order: Ammonitida
- Superfamily: Stephanoceratoidea
- Family: Sigaloceratidae
- Formally Described By: S.S. Buckman, early 20th century
Morphology Features: Catasigaloceras planicerclus is a distinctive ammonite known for its flattened, smooth-sided whorls with a relatively broad and planulate shell. The venter (outer edge) is typically narrow and may be subtly keeled or rounded depending on growth stage and preservation. This species generally exhibits fine ribbing or near-smooth ornamentation, contributing to its clean and elegant appearance. This specimen beautifully illustrates these features, making it an excellent representative of the genus.
Depositional Environment: The ammonite was preserved in offshore marine deposits, most likely from the Kellaways Beds, a layer of fine-grained clay and siltstones formed in a low-energy, shelf environment. These marine sediments were ideal for fossil preservation, especially for cephalopods.
Biozone & Stratigraphy: While not a zone-defining species itself, Catasigaloceras planicerclus is generally associated with the Calloviense Zone of the Lower Callovian, contributing to stratigraphic resolution and fossil correlation in southern England and adjacent European basins.
Scientific Importance: This species represents a refined evolutionary stage within the Sigaloceratidae family. It offers insight into the subtle morphological shifts in ammonite evolution during the Middle Jurassic and is valued both as a collector’s specimen and a reference fossil for biostratigraphic work.
Authenticity Guarantee: All of our fossils are 100% genuine specimens, carefully sourced and professionally handled. A Certificate of Authenticity is included with every fossil we sell, offering peace of mind and provenance.
This Catasigaloceras planicerclus ammonite is a beautiful and scientifically meaningful specimen — a rare and valuable addition to any fossil collection or Jurassic display.
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