RARE Proplanulites koenigi Fossil Ammonite | Lower Callovian Jurassic | Ashton Keynes UK | Certified Authentic Specimen

A rare and finely preserved fossil ammonite: Proplanulites koenigi, from the
Lower Callovian Stage of the Middle Jurassic, discovered at Ashton Keynes, Wiltshire, United Kingdom. This classic ammonite species represents an important part of the Callovian marine fauna and is a highly desirable addition to any fossil collection.

The specimen shown is the exact fossil you will receive, professionally photographed with a 1cm scale cube for accurate sizing. Please refer to the images for full measurements and condition.

Geological & Palaeontological Information:

• Fossil Type: Ammonite
• Species: Proplanulites koenigi
• Geological Period: Jurassic
• Stage: Lower Callovian (~165 to 163 million years ago)
• Location: Ashton Keynes, Wiltshire, England, UK
• Depositional Environment: Shallow marine, within calcareous mudstones of the Oxford Clay Formation
• Order: Ammonitida
• Superfamily: Stephanoceratoidea
• Family: Stephanoceratidae
• Biozone (Inferred): Macrocephalites macrocephalus Zone

Morphological Features:

• Moderately involute shell with broad whorls
• Faint to strong ribbing depending on growth stage
• Compressed cross-section with rounded venter
• Well-defined suture patterns

Notable Points:

• A key ammonite for Lower Callovian biostratigraphy
• Sourced from a historically significant UK locality
• Large, display-quality fossil with strong educational value

Why This Fossil is Special:

• Rare ammonite species from the Middle Jurassic
• Outstanding preservation and clarity of features
• Ethically sourced and 100% genuine
• Includes a Certificate of Authenticity