Description
Authentic Kosmoceras duncani Ammonite Fossil from La Rioja, Spain
This exceptional specimen is a genuine Kosmoceras duncani ammonite fossil collected from the Callovian Stage of the Middle Jurassic, discovered in the region of La Rioja, Spain. Dating back around 166 to 163 million years, this ammonite is an outstanding representation of one of the most iconic cephalopods of the Jurassic seas. Unlike modern squid and octopus, ammonites built coiled, chambered shells that provide us with an incredible fossil record today. Each fossil is a unique and irreplaceable piece of natural history, and this specimen is the exact one shown in the photographs, measured against a 1 cm scale cube for reference.
Every fossil we offer is 100% genuine, carefully selected for quality and authenticity, and comes with a Certificate of Authenticity for your peace of mind.
Geological Context – The Jurassic Seas of Spain
The fossil originates from the Callovian Stage, an important subdivision of the Middle Jurassic. This was a time when much of Europe was covered by warm epicontinental seas, providing ideal conditions for the flourishing of ammonites. The marine environments of La Rioja were dominated by sedimentation that preserved marine fauna in remarkable detail, resulting in the fine fossil record for which the region is known today.
The Kosmoceratidae family is particularly significant for paleontologists as many of its members are used as biostratigraphic markers, helping to date and correlate rock layers across Europe. The presence of Kosmoceras duncani in the Callovian deposits provides key evidence for reconstructing Jurassic marine ecosystems and evolutionary history.
Scientific Classification
- Type: Ammonite Fossil
- Genus: Kosmoceras
- Species: duncani
- Order: Ammonitida
- Superfamily: Stephanoceratoidea
- Family: Kosmoceratidae
- Age: Callovian, Middle Jurassic (~166–163 million years ago)
- Locality: La Rioja, Spain
Morphological Features
The genus Kosmoceras is renowned for its ornamented shell structure. This specimen of Kosmoceras duncani displays key morphological features:
- A moderately involute, tightly coiled shell with clearly defined ribbing.
- Strongly ribbed whorls, with ribs crossing the flanks and often branching.
- Characteristic tubercles or nodules along the ribs, adding to its striking appearance.
- The complex suture lines typical of Kosmoceras, though partially obscured in fossil preservation.
These features not only add visual appeal but also provide crucial insights into the ammonite’s buoyancy and lifestyle within the Jurassic marine environment.
Paleoecological Importance
As active marine predators, ammonites such as Kosmoceras duncani would have been an integral part of the food chain, feeding on smaller invertebrates and possibly plankton. Their shells, when fossilised, provide a detailed record of evolutionary adaptations, including shell shape, ornamentation, and size variation. The distinctive ribbing and tuberculation suggest adaptations for both shell strength and hydrodynamic efficiency.
Ammonites also served as prey for larger marine reptiles such as plesiosaurs and pliosaurs, making them a crucial link in the Jurassic marine ecosystem. The abundance of Kosmoceras in the Callovian further underscores the diversity and productivity of the seas in this region during the Middle Jurassic.
Collector and Display Value
A Kosmoceras duncani ammonite fossil from La Rioja is not only a scientifically important specimen but also a highly attractive piece for display. Its ribbed and ornamented shell structure makes it visually striking, while its provenance from one of Europe’s most famous Jurassic fossil localities adds to its significance.
Collectors of ammonites, students of paleontology, or those with an appreciation for natural history will find this specimen particularly appealing. Its authenticity is fully guaranteed, and it represents a genuine link to the Jurassic seas that once covered Spain.
Key Features
- Species: Kosmoceras duncani
- Age: Callovian, Middle Jurassic (~166–163 million years ago)
- Origin: La Rioja, Spain
- Notable Traits: Ribbed and tuberculate shell, characteristic Kosmoceras morphology
- Authenticity: 100% genuine fossil with Certificate of Authenticity
- Display: Exact specimen shown with 1 cm scale cube for sizing reference
This rare Kosmoceras duncani ammonite is both a scientifically significant fossil and a beautiful addition to any collection, embodying the evolutionary story of the Jurassic seas.
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