Description
Rare Kosmoceras proniae Iridescent Fossil Ammonite from Russia
This listing features a rare Kosmoceras (Lobokosmoceras) proniae ammonite fossil, an outstanding specimen from the Callovian stage of the Middle Jurassic period, dating back approximately 165 – 161 million years. Sourced from the fossil-rich deposits of Ryazan, Russia, this ammonite is a striking piece that combines superb preservation with natural iridescence, giving its shell a shimmering rainbow-like play of colours that makes it highly desirable for collectors.
The photos show the exact specimen you will receive, with a 1 cm scale cube included for accurate size reference. Every fossil in our collection is carefully selected, genuine, and supplied with a Certificate of Authenticity, ensuring both its provenance and its scientific integrity.
Geological Setting
The fossil originates from the Callovian stage of the Middle Jurassic epoch, a period characterised by widespread shallow seas that covered much of Europe and Russia. The Ryazan region is world-famous for its fossil-bearing clay and marl deposits, which provided perfect conditions for the preservation of ammonites. These marine sediments, rich in carbonate, created a low-oxygen seabed environment that prevented decay and allowed fine shell details to fossilise, including the rare preservation of iridescent nacre.
Ammonites like Kosmoceras proniae are not only prized for their beauty but also serve as important index fossils, used in stratigraphy to identify and correlate Jurassic sedimentary layers across Europe and Asia.
Scientific Classification
- Genus: Kosmoceras
- Subgenus: Lobokosmoceras
- Species: Kosmoceras proniae
- Order: Ammonitida
- Superfamily: Stephanoceratoidea
- Family: Kosmoceratidae
The Kosmoceratidae family is well known for its complexly ornamented shells, often with ribbing, nodes, and intricate suture lines. The subgenus Lobokosmoceras is particularly recognised for its lobate, ribbed morphology and distinctive shell architecture, marking it out as a fascinating evolutionary branch of the genus.
Morphological Features
This Kosmoceras (Lobokosmoceras) proniae fossil displays a combination of unique structural traits and natural beauty:
- Strong ribbed ornamentation with pronounced costae running across the whorls.
- A lobed shell profile, characteristic of Lobokosmoceras.
- Evidence of tubercles and subtle nodes, typical of the genus.
- Well-preserved suture patterns, showing the intricate complexity of ammonite septal divisions.
- Stunning natural iridescence, producing shimmering reflections of green, gold, and violet under light.
These features make this species not only an essential specimen for scientific study but also a visually captivating piece of natural art.
Paleoecology and Life History
Ammonites such as Kosmoceras proniae were nektonic marine predators, living actively in the water column. Their diet would have included small crustaceans, molluscs, and plankton. The ribbing and ornamentation of their shells may have served both hydrodynamic functions and as protection from predators, which included marine reptiles like ichthyosaurs and pliosaurs.
The shallow epicontinental seas of the Middle Jurassic created rich marine ecosystems, and the fossiliferous beds of Ryazan record a thriving community of ammonites, belemnites, brachiopods, and marine reptiles. Fossils from this region are celebrated worldwide for their exceptional preservation.
Collector Value and Display
This specimen is a highly desirable collector’s piece, combining scientific importance with striking aesthetic qualities. The natural iridescence of the shell makes it a visually stunning fossil, perfect for display in a cabinet of curiosities, as part of a natural history collection, or as a unique decorative specimen.
Ammonites from the Ryazan deposits are internationally renowned for their quality, and this Kosmoceras proniae offers an excellent opportunity to own a piece of genuine Jurassic history. Its well-preserved morphology and rare iridescent nacre highlight its uniqueness, making it a specimen that stands out among ammonite fossils.
Key Features
- Species: Kosmoceras (Lobokosmoceras) proniae
- Age: Middle Jurassic, Callovian stage (approx. 165 – 161 million years old)
- Origin: Ryazan, Russia
- Family: Kosmoceratidae, Superfamily Stephanoceratoidea
- Features: Ribbed ornamentation, lobate shell profile, iridescent nacre
- Supplied with a Certificate of Authenticity
- Exact specimen shown in photos with 1 cm scale cube
This rare Kosmoceras proniae ammonite is both a scientifically significant fossil and a natural treasure. It represents the rich marine life of the Jurassic seas and offers collectors an irreplaceable glimpse into ancient Earth history.
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