Description
Rare Erymnoceras coronatum Ammonite Fossil from Yaxley, United Kingdom
This is an exceptional specimen of the Erymnoceras coronatum ammonite fossil, dating from the Upper Oxfordian stage of the Late Jurassic period, approximately 160–157 million years ago. Sourced from Yaxley, United Kingdom, this ammonite represents a rare and scientifically valuable species, known for its distinctive ribbed shell morphology and paleontological significance. The fossil you see in the photographs is the exact piece you will receive, pictured with a 1 cm scale cube for accurate sizing. As with all of our pieces, this fossil is a 100% genuine specimen, supplied with a Certificate of Authenticity.
Geological Context – Oxfordian Stage of the Late Jurassic
The Oxfordian stage is the earliest stage of the Upper Jurassic and is well-known for its rich fossil deposits across Europe. During this time, much of what is now the United Kingdom was covered by warm, shallow epicontinental seas that formed part of the northern margins of the ancient Tethys Ocean. These seas provided ideal conditions for the proliferation and preservation of ammonites, which flourished as both diverse and abundant faunal elements.
The fossil-bearing strata around Yaxley are characterised by calcareous marls and limestones, deposited in a marine environment that was home to a wide variety of organisms including ammonites, belemnites, bivalves, echinoids, and marine reptiles. Ammonites such as Erymnoceras serve as excellent biostratigraphic markers, helping geologists and paleontologists define precise intervals within the Oxfordian stage.
Scientific Classification
- Genus: Erymnoceras
- Species: Erymnoceras coronatum
- Family: Perisphinctidae
- Superfamily: Perisphinctoidea
- Order: Ammonitida
- Geological Stage: Upper Oxfordian, Late Jurassic (c. 160–157 million years ago)
- Locality: Yaxley, United Kingdom
Morphology and Distinctive Features
The Erymnoceras coronatum is a striking ammonite with clearly defined features that distinguish it from other Oxfordian species. Key traits include:
- Strongly ribbed ornamentation running across the whorls, providing a robust and decorative appearance.
- A generally compressed shell with involute coiling, where the outer whorls cover much of the earlier shell structure.
- Prominent tuberculation in some specimens, adding texture and character to the shell surface.
- Sutures displaying complex lobes and saddles, characteristic of its order Ammonitida.
The ribbing and sculptural details of Erymnoceras coronatum make it an attractive specimen both scientifically and aesthetically, and it is highly prized by fossil collectors for display purposes.
Paleontological Importance
Ammonites of the genus Erymnoceras are important for their role in the biostratigraphy of the Oxfordian stage. This species, E. coronatum, is associated with the Coronatum Biozone, one of the defining ammonite zones used across Europe to subdivide the Oxfordian. Such precision allows paleontologists to correlate marine strata across wide geographic regions.
The abundance and distribution of ammonites during this time also provide insight into paleoecological dynamics, as these animals were active swimmers and predators, occupying a key role in the marine food web. The study of Erymnoceras and related genera helps reconstruct evolutionary trends and faunal turnovers during the Late Jurassic.
Ancient Marine Environment
During the Oxfordian period, the region that is now Yaxley lay beneath shallow marine waters teeming with life. Ammonites such as Erymnoceras coronatum were active nektonic cephalopods, propelling themselves through the water column with jet propulsion while hunting small crustaceans, molluscs, and plankton.
These ammonites coexisted with other Jurassic marine life including belemnites, brachiopods, bivalves, crinoids, and vertebrates such as ichthyosaurs and pliosaurs. The fossil record from this period provides a vivid snapshot of a thriving and diverse ecosystem.
Collector and Display Value
This Erymnoceras coronatum ammonite fossil from Yaxley is a highly desirable collector’s item due to its rarity, preservation, and scientific importance. Its bold ribbing and natural shell features create a fossil of remarkable visual appeal, making it ideal for display in both private and educational collections.
Owning such a specimen offers not only a tangible link to the ancient seas of the Jurassic but also a piece of Earth’s deep evolutionary history, preserved for over 157 million years. Its authenticity is guaranteed, and the fossil comes complete with a Certificate of Authenticity, ensuring confidence for collectors and enthusiasts alike.
Key Details
- Fossil Type: Ammonite
- Species: Erymnoceras coronatum
- Age: Upper Oxfordian, Late Jurassic (c. 160–157 million years old)
- Locality: Yaxley, United Kingdom
- Supplied with a Certificate of Authenticity
- Exact specimen shown in photographs with 1 cm scale cube
This rare Erymnoceras coronatum ammonite fossil combines natural beauty, geological importance, and excellent provenance, making it a truly exceptional specimen for any serious fossil collection.
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