Kosmoceras jasoni Ammonite Fossil Jurassic Wiltshire UK Rare Genuine Authentic COA

Description

Authentic Jurassic Fossil from Wiltshire, UK

This fine Kosmoceras jasoni ammonite fossil is a genuine specimen from the Upper Callovian stage of the Middle Jurassic, discovered in Wiltshire, United Kingdom. A carefully selected piece, it offers not only exceptional visual appeal but also significant scientific value. The fossil comes complete with a Certificate of Authenticity, and the photographs show the actual specimen you will receive. Scale rule squares of 1 cm are included in the images to give a clear sense of size and proportion.

Geological Setting and Age

Dating to the Upper Callovian stage, approximately 164–163 million years ago, this ammonite formed when southern England was submerged beneath shallow, warm seas. Wiltshire’s Jurassic deposits, particularly within the Oxford Clay Formation and associated strata, are internationally famous for their rich fossil content. These fine-grained marine sediments created ideal conditions for the preservation of ammonites and other marine organisms, capturing details that remain visible millions of years later. The Kosmoceras genus, especially Kosmoceras jasoni, is a key component of the faunas from this stage.

Fossil Species and Classification

Kosmoceras jasoni belongs to the class Cephalopoda, order Ammonitida, and superfamily Stephanoceratoidea, within the family Kosmoceratidae. Members of this family are noted for their ornate shell structures and intricate ribbing. Kosmoceras ammonites are among the most recognisable of the Callovian, and K. jasoni in particular is often used as a biostratigraphic marker for the Jason Zone of the Upper Callovian. This makes the species not only attractive but scientifically significant, playing an important role in Jurassic stratigraphy.

Morphology and Notable Traits

This specimen displays the characteristic features of Kosmoceras jasoni, including ribbed ornamentation, tubercles (small nodules), and a compressed, planispiral whorl structure. The ribs are bold and radiate symmetrically across the flanks of the shell, with fine tubercles adding texture and visual interest. These traits made Kosmoceras highly distinctive within Jurassic ammonite faunas and continue to make them prized among fossil collectors today. Such ornamentation also provides paleontologists with insights into the evolutionary adaptations of ammonites during the Middle Jurassic seas.

Scientific and Stratigraphic Importance

As a defining species of the Jason Zone in the Upper Callovian, Kosmoceras jasoni is a critical index fossil. Its presence in geological layers allows researchers to precisely identify and correlate rock strata across Europe. Fossils of this species are integral to the study of Jurassic marine biostratigraphy and paleoecology. For collectors, owning a specimen of K. jasoni is to possess not just a striking fossil but a key piece of Earth’s geological record.

Condition and Presentation

The fossil has been carefully prepared to preserve its natural form and enhance the visibility of its defining features. Ribbing and tubercle details are clearly visible, along with the elegant spiral curvature of the whorl. This is a genuine, one-of-a-kind fossil, not a cast or reproduction. The images provided are of the exact specimen you will receive, giving you complete confidence in your purchase.

Guarantee of Authenticity

All of our fossils are 100% genuine specimens, responsibly sourced and scientifically identified. Every purchase includes a Certificate of Authenticity to verify provenance. This Kosmoceras jasoni ammonite fossil from Wiltshire is a rare and scientifically important specimen, making it a highly desirable addition for fossil collectors, natural history enthusiasts, and educational collections alike.