Cardioceras costicardia Fossil Ammonite Jurassic Oxfordian Dorset UK Genuine Specimen

Description

Authentic Cardioceras costicardia Fossil Ammonite from Dorset

This listing features a genuine Cardioceras costicardia fossil ammonite, carefully collected from the Oxfordian Stage of the Jurassic, Redcliff Point, Dorset, United Kingdom. This specimen is an authentic piece of natural history, representing life in the Jurassic seas around 160 million years ago. The exact fossil shown in the photographs is the one you will receive, and as with all of our pieces, it is accompanied by a Certificate of Authenticity, guaranteeing that it is 100% genuine.

Geological Age and Locality

This ammonite comes from the Oxfordian Stage of the Late Jurassic, a period spanning approximately 163 to 157 million years ago. The location of Redcliff Point, near Weymouth in Dorset, is a world-famous fossil site within the Jurassic Coast World Heritage Site. These cliffs expose Oxfordian marine deposits rich in ammonites and other marine fossils, reflecting the biodiversity of ancient shallow seas. Cardioceras costicardia is particularly well known from this site and has long been valued by collectors and geologists for its distinctive morphology and biostratigraphic importance.

Scientific Classification

• Genus: Cardioceras
• Species: Cardioceras costicardia
• Family: Cardioceratidae
• Superfamily: Stephanoceratoidea
• Order: Ammonitida
• Class: Cephalopoda
• Age: Oxfordian, Late Jurassic
• Locality: Redcliff Point, Dorset, UK

Morphological Features

Cardioceras costicardia is instantly recognisable for its strong ribbing and bold shell structure. Typical features include:

• Robust radial ribs that extend across the whorl, giving the ammonite a strikingly ribbed appearance.
• A moderately involute shell with a fairly narrow umbilicus.
• A pronounced keel running along the venter, enhancing the streamlined form.
• Ornamentation that demonstrates the evolutionary adaptations of ammonites in open marine environments.

These morphological traits make it an important fossil for palaeontological study and a visually impressive specimen for collectors.

Biostratigraphic and Scientific Importance

Cardioceras species are considered classic index fossils for the Oxfordian Stage of the Jurassic. They evolved rapidly, spread widely across Europe, and developed distinctive shell features, making them critical tools for geologists when dating and correlating Jurassic rock layers. Cardioceras costicardia is linked to the Cardioceras cordatum biozone, a key stratigraphic interval within the Oxfordian. This enhances its scientific significance as well as its value to collectors.

Depositional Environment

During the Oxfordian, the Dorset region was submerged beneath shallow epicontinental seas. These seas provided an ideal habitat for ammonites, along with other cephalopods, bivalves, and marine reptiles. The ammonites, such as Cardioceras costicardia, were agile predators, using their tentacles to catch prey such as small crustaceans and fish. When they died, their shells sank to the seabed and were gradually buried in fine marine sediments. Over millions of years, mineralisation preserved their detailed morphology, allowing us today to study and admire these ancient creatures.

Collector’s Value and Display Quality

This Cardioceras costicardia ammonite is a superb specimen for both amateur and advanced collectors. Its bold ribbing and characteristic Jurassic features make it a striking display piece. As a fossil from the internationally recognised Jurassic Coast of Dorset, it carries additional cultural and scientific value. Whether used as an educational resource, a centrepiece in a fossil collection, or simply as a natural curiosity, this ammonite connects its owner directly to the Jurassic seas of ancient Britain.

Item Details

• Fossil Type: Ammonite – Cardioceras costicardia
• Age: Oxfordian, Jurassic (approx. 163–157 million years old)
• Location: Redcliff Point, Dorset, United Kingdom
• Notable Features: Strong ribbing, ventral keel, robust shell morphology
• Scale: Rule squares/cube = 1 cm (see photos for full sizing)
• Certificate: Includes a Certificate of Authenticity
• Specimen Shown: You will receive the exact fossil pictured

A rare opportunity to own a scientifically important and visually striking Cardioceras costicardia ammonite fossil from the iconic Jurassic Coast of Dorset.