Description
Rare Laevaptychus latus Aptychus Fossil – Genuine Upper Jurassic Ammonite Operculum
This is a rare and genuine Laevaptychus latus aptychus fossil, representing an ammonite operculum or mouth part from the Kimmeridge Clay Formation of Westbury, Wiltshire, UK. Dating to the Upper Jurassic, Kimmeridgian stage, this specimen is an unusual and highly collectable fossil connected to ammonites, the famous extinct marine cephalopods that dominated many Jurassic seas. Unlike a typical coiled ammonite shell, an aptychus represents part of the animal’s body apparatus, making it a fascinating fossil for collectors interested in ammonite anatomy, rare Jurassic material, and British palaeontology.
This fossil is a carefully chosen piece, with the photograph showing the actual specimen you will receive. It also includes a Certificate of Authenticity lifetime guarantee generic card, making it an excellent choice for fossil collectors, natural history displays, geology students, educational collections, and anyone interested in genuine British Jurassic fossils.
Geology, Age and Location
This fossil comes from the Kimmeridge Clay Formation at Westbury, Wiltshire, a classic Upper Jurassic marine deposit in the UK. The specimen is Kimmeridgian in age, dating to approximately 157 to 152 million years ago. During this time, southern Britain was covered by a warm to temperate marine sea, where fine muds, organic-rich sediments, and marine remains accumulated on the seabed.
The Kimmeridge Clay Formation is one of Britain’s most famous Jurassic fossil-bearing units. It is known for preserving ammonites, belemnites, bivalves, marine reptiles, fish, crustaceans, and other marine life. Its dark clay and shale layers were deposited in relatively quiet marine conditions, often with low oxygen levels on or near the seabed. These conditions helped preserve delicate or unusual fossils that might otherwise have been destroyed.
Westbury and the wider Wiltshire Jurassic succession are particularly interesting to collectors because they provide access to fossil faunas from a time when marine reptiles swam through Jurassic seas and ammonites were abundant in the water column.
Fossil Type and Species
Laevaptychus latus is an aptychus, a fossil structure associated with ammonites. Aptychi are generally interpreted as paired plates that may have functioned as a protective operculum, closing the shell aperture when the animal withdrew into its body chamber, or as part of the jaw apparatus used in feeding. Because of this dual interpretation, they are often described as ammonite opercula or ammonite mouth parts.
This makes the fossil especially interesting, as it represents a more specialised part of ammonite anatomy rather than the more commonly collected outer shell. Aptychi are important because they help palaeontologists better understand how ammonites lived, fed, protected themselves, and evolved through time.
The name Laevaptychus is used for smooth or comparatively even aptychi forms, while latus refers to a broad form. Fossils of this type are associated with Jurassic ammonites and are often found separately from the main ammonite shell, making complete and identifiable examples desirable to collectors.
Morphology and Collector Appeal
Laevaptychus aptychi are typically recognised by their flattened plate-like shape, smooth to subtly textured surface, and association with ammonite cephalopods. Depending on preservation, the fossil may show a broad outline, natural curvature, growth lines, fine surface detail, or mineralised structure. These features give it a very different appearance from a coiled ammonite, while still linking it directly to ammonite biology.
This specimen has strong collector appeal because ammonite mouth parts and opercula are much less commonly offered than standard ammonite shells. It is a superb example for anyone building a more complete ammonite or Jurassic fossil collection, as it shows an anatomical feature that is often missing from displays focused only on shell forms.
A fossil such as this is also excellent for educational use. It helps demonstrate that ammonites were complex animals with soft bodies, jaws, chambers, shells, and protective structures, rather than simply decorative spiral fossils. For collectors of British Jurassic material, a genuine Laevaptychus latus from the Kimmeridge Clay Formation is a distinctive and unusual specimen.
Depositional Environment
During the Kimmeridgian, the Westbury area formed part of a marine basin where fine mud settled slowly onto the seabed. Ammonites lived in the surrounding water column, using their chambered shells to control buoyancy while feeding as active predators or scavengers. When ammonites died, their shells and associated body parts could sink to the seabed and become buried within the soft clay-rich sediment.
The Kimmeridge Clay environment was particularly favourable for preserving marine fossils because of its fine sediment and occasional low-oxygen seabed conditions. These settings helped reduce disturbance by scavengers and allowed some delicate or unusual remains to fossilise. This gives the specimen a direct connection to the ancient Jurassic sea that once covered Wiltshire.
Authenticity and Display
All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. This Laevaptychus latus aptychus fossil is supplied with a lifetime guarantee generic COA card for confidence and peace of mind.
Full sizing: please see photo.
The fossil shown in the photograph is the actual specimen you will receive. This rare and genuine Upper Jurassic Laevaptychus latus ammonite operculum from the Kimmeridge Clay Formation of Westbury, Wiltshire, UK is a superb addition to a fossil collection, natural history cabinet, geology teaching set, Jurassic display, or collection of rare British ammonite-related fossils.
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