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 ammonite mouth part from the Kimmeridge Clay Formation of Water Park, Gloucestershire, UK. Dating to the Upper Jurassic, Kimmeridgian stage, this specimen is an unusual and highly collectable fossil linked to ammonites, the iconic extinct marine cephalopods that lived in ancient Jurassic seas. Unlike a standard coiled ammonite shell, an aptychus represents part of the animal’s functional anatomy, making it a fascinating specimen for collectors interested in ammonite biology, rare fossil material, and British Jurassic 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 Water Park, Gloucestershire, a classic Upper Jurassic marine unit in the UK. The specimen is Kimmeridgian in age, dating to approximately 157 to 152 million years ago. During this time, much of southern and central Britain was covered by a warm to temperate marine sea, where fine muds, organic-rich sediments, and the remains of marine organisms accumulated on the seabed.
The Kimmeridge Clay Formation is one of Britain’s best-known Jurassic fossil-bearing deposits. It is famous for preserving ammonites, belemnites, bivalves, fish, marine reptiles, 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 many fossil remains, including more unusual ammonite-related parts such as aptychi.
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 ammonite withdrew into its body chamber, or as part of the jaw apparatus used in feeding. Because of this, they are commonly described as ammonite opercula or ammonite mouth parts.
This makes the fossil especially interesting because it represents a specialised part of ammonite anatomy rather than the more commonly collected spiral shell. Aptychi help palaeontologists understand how ammonites lived, fed, protected themselves, and interacted with their marine environment.
The name Laevaptychus is used for comparatively smooth 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 identifiable examples particularly desirable to collectors.
Morphology and Collector Appeal
Laevaptychus aptychi are typically recognised by their flattened, plate-like shape, smooth to subtly textured surface, and close association with ammonite cephalopods. Depending on preservation, the fossil may show a broad outline, natural curvature, fine growth lines, 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 an excellent fossil for anyone building a more complete ammonite or Jurassic 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 ideal for educational use. It helps demonstrate that ammonites were complex animals with soft bodies, jaws, chambered shells, and possible 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 Water Park 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 clay-rich sediment.
The Kimmeridge Clay environment was especially favourable for preserving marine fossils because of its fine sediment and low-energy depositional setting. Occasional low-oxygen conditions helped reduce disturbance from scavengers and burrowing organisms, allowing some delicate or unusual remains to fossilise. This gives the specimen a direct geological link to the ancient Jurassic sea that once covered this part of Gloucestershire.
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 Water Park, Gloucestershire, 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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