Description
Authentic Longaeviceras placentum Fossil Ammonite
This fine specimen is a Longaeviceras placentum fossil ammonite from the Upper Callovian Stage of the Jurassic Period, found at Marston Meysey, United Kingdom. Representing a species that flourished in the warm Jurassic seas around 164–161 million years ago, this ammonite captures the evolutionary diversity of the Cephalopoda and is an exceptional piece for collectors and enthusiasts of natural history.
Every specimen we provide is 100% genuine and comes with a Certificate of Authenticity. The photographs show the actual ammonite you will receive, with a scale cube marked in 1 cm squares to provide accurate sizing and proportion.
Geological Context
The specimen dates from the Upper Callovian Stage of the Middle Jurassic, a time when vast shallow seas covered much of present-day Europe. These marine environments were home to abundant ammonite species, which are now among the most important fossils for scientific study.
The Upper Callovian is a key stratigraphic stage, offering rich fossil assemblages that allow geologists to establish detailed correlations across Europe. Longaeviceras placentum is a notable ammonite from this period, serving as a valuable index fossil for refining Jurassic biozones. Its presence in the fossil record helps to establish the relative ages of sedimentary layers and aids in reconstructing ancient marine ecosystems.
Scientific Classification
- Species: Longaeviceras placentum
- Genus: Longaeviceras
- Family: Cardioceratidae
- Superfamily: Stephanoceratoidea
- Order: Ammonitida
- Class: Cephalopoda
- Age: Upper Callovian, Middle Jurassic (~164–161 million years ago)
- Locality: Marston Meysey, United Kingdom
Morphological Features
Longaeviceras placentum is characterised by its elegant coiled shell with distinct ribbing patterns. The ribs typically bifurcate or trifurcate as they extend outward, creating a striking ornamental appearance. Its whorls are moderately involute, with inner coils partly concealed, and the outer shell displays a well-defined keel.
Like other members of the Cardioceratidae, its sutures are complex, forming intricate patterns that enhance both its scientific interest and visual appeal. These features reflect its evolutionary adaptations and make the fossil a highly desirable addition to any collection.
Paleoenvironment and Ecology
During the Upper Callovian, the seas of what is now Britain were shallow, warm, and teeming with life. Longaeviceras placentum would have lived as a nektonic predator, swimming actively and using its tentacles to capture prey such as small crustaceans and fish. Its chambered shell, filled with gas and liquid, allowed it to regulate buoyancy and navigate efficiently within the water column.
The fine-grained marine sediments at Marston Massey created ideal conditions for fossil preservation. Rapid burial in anoxic conditions protected ammonite shells from decay and scavenging, ensuring that exquisite structural details remained intact over millions of years.
Collectability and Importance
This Longaeviceras placentum ammonite from Marston Meysey is a superb example of a Jurassic fossil, combining aesthetic beauty with geological significance. Its strong ribbing, finely detailed sutures, and stratigraphic importance as an index fossil make it a piece of enduring scientific and collector value.
- Type: Fossil Ammonite – Longaeviceras placentum
- Age: Upper Callovian, Jurassic (~164–161 million years ago)
- Origin: Marston Meysey, United Kingdom
- Scale Reference: 1 cm cube shown in photographs
- Authenticity: Guaranteed genuine with Certificate of Authenticity
- Specimen: The exact fossil pictured is the one you will receive
A genuine relic of Earth’s Jurassic seas, this ammonite is a remarkable specimen for collectors, students of paleontology, or anyone with an appreciation for the deep history of life preserved in stone.
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