Description
Genuine Orthosphinctes ardesia inconditus Ammonite Fossil
This genuine Orthosphinctes ardesia inconditus ammonite fossil comes from the Upper Jurassic Kimmeridgian deposits of Le Bois Noir, Monoblet, Gard, France. It is a carefully selected marine fossil specimen from the Hypselocyclum Zone, an important biostratigraphic interval within the Kimmeridgian Stage. Ammonites were extinct marine cephalopods, related to modern squid, octopus and nautilus, and they are among the most important fossil groups for dating and correlating Jurassic marine rocks.
This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card. Full sizing can be seen in the photo. The fossil shown is the actual carefully chosen specimen you will receive, making it ideal for collectors who value accurately represented fossils with clear locality, age and zone information.
Upper Jurassic Kimmeridgian Geology
The Kimmeridgian is a stage of the Late Jurassic, dating to approximately 157.3 to 152.1 million years ago. During this time, large parts of what is now southern France were influenced by warm marine conditions along the margins of the ancient Tethys Ocean and connected European seas. Sediments deposited in these environments included limestones, marls and fossil-bearing marine beds, preserving a diverse range of ammonites, bivalves, brachiopods, echinoids, belemnites and other sea life.
The Hypselocyclum Zone is a recognised Kimmeridgian ammonite biozone used for identifying and correlating specific rock layers within the Upper Jurassic. Fossils from named biozones are especially desirable to collectors because they provide a more precise geological context than age alone. This makes the specimen particularly appealing for those interested in ammonite stratigraphy, Jurassic palaeontology and well-documented fossil localities.
Orthosphinctes ardesia inconditus Species Detail
Orthosphinctes is a genus of perisphinctid ammonite, a major group of Jurassic ammonites known for their coiled shells, ribbed ornament and importance in biostratigraphy. Orthosphinctes ardesia inconditus represents a more specific identified form within this group, making it an interesting specimen for collectors who specialise in Upper Jurassic ammonites.
Perisphinctid ammonites are often recognised by evolute shells, where the whorls do not overlap heavily and the inner coils remain visible. This open coiling, combined with ribbed ornamentation, gives many specimens a highly attractive and classic Jurassic ammonite appearance. Orthosphinctes belongs within the order Ammonitida and is associated with the family Perisphinctidae, one of the most characteristic ammonite families of the Late Jurassic seas.
Ammonite Morphology and Features
Orthosphinctes ammonites typically display a planispirally coiled shell with strong ribbing across the flanks. The ribs may divide or branch as they pass from the inner part of the whorl toward the outer margin, a feature often seen in perisphinctid ammonites. Depending on preservation, this specimen may show the natural whorl shape, rib pattern, inner coils, outer body chamber or original matrix from the Kimmeridgian marine deposit.
Like all ammonites, Orthosphinctes had a shell divided internally into chambers. The living animal occupied the final body chamber, while earlier chambers helped regulate buoyancy in the water column. The internal suture lines, formed where chamber walls met the outer shell, are one of the defining scientific features of ammonites. These details, together with shell shape and ribbing, help palaeontologists distinguish different genera, species and stratigraphic forms.
Ancient Jurassic Marine Environment
This ammonite lived in a warm Late Jurassic sea rich in marine life. Orthosphinctes ardesia inconditus would have been part of an active marine ecosystem, moving through the water as a cephalopod predator or scavenger. It shared its environment with other ammonites, belemnites, bivalves, brachiopods, echinoids, gastropods and fish.
The marine deposits around Le Bois Noir, Monoblet, record ancient sea-floor conditions in what is now the Gard region of southern France. Fine sediment, carbonate mud and shell debris accumulated over time, gradually burying the remains of marine organisms. Over millions of years, these sediments hardened into rock, preserving fossils such as this ammonite as natural records of the Jurassic seas.
Le Bois Noir, Monoblet, Gard Locality
Le Bois Noir at Monoblet in Gard, France, is a locality associated with fossiliferous Upper Jurassic deposits. Fossils from this region are valued for their combination of attractive preservation, precise stratigraphic information and connection to the classic Jurassic marine successions of southern France. The named Hypselocyclum Zone adds further scientific and collectable interest, placing the fossil within a defined Kimmeridgian ammonite interval.
For collectors, locality information is an important part of a fossil’s value. This specimen is not only an attractive ammonite, but also a documented geological piece from a recognised French Jurassic setting.
Collectable French Jurassic Ammonite
This Orthosphinctes ardesia inconditus ammonite fossil is an excellent addition to any collection of Jurassic fossils, French ammonites, Kimmeridgian fossils, Perisphinctidae ammonites or marine invertebrate specimens. Its Upper Jurassic age, Hypselocyclum Zone association and Le Bois Noir provenance make it a desirable fossil for display, study and natural history collecting.
Supplied with a Certificate of Authenticity lifetime guarantee generic card, this genuine Orthosphinctes ardesia inconditus ammonite from Le Bois Noir, Monoblet, Gard, France, is a collectable example of a Late Jurassic marine fossil from one of Europe’s classic ammonite-bearing successions.
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