Description
This listing offers a RARE fossil ammonite specimen of Acanthopleuroceras valdani, discovered in the Lower Pliensbachian (Early Jurassic) strata near Fresnay-le-Puceux, Calvados, Normandy, France. This strikingly ribbed ammonite represents a distinctive genus known from the Carixian substage and is highly prized by collectors for both its scientific value and aesthetic appeal.
As with all our items, this fossil is 100% genuine and comes with a Certificate of Authenticity. You will receive the exact specimen pictured in the listing. Refer to the photo with the 1cm scale cube for exact sizing.
Fossil Overview:
- Species: Acanthopleuroceras valdani
- Common Name: Fossil Ammonite
- Geological Period: Jurassic
- Stage: Lower Pliensbachian (~190 to 183 million years ago)
- Zone: Uptonia jamesoni Zone (Carixian Substage)
- Location: Fresnay-le-Puceux, Calvados, Normandy, France
- Preservation: External mould in limestone or marl, showcasing full whorl detail
Geological & Depositional Environment:
During the Early Jurassic, much of northern France was submerged beneath a warm, shallow epicontinental sea. The fossil-bearing layers at Fresnay-le-Puceux are part of the Lower Jurassic marine transgressive sequences, composed primarily of grey marls and limestones deposited in a quiet offshore shelf environment.
These conditions allowed for excellent preservation of ammonites like Acanthopleuroceras, whose ribbed shells settled into fine sediments after death.
Biozone & Stratigraphic Significance:
Acanthopleuroceras valdani is a marker species of the Lower Pliensbachian, Jamesoni Zone, specifically within the Carixian substage, which is widely used in European ammonite biostratigraphy. Its distinctive morphology helps refine regional correlations in Jurassic stratigraphic studies.
Taxonomy & Classification:
- Phylum: Mollusca
- Class: Cephalopoda
- Subclass: Ammonoidea
- Order: Ammonitida
- Superfamily: Eoderoceratoidea
- Family: Polymorphitidae
- Genus: Acanthopleuroceras
- Species: valdani
Morphological Features:
- Strong, evenly spaced radial ribs with tubercles or small spines on the ventrolateral area
- Evolute coiling with visible inner whorls
- Deep umbilicus
- Typical of a nektonic, free-swimming marine predator
These features suggest it lived actively in the water column, preying on smaller marine organisms. The pronounced ribbing likely added structural strength and may have played a role in hydrodynamics or species recognition.
Notable Information:
- Acanthopleuroceras is relatively rare and highly sought after in ammonite collections
- Well-defined ribbing makes it an excellent study specimen for ammonite morphology
- Found in classic Jurassic sites of northern France
- A perfect piece for display, teaching, or serious fossil collections
Why Buy From Us?
- Every fossil is a genuine natural specimen
- Comes with a Certificate of Authenticity
- The exact item shown in photos is the one you’ll receive
- Prompt, secure shipping and professional service
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