Description
Rare Ptychophylloceras (Semisulcatoceras) silesiacum Ammonite Fossil
This exquisite Ptychophylloceras (Semisulcatoceras) silesiacum ammonite fossil comes from the renowned Lacisterne Boisset region in Gard, France, and dates back to the Berriasian Stage of the Early Cretaceous, approximately 145–139 million years ago. A genuine specimen of exceptional scientific and collector’s value, it is presented exactly as photographed, with a 1cm scale cube for precise sizing. Every fossil in our collection is guaranteed authentic and supplied with a Certificate of Authenticity.
Geological Context
- Geological Period: Cretaceous
- Stage: Berriasian (earliest stage of the Cretaceous)
- Age: ~145–139 million years ago
- Location: Lacisterne Boisset, Gard, France
The Berriasian Stage marks the very beginning of the Cretaceous, following the close of the Jurassic. It represents a key evolutionary interval where ammonite faunas diversified into distinctive lineages that are now used by geologists as index fossils for international stratigraphic correlation. The rich fossil beds of southern France are world-famous for their preservation of these ammonites, providing a glimpse into marine ecosystems at the dawn of the Cretaceous.
Scientific Classification
- Kingdom: Animalia
- Phylum: Mollusca
- Class: Cephalopoda
- Order: Ammonitida
- Superfamily: Phyllocerataceae
- Family: Phylloceratidae
- Genus: Ptychophylloceras
- Subgenus: Semisulcatoceras
- Species: Ptychophylloceras (Semisulcatoceras) silesiacum
Morphological Features
This specimen exhibits the defining characteristics of Phylloceratidae ammonites:
- Shell Form: Smooth, involute, and elegant, with a narrow umbilicus.
- Surface Ornamentation: Subtle ribbing or sulcation, more subdued compared to ribbed ammonites, giving it a refined appearance.
- Whorl Section: Slightly compressed with gently rounded flanks.
- Suture Line: Intricately foliated, highly diagnostic of Phylloceratidae, and useful for precise taxonomic identification.
The subgenus Semisulcatoceras is known for its distinctive ornamentation with faint grooves, which separate it from other Ptychophylloceras representatives.
Paleoenvironment and Significance
During the Berriasian, the region of present-day southern France was submerged under the warm waters of the Tethys Ocean, a shallow marine environment teeming with life. Ammonites such as Ptychophylloceras were nektonic predators or opportunistic feeders, capable of active swimming using jet propulsion, while their chambered shells allowed for buoyancy regulation.
This species is particularly significant because it represents one of the more elegant forms of early Cretaceous phylloceratids, a lineage considered ancestral to many later ammonite groups. Its smooth, less ornate shell structure contrasts with heavily ribbed genera, reflecting ecological diversity within ammonite communities of the time.
As an index fossil, Ptychophylloceras (Semisulcatoceras) silesiacum aids geologists in dating and correlating marine strata, making it both scientifically valuable and highly desirable among collectors.
Key Details
- Species: Ptychophylloceras (Semisulcatoceras) silesiacum
- Age: Early Cretaceous, Berriasian (~145–139 million years ago)
- Location: Lacisterne Boisset, Gard, France
- Authenticity: Guaranteed genuine with Certificate of Authenticity
- Sizing: Displayed with 1cm scale cube in photos for reference
Collectability and Display Value
This rare ammonite fossil represents not only an ancient marine predator but also a crucial marker in the evolutionary story of cephalopods. Its elegant smooth whorls and intricate suture pattern make it a visually striking specimen, while its geological and scientific context ensure it holds strong educational and research importance.
Perfect for discerning fossil collectors, academic study, or display in a private collection, this specimen from the earliest stage of the Cretaceous is a genuine link to Earth’s deep history, preserved for over 140 million years.
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