Description
Offered here is a Rare 6″ Fossil Ammonite of Ptycholytoceras humile from the Toarcian Stage of the Lower Jurassic, collected from the classic ammonite-rich beds of Somerset, United Kingdom. This is a highly sought-after specimen due to its excellent preservation, elegant coiling, and scientific importance.
The specimen pictured is the exact ammonite you will receive. It has been carefully selected for both aesthetic and scientific quality.
Scale Rule Squares / Cube = 1cm — see the photo for full sizing.
Geological & Taxonomic Details:
- Species: Ptycholytoceras humile
- Fossil Type: Ammonite (extinct marine cephalopod)
- Geological Period: Jurassic
- Geological Stage: Toarcian (Lower Jurassic)
- Approximate Age: ~182 to 174 million years ago
- Locality: Somerset, England, UK
- Formation: Likely from the Upper Lias (Whitby Mudstone Formation)
- Order: Ammonitida
- Superfamily: Lytocerataceae
- Family: Lytoceratidae
- Described By: Commonly attributed to Neumayr, late 19th century
Morphology Features:
Ptycholytoceras humile is notable for its very evolute shell (meaning all whorls are visible), and broad, flat flanks with gently curved ribs and a shallow umbilicus. The venter (outer edge) is rounded, and the ribbing is subtle, often only lightly ornamented. The suture lines — a key identifier in ammonites — are complex and lobate, typical of the Lytoceratidae family.
This genus is known for its relatively graceful morphology, representing a transition between more primitive Jurassic forms and the highly ornamental ammonites of later periods.
Stratigraphy & Biozone:
While Ptycholytoceras itself is not a primary zone fossil, it is often found in association with index fossils of the Falciferum and Bifrons zones of the Middle Toarcian, making it a useful supporting species for biostratigraphic correlation across Europe.
Depositional Environment:
The ammonite was preserved in deep marine offshore mudstones, formed in a low-oxygen basin environment during a time of major climatic change known as the Toarcian Oceanic Anoxic Event (T-OAE). These conditions led to superb fossil preservation, especially for cephalopods, fish, and marine reptiles.
Scientific Significance:
Ammonites like Ptycholytoceras humile are critical to understanding Jurassic marine ecosystems, evolutionary radiation during the early Jurassic, and global anoxic events that shaped life in ancient oceans. This specimen is an excellent addition for both collectors and palaeontological reference.
Authenticity & Quality:
All of our fossils are 100% genuine specimens, responsibly sourced and professionally handled. A Certificate of Authenticity is provided with every order for provenance and assurance.
Whether you’re building a personal collection or sourcing for educational display, this Ptycholytoceras humile ammonite represents a rare and refined fossil from the iconic Jurassic heritage of Somerset.
Let us know if you’d like to include an educational display label or custom packaging.






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