RARE Lobolytoceras siemansi Fossil Ammonite Jurassic Toarcian Somerset UK Genuine Specimen

Description

Rare Lobolytoceras siemansi Fossil Ammonite from Somerset, UK

This listing offers a rare and genuine Lobolytoceras siemansi Fossil Ammonite, discovered in the historic Jurassic beds of South Petherton, Ilminster, Somerset, United Kingdom. Dating from the Toarcian stage of the Jurassic period, this ammonite is an outstanding example of an uncommon genus and species, combining both rarity and exceptional geological importance. With its distinctive morphology and provenance from the world-renowned Ilminster fossil localities, it represents a remarkable addition to any serious fossil collection.

Every fossil we sell is carefully chosen, and the photographs provided show the exact specimen you will receive. A 1 cm scale cube is included for precise measurement. All of our fossils are 100% authentic specimens and are supplied with a Certificate of Authenticity for complete assurance.

Geological Context and Provenance

This ammonite originates from the Toarcian stage of the Lower Jurassic, approximately 182 – 174 million years ago. The fossil-rich beds around Ilminster and South Petherton are globally significant, forming part of the Beacon Limestone Formation, which has yielded some of the finest ammonite assemblages in the world.

The Toarcian stage was a time of major marine biodiversity, but also one marked by environmental shifts, including widespread oceanic anoxic events. Ammonites such as Lobolytoceras siemansi provide valuable evidence for interpreting these paleoenvironmental changes, making them crucial for both scientific research and biostratigraphy.

Scientific Classification and Identification

This specimen is identified as Lobolytoceras siemansi, belonging to the family Lytoceratidae, within the superfamily Lytoceratoidea and order Ammonitida. Members of the Lytoceratidae are recognised by their evolute shell design, delicate whorl structure, and extremely intricate suture patterns.

The genus Lobolytoceras is considered relatively rare compared with other ammonites of the same interval, and siemansi is one of the more sought-after species. Its occurrence within the Toarcian beds of Somerset makes it an important reference fossil for correlating rock layers across Europe.

Morphology and Distinctive Features

The morphological features of Lobolytoceras siemansi include:

• Evolute shell coiling, where all whorls are exposed and visible.
• Complex, ornate suture patterns, with deeply indented lobes and saddles.
• Slender and graceful whorl cross-sections, giving the ammonite an elegant appearance.

These traits not only give the fossil strong visual appeal but also highlight adaptations for efficient swimming and buoyancy control in Jurassic seas. The complex sutures, in particular, are a hallmark of the Lytoceratidae, making this specimen both diagnostic and scientifically significant.

Depositional Environment

The Ilminster region of Somerset was part of a shallow, subtropical sea during the Jurassic. Fine-grained limestones and mudstones were deposited in quiet marine conditions, preserving ammonites and other organisms in remarkable detail. These rocks are internationally renowned, and ammonites from this locality are prized by collectors for both their scientific relevance and their natural beauty.

The South Petherton beds specifically are a classic source of Toarcian ammonites, known for their variety and preservation. This specimen of Lobolytoceras siemansi is a superb example from this important site.

Collectible and Scientific Importance

As a rare ammonite species from a world-class fossil locality, Lobolytoceras siemansi is a highly collectible specimen. Its rarity, distinctive morphology, and provenance from Somerset’s Jurassic beds give it both display value and scientific importance. Ammonites of this type are sought after by museums, researchers, and private collectors alike, as they illuminate an important chapter in the evolutionary history of cephalopods.

Key Features of This Fossil

• Rare Lobolytoceras siemansi ammonite from South Petherton, Ilminster, Somerset, UK
• Jurassic (Toarcian stage), approx. 182 – 174 million years old
• Member of the Lytoceratidae family, with intricate suture patterns and evolute shell
• From the internationally significant Beacon Limestone Formation
• Supplied with a Certificate of Authenticity
• The exact specimen pictured is the one you will receive

This Lobolytoceras siemansi Fossil Ammonite is a rare and scientifically valuable specimen from one of the UK’s most important Jurassic fossil localities, making it an exceptional addition to any fossil collection.