Gruneria gruneri Ammonite Fossil Toarcian Jurassic Dorset UK Genuine Collectors Specimen

Description

Rare Gruneria gruneri Ammonite Fossil from Dorset, UK

This exceptional Gruneria gruneri ammonite fossil originates from the Toarcian Stage of the Early Jurassic, approximately 182–174 million years ago. Discovered on the world-renowned Jurassic Coast of Dorset, United Kingdom, this specimen represents a rare and scientifically important cephalopod. Beautifully preserved and presented with a 1cm scale cube for accurate size reference, the fossil offered here is exactly the specimen you will receive. All our fossils are 100% genuine and accompanied by a Certificate of Authenticity for complete assurance.

Geological Context

• Geological Period: Jurassic
• Stage: Toarcian (~182–174 million years ago)
• Location: Dorset, United Kingdom

The Toarcian Stage of the Early Jurassic was a dynamic interval characterised by widespread marine transgressions and environmental change, including the Toarcian Oceanic Anoxic Event, which profoundly influenced marine life. Dorset, part of the UNESCO Jurassic Coast World Heritage Site, preserves world-class fossiliferous strata, making it a significant area for studying ammonite evolution, stratigraphy, and marine paleoecology.

Scientific Classification

• Kingdom: Animalia
• Phylum: Mollusca
• Class: Cephalopoda
• Order: Ammonitida
• Superfamily: Hildoceratoidea
• Family: Hildoceratidae
• Genus: Gruneria
• Species: Gruneria gruneri

Morphological Features

This ammonite fossil showcases the diagnostic traits of Gruneria gruneri, including:

• Shell Form: Moderately involute with compact whorls.
• Ribbing: Strong, regular ribs extending across the flanks, often bifurcating towards the outer whorl.
• Keel: A distinct keel running along the venter, characteristic of the genus.
• Whorl Cross-Section: Compressed and sub-rectangular, providing excellent hydrodynamic efficiency for an active nektonic lifestyle.

These morphological features make Gruneria an important marker species for the Toarcian biozones, widely used in ammonite-based stratigraphy.

Paleoenvironment and Significance

During the Toarcian, Dorset and much of Europe lay beneath warm shallow seas, part of the epicontinental seaways of the Tethys Ocean system. Ammonites such as Gruneria were fast-swimming predators or opportunistic feeders, relying on their chambered shells for buoyancy control.

The genus Gruneria is of particular interest to paleontologists because it reflects evolutionary adaptations during a time of environmental stress and rapid faunal turnover. Its ribbing and keel structure highlight functional morphology linked to hydrodynamic stability in open-water marine settings.

As a stratigraphically significant genus, Gruneria gruneri assists in defining ammonite biozones within the Toarcian, making this fossil valuable for both research and collection.

Key Details

• Species: Gruneria gruneri
• Age: Toarcian Stage, Early Jurassic (~182–174 million years ago)
• Location: Dorset, United Kingdom
• Authenticity: Genuine specimen, Certificate of Authenticity included
• Sizing: Please refer to the scale cube in photos (1cm per square)

Collectability and Display Value

This rare Gruneria gruneri ammonite fossil is a highly desirable collector’s piece that combines scientific importance with natural beauty. Its strong ribbing, well-preserved form, and provenance from the iconic Jurassic Coast of Dorset make it a standout addition to any fossil collection.

Ideal for fossil collectors, geology enthusiasts, or as a unique natural history display, this specimen represents an ancient marine predator preserved for nearly 180 million years. Owning this fossil provides a direct connection to the rich evolutionary story of the Jurassic seas.