Rare Grammoceras thouarense Ammonite Fossil, Middle Toarcian Stage Jurassic, Authentic Aveyron France Collectors Specimen with COA

Description

Genuine Jurassic Ammonite Fossil

This listing presents a genuine Grammoceras thouarense Ammonite Fossil from the Middle Toarcian Stage of the Early Jurassic, discovered in Aveyron, France. Ammonites are extinct marine cephalopods of the subclass Ammonoidea, closely related to squid and cuttlefish. Their distinctive coiled, chambered shells are among the most iconic fossils, prized both for their natural beauty and for their significance in paleontology. The photographs provided show the exact ammonite you will receive, and a 1 cm scale cube is included for accurate sizing.

Geological Context – Middle Toarcian, Jurassic

The Middle Toarcian, approximately 178–177 million years ago, followed the dramatic Early Toarcian Oceanic Anoxic Event, a period of major climatic and ecological upheaval. During this interval, ammonites diversified rapidly, and their fossils became invaluable tools for geological dating. The fossil-rich beds of Aveyron in southern France preserve these ammonites in remarkable detail, offering a window into ancient marine ecosystems.

Ammonites such as Grammoceras thouarense are especially significant because they serve as index fossils. Their rapid evolutionary turnover and wide geographic spread enable scientists to establish precise ammonite biozones, which are used to date and correlate Jurassic strata across Europe.

Species Profile – Grammoceras thouarense

The species Grammoceras thouarense belongs to the family Graphoceratidae, within the superfamily Hildoceratoidea and order Ammonitida. This genus is highly characteristic of the Middle Toarcian ammonite faunas of Europe.

Key identifying features of Grammoceras thouarense include:

• A compressed, evolute shell form with whorls clearly visible in the umbilicus.
• Fine, closely spaced ribbing that runs elegantly across the flanks.
• A sharp keel along the venter, a typical feature of this genus.
• Intricate suture lines marking the chamber divisions of the internal shell.

These diagnostic traits make Grammoceras thouarense an excellent stratigraphic marker and a visually appealing ammonite for collectors.

Paleoenvironment and Scientific Importance

During the Middle Toarcian, the Aveyron region was submerged beneath shallow seas connected to the Tethys Ocean. Ammonites like Grammoceras thouarense thrived in these waters as nektonic predators, swimming actively in the water column and feeding on smaller invertebrates. When they died, their shells settled onto the seabed and were buried in fine sediments, where they fossilised over millions of years.

The scientific importance of Grammoceras thouarense lies in its restricted stratigraphic range, which makes it a key biozonal marker for the Middle Toarcian. Its presence allows for highly precise dating of Jurassic rock sequences and correlations across wide geographic areas. For collectors, it represents both a strikingly beautiful fossil and a specimen of genuine paleontological value.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and include a Certificate of Authenticity. This ensures that your ammonite is not a reproduction or cast but an authentic fossil preserved for nearly 180 million years.

A Collector’s and Display Fossil

This Grammoceras thouarense ammonite fossil from the Middle Toarcian of Aveyron, France is an outstanding addition for collectors, educators, and enthusiasts of natural history. Its elegant ribbing, geological provenance, and scientific value make it a standout specimen for display and study.

Scale Rule Squares / Cube = 1 cm. Please see listing photos for the full sizing of this exact specimen.