Rare Mercaticeras alphacarinitus Ammonite Fossil, Lower Toarcian Stage Jurassic, Authentic Italian Collectors Specimen with COA

Description

Genuine Jurassic Ammonite Fossil

This listing offers a genuine Mercaticeras alphacarinitus Ammonite Fossil from the Lower Toarcian Stage of the Early Jurassic period, discovered in Italy. Ammonites were marine cephalopods within the subclass Ammonoidea and order Ammonitida, closely related to squid and cuttlefish. Their spiral, chambered shells are among the most iconic fossils, highly prized for their scientific and visual significance. This specimen has been carefully selected for its quality and preservation, with photographs showing the actual fossil you will receive. A 1 cm scale cube is included for accurate sizing.

Geological Context – Lower Toarcian, Jurassic

The fossil originates from the Lower Toarcian, dating back approximately 182 million years. This was a time of significant climatic and evolutionary change, marked by the Early Toarcian Oceanic Anoxic Event. The marine strata of Italy from this interval are well known for their ammonite faunas, preserved within fine-grained sediments deposited in shallow to moderately deep marine environments.

The Lower Toarcian is one of the most studied stages in ammonite biostratigraphy, as ammonite species are used extensively as index fossils. They provide precise markers for biozones, allowing geologists to correlate Jurassic rock sequences across large regions. Fossils such as Mercaticeras alphacarinitus are therefore not only collectible specimens but also important scientific tools.

Species Profile – Mercaticeras alphacarinitus

The species Mercaticeras alphacarinitus belongs to the family Hildoceratidae, within the superfamily Hildoceratoidea. Members of this family are known for their compressed shells, distinctive ribbing, and elegant coiling. Mercaticeras species in particular are widely recognised as zonal markers within the Lower Toarcian.

Key features of Mercaticeras alphacarinitus include:

• A compressed planispiral shell with moderately evolute coiling.
• Regular ribbing that strengthens towards the outer flanks and venter.
• A distinctive keel or carina along the venter, giving the species its name “alphacarinitus.”
• Visible suture lines marking the complex internal divisions of the shell chambers.

These characteristics make M. alphacarinitus an identifiable and scientifically valuable ammonite for both research and collection purposes.

Paleoenvironment and Importance

During the Early Jurassic, the region of Italy where this ammonite was found was submerged beneath warm epicontinental seas. Ammonites like Mercaticeras alphacarinitus thrived as active swimmers in these waters, preying on smaller organisms. Upon death, their shells sank to the seafloor where they were rapidly buried by fine sediments, preserving them for millions of years.

The stratigraphic importance of this ammonite lies in its restricted distribution within Lower Toarcian biozones. As a zonal fossil, M. alphacarinitus is essential for defining precise intervals in the Toarcian stage, helping paleontologists reconstruct Jurassic marine environments and evolutionary history.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and come with a Certificate of Authenticity. This ammonite fossil is an authentic relic of Earth’s history, not a replica or reproduction, preserved in stone for nearly 182 million years.

Perfect for Collectors and Enthusiasts

This Mercaticeras alphacarinitus ammonite fossil from Italy makes an excellent addition to any fossil collection or educational display. Its combination of scientific significance, geological value, and striking natural form ensures it will be a prized specimen for collectors, geology students, and natural history enthusiasts alike.

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