Rare Leptosphinctes subfurcatum (juvenile) Ammonite Fossil, Middle Bajocian Stage Jurassic, Authentic Normandy France Specimen

Description

Authentic Jurassic Ammonite Fossil

This listing features a genuine Leptosphinctes subfurcatum (juvenile) Ammonite Fossil from the Middle Bajocian Stage of the Jurassic, collected in Normandy, France. Ammonites are an extinct group of marine cephalopods within the subclass Ammonoidea, related to squid and cuttlefish. Their spiral, chambered shells allowed them to control buoyancy, making them agile predators in the oceans of the Mesozoic Era. This specimen represents a juvenile stage, displaying the delicate features of early growth. The photos show the exact fossil you will receive, with a 1 cm scale cube for size reference.

Geological Context – Middle Bajocian, Jurassic

The Bajocian Stage spans approximately 170–168 million years ago within the Middle Jurassic. It was a time when shallow seas extended across Europe, providing rich marine environments where ammonites flourished.

Normandy is renowned for its Jurassic outcrops, particularly in Calvados and surrounding regions, where marine sediments preserve diverse ammonite assemblages. These deposits are key fossiliferous sites for paleontological research, offering insight into the biodiversity and stratigraphy of the Middle Jurassic seas. Ammonites like Leptosphinctes subfurcatum serve as important index fossils, enabling geologists to date and correlate rock layers across wide regions.

Species Profile – Leptosphinctes subfurcatum (juv.)

The species Leptosphinctes subfurcatum belongs to the family Perisphinctidae, within the superfamily Perisphinctoidea and order Ammonitida. Ammonites of this family are noted for their evolute shells and characteristic ribbing patterns, which make them highly recognisable.

Key features of Leptosphinctes subfurcatum in juvenile form include:

• A relatively evolute shell, exposing inner whorls.
• Fine but well-defined ribs, often bifurcating as they cross the flanks.
• A moderately wide umbilicus, typical of perisphinctid ammonites.
• A smooth, rounded venter across which the ribs continue uninterrupted.
• Proportions characteristic of early growth stages, showing delicate features before the adult morphology fully develops.

These features make the species highly useful for stratigraphic classification and offer fascinating insights into ammonite ontogeny (growth stages).

Paleoenvironment and Scientific Importance

During the Bajocian, Normandy lay beneath warm, shallow seas linked to the vast Tethys Ocean. These seas were rich in marine life, from ammonites and belemnites to bivalves, crinoids, and marine reptiles. Ammonites like Leptosphinctes subfurcatum thrived as active, nektonic predators, feeding on smaller invertebrates while avoiding larger predators.

The preservation of juvenile specimens such as this is scientifically significant, as they reveal early shell development patterns. Ammonites are not only beautiful fossils but also critical tools in biostratigraphy, helping paleontologists refine the Jurassic timescale and understand evolutionary pathways.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and are accompanied by a Certificate of Authenticity. This provides assurance that your ammonite fossil is an authentic relic from the Jurassic seas of Normandy and not a reproduction or imitation.

A Collector’s and Display Fossil

This Leptosphinctes subfurcatum juvenile ammonite fossil from the Middle Bajocian of Normandy, France is a superb example for collectors, educators, and natural history enthusiasts. Its delicate ribbing, juvenile form, and provenance from one of Europe’s most celebrated fossil regions make it both scientifically valuable and visually captivating.

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