Rare Aspidoceras rogiznicensis Ammonite Fossil, Lower Tithonian Stage Late Jurassic, Authentic Madagascar Collectors Specimen with COA

Description

Authentic Jurassic Ammonite Fossil

This listing offers a genuine Aspidoceras rogiznicensis Ammonite Fossil from the Lower Tithonian Stage of the Late Jurassic, collected in Madagascar. Ammonites were extinct marine molluscs of the subclass Ammonoidea, closely related to squid and cuttlefish. Their chambered, spiral shells make them some of the most recognisable fossils in the world, prized by collectors and vital to paleontology. The photographs show the exact ammonite you will receive, with a 1 cm scale cube included for accurate size reference.

Geological Context – Lower Tithonian, Jurassic

The Tithonian Stage, dating to around 152–145 million years ago, represents the final stage of the Jurassic period, directly before the Cretaceous. The Lower Tithonian, from which this specimen originates, was a time of high ammonite diversity. Madagascar, positioned in the southern supercontinent Gondwana, was surrounded by shallow, tropical seas that offered ideal conditions for marine life and exceptional fossil preservation.

Ammonites like Aspidoceras rogiznicensis are significant as index fossils because of their relatively short evolutionary range. Their widespread occurrence across different marine environments allows geologists to date rock layers precisely and to correlate them with equivalent deposits in other regions of the world.

Species Profile – Aspidoceras rogiznicensis

The species Aspidoceras rogiznicensis belongs to the family Aspidoceratidae, within the superfamily Perisphinctoidea and order Ammonitida. Ammonites of this genus are known for their robust shells and ornate ornamentation, making them both scientifically valuable and aesthetically appealing.

Key identifying features of Aspidoceras rogiznicensis include:

• A thick, strongly ribbed shell with coarse ornamentation.
• Tubercles (rounded nodes) positioned on the flanks, a typical characteristic of Aspidoceratidae.
• Wide, involute whorls with a strong presence in cross-section.
• A broad venter with prominent ribbing extending across it.
• Complex sutures that mark the chamber divisions inside the shell.

These traits distinguish A. rogiznicensis from other ammonite genera and make it a diagnostic species for the Lower Tithonian ammonite faunas of Gondwana.

Paleoenvironment and Scientific Importance

During the Jurassic, the shallow tropical seas surrounding Madagascar provided rich ecosystems in which ammonites like Aspidoceras rogiznicensis thrived. These cephalopods lived as nektonic predators, actively swimming and preying on smaller marine invertebrates. After death, their shells sank to the seabed, where rapid burial in fine sediments preserved them for over 150 million years.

The importance of Aspidoceras rogiznicensis lies in its role as a biozonal marker within the Lower Tithonian Stage. Its unique morphology and limited stratigraphic range make it an invaluable fossil for refining the geological timescale, while also providing insight into evolutionary trends during the final stages of the Jurassic.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and include a Certificate of Authenticity. This ammonite is not a replica or reproduction but a true relic of Earth’s Jurassic seas, preserved naturally over millions of years.

A Collector’s and Display Fossil

This Aspidoceras rogiznicensis ammonite fossil from the Lower Tithonian of Madagascar is a remarkable addition to any fossil collection or natural history display. With its robust ribbing, striking tubercles, and scientific value, it is an outstanding specimen for collectors, educators, and enthusiasts of Earth’s history.

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