Rare Olcostephanus asteria Ammonite Fossil, Upper Valanginian Stage Early Cretaceous, Authentic Agadir Morocco Collectors Specimen with COA

Description

Genuine Cretaceous Ammonite Fossil

This listing offers a genuine Olcostephanus asteria Ammonite Fossil from the Upper Valanginian Stage of the Early Cretaceous, discovered in the Agadir region of Morocco. Ammonites were extinct marine cephalopods within the subclass Ammonoidea, related to modern squid and cuttlefish. Their coiled, chambered shells are instantly recognisable and highly prized both by collectors and scientists. The photographs provided show the exact specimen you will receive, with a 1 cm scale cube included for accurate sizing.

Geological Context – Upper Valanginian, Cretaceous

The Upper Valanginian, dating to around 135–133 million years ago, represents an important interval of the Early Cretaceous. During this time, shallow epicontinental seas covered much of North Africa, providing ideal habitats for ammonites and other marine organisms. The Agadir region of Morocco is particularly well known for its rich fossil deposits, which yield exceptionally preserved specimens of ammonites from this stage.

Ammonites like Olcostephanus asteria are crucial to stratigraphy because they are used as index fossils. Their rapid evolution and wide geographic distribution allow paleontologists to correlate rock layers and establish precise biozones, helping to build a clear geological timeline for the Early Cretaceous.

Species Profile – Olcostephanus asteria

The species Olcostephanus asteria belongs to the family Olcostephanidae, within the superfamily Perisphinctoidea and order Ammonitida. Members of this genus are characteristic ammonites of the Valanginian Stage and serve as important stratigraphic markers for this time interval.

Key identifying traits of Olcostephanus asteria include:

• A moderately evolute shell, with inner whorls clearly visible within the umbilicus.
• Strong ribbing, often bifurcating as it crosses the flanks.
• A rounded venter lacking a prominent keel, distinguishing it from earlier Jurassic genera.
• Robust whorls with well-defined ornamentation.
• Complex suture lines that reveal the internal chamber structure of the shell.

These features make O. asteria both a scientifically valuable index fossil and a visually striking specimen for collectors.

Paleoenvironment and Scientific Importance

During the Early Cretaceous, the area that is now Morocco was covered by shallow seas connected to the Tethys Ocean. Ammonites like Olcostephanus asteria lived as active nektonic predators, swimming freely through the water column and preying upon small crustaceans, molluscs, and plankton. When they died, their shells sank to the seabed and were buried in marine sediments, preserving them for over 130 million years.

The scientific importance of O. asteria lies in its role as a defining species of the Valanginian ammonite biozones. Its presence enables geologists to date and correlate rock layers with precision, contributing significantly to our understanding of Early Cretaceous paleoenvironments and evolutionary trends.

100% Genuine with Certificate of Authenticity

All of our fossils are guaranteed 100% genuine specimens and are accompanied by a Certificate of Authenticity. This assures that your ammonite is an authentic Cretaceous fossil from Morocco and not a cast or reproduction.

A Collector’s and Display Fossil

This Olcostephanus asteria ammonite fossil from the Upper Valanginian of Agadir, Morocco is a superb addition to any fossil collection, natural history display, or educational resource. Its combination of aesthetic appeal, geological provenance, and scientific importance makes it a standout specimen for both seasoned collectors and new enthusiasts.

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