Olcostephanus asterias Ammonite Fossil Upper Valanginian Cretaceous Morocco Genuine Certified

Description

Genuine Olcostephanus asterias Ammonite Fossil from Morocco

This authentic Olcostephanus asterias ammonite fossil originates from the Upper Valanginian stage of the Early Cretaceous, dating to around 136–132 million years ago. Collected near Agadir, Morocco, this remarkable specimen offers collectors, researchers, and enthusiasts a chance to own a genuine relic from the ancient seas of the Early Cretaceous period. Every fossil we supply is carefully selected and comes with a Certificate of Authenticity, ensuring its scientific and collectible value. The exact specimen pictured is the one you will receive, with the scale cube in the photograph representing 1 cm for accurate size reference.

Geological Age and Context – The Upper Valanginian

The Valanginian stage is a subdivision of the Early Cretaceous, representing an era of significant marine biodiversity and evolutionary development among ammonites. The Upper Valanginian saw widespread ammonite diversification, with genera such as Olcostephanus becoming key markers in stratigraphic studies. The marine deposits around Agadir are rich in limestone and marl layers, which were laid down in shallow epicontinental seas. These sediments created excellent conditions for fossil preservation, allowing us today to study ammonites in striking detail.

Scientific Classification

• Class: Cephalopoda
• Subclass: Ammonoidea
• Order: Ammonitida
• Superfamily: Perisphinctoidea
• Family: Olcostephanidae
• Genus: Olcostephanus
• Species: Olcostephanus asterias

Olcostephanus is one of the most recognisable ammonite genera of the Early Cretaceous. Its widespread occurrence across Europe, North Africa, and South America makes it a vital genus for stratigraphic correlation and paleoenvironmental reconstruction.

Morphology and Distinctive Features

The shell of Olcostephanus asterias is planispiral and strongly ribbed, with ribs that often radiate outward in a distinctive star-like pattern, which inspired the species name asterias (Greek for “star”). These ribs cross the whorl flanks and typically bifurcate, creating a striking ornamental effect. The whorls are evolute, meaning earlier coils remain visible, giving the ammonite a broad, open appearance.

The robust ribbing was not just aesthetic; it provided structural reinforcement for the shell, allowing the ammonite to withstand high pressures in marine environments. The complex suture lines—deeply folded patterns where internal walls met the outer shell—further strengthened the shell and are a hallmark of ammonite adaptation and evolutionary innovation.

Paleoenvironment of the Moroccan Seas

During the Early Cretaceous, Morocco lay within the northern margin of the ancient Tethys Ocean. The area around Agadir was covered by shallow, warm seas that supported abundant marine life. Ammonites such as Olcostephanus asterias thrived in this setting as agile, free-swimming predators, feeding on small crustaceans and other planktonic organisms. These ammonites played a critical role in the food web, serving as prey for larger marine reptiles such as ichthyosaurs and plesiosaurs.

The fossil-rich deposits of Morocco not only showcase ammonites but also yield bivalves, gastropods, and occasional marine reptile remains, painting a vivid picture of Early Cretaceous ecosystems.

Collectible and Scientific Importance

This Olcostephanus asterias ammonite fossil is more than a decorative piece—it is a scientifically significant specimen that reflects the evolutionary success of ammonites during the Early Cretaceous. Its distinctive ribbing makes it a particularly eye-catching example for collectors, while its precise age and species identification give it value for researchers and educators alike.

Whether displayed in a private collection, used for study, or given as a unique gift, this fossil provides a tangible connection to the ancient seas of Morocco. With its combination of striking preservation, geological importance, and certified authenticity, it represents both natural beauty and scientific heritage.