Rare ACRIOCERAS TABARELLI Heteromorph Ammonite – Upper Barremian Cretaceous, South Atlas Morocco

Description

Featured here is an exceptional and rare fossil specimen of ACRIOCERAS TABARELLI, a striking heteromorph ammonite from the Upper Barremian Stage of the Lower Cretaceous. This authentic fossil was collected from the South Atlas region of Morocco, a renowned site for Cretaceous marine invertebrates.

Taxonomic Classification:

• Order: Ammonitida
• Superfamily: Ancyloceratoidea
• Family: Acrioceratidae
• Genus & Species: Acrioceras tabarelli

Geological Context:

• Period: Cretaceous
• Stage: Upper Barremian (approximately 126–125 million years ago)
• Formation: Marine carbonate or marl-limestone sequences of the Atlas region
• Depositional Environment: Shallow epicontinental marine basin influenced by periodic anoxic conditions. These ammonites lived in open marine settings and are often preserved in fine-grained sediment that allowed detailed preservation.

Morphological Features:

• Acrioceras tabarelli is a heteromorph ammonite characterised by loosely coiled helicoidal whorls, which transition into more straightened or hook-like shaft segments
• Prominent ribbing and tubercles along the flanks, with complex suture lines visible on well-preserved specimens
• The open coil and uncoiled segments are evolutionary adaptations, possibly influencing buoyancy or mobility in the water column

Scientific & Collector Significance:

• Heteromorph ammonites like Acrioceras are valuable in studying evolutionary trends and morphological experimentation during the Cretaceous ammonite radiation
• This species contributes to biozonation and regional stratigraphy within the Barremian marine sequences of northern Africa

Locality Information:

• South Atlas Mountains, Morocco – a prolific Cretaceous fossil-bearing region, particularly rich in ammonites, belemnites, and other marine fauna. The preservation is often exceptional due to fine-grained sediment and minimal tectonic disturbance.

Authenticity & Presentation:

All of our fossils are 100% Genuine Specimens and come with a Certificate of Authenticity. The listing includes photographs of the exact specimen you will receive. The scale rule cube = 1cm, with full sizing visible in the image.

This is a scientifically important and beautifully preserved example of a rare heteromorph ammonite, selected for its form and clarity. Ideal for fossil collectors, display, or anyone with a passion for unusual marine life from Earth’s distant past.

Add a unique evolutionary relic from the Lower Cretaceous seas to your collection today!