Accardia (Planamatoceras) liebi Ammonite Fossil from Lower Aalenian Jurassic Morocco Authentic

Description

Geological Context

This authentic Accardia (Planamatoceras) liebi ammonite fossil originates from the Lower Aalenian Stage of the Middle Jurassic, dating back around 174 to 170 million years ago. It was discovered in the Middle Atlas region of Morocco, an area world-renowned for its rich fossil deposits. During the Aalenian, this region was covered by a warm, shallow epicontinental sea that supported diverse marine ecosystems, with abundant ammonites thriving in these environments. The fine sediments that accumulated on the seabed provided the conditions necessary for exceptional fossil preservation, making Moroccan ammonites highly sought after by collectors and researchers alike.

Taxonomic Classification

• Kingdom: Animalia
• Phylum: Mollusca
• Class: Cephalopoda
• Order: Ammonitida
• Superfamily: Stephanocerataceae
• Family: Otoitidae
• Genus: Accardia (Planamatoceras)
• Species: Accardia liebi

This genus represents a significant branch within the ammonites of the Jurassic, exhibiting morphological adaptations that help palaeontologists study evolutionary pathways and environmental changes in the Aalenian seas.

Morphological Features

The Accardia (Planamatoceras) liebi ammonite is characterised by its elegant, tightly coiled planispiral shell. Key features include:

• Moderately involute shell, where inner whorls are partly covered by the outer coils.
• Fine, regular ribbing that radiates across the flanks, sometimes branching as it reaches the outer margin.
• A rounded to slightly compressed venter (outer rim), giving the fossil a streamlined appearance.
• Detailed and intricate suture lines, typical of Jurassic ammonites, reflecting the internal septal walls that once divided the animal’s living chambers.

These features not only make the specimen visually appealing but also scientifically important for biostratigraphic correlation.

Depositional Environment

The fossil was preserved within marine limestone and marl sediments of the Middle Atlas Basin. During the Lower Aalenian, Morocco lay within the margins of the Tethys Ocean. The seas were nutrient-rich and supported flourishing populations of cephalopods, bivalves, and marine reptiles. Periods of calm deposition in relatively low-energy marine environments allowed delicate ammonite shells to be buried before being destroyed by currents or predators, resulting in fossils of remarkable clarity and form.

Scientific and Collector Significance

• Biostratigraphic Value – Accardia liebi is an important index fossil for the Lower Aalenian, helping geologists to correlate rock layers across different regions.
• Evolutionary Insight – Provides evidence of ammonite diversification during the Jurassic, especially within the family Otoitidae.
• Collector’s Appeal – Its symmetrical ribbing and classic Jurassic form make it a desirable specimen for display, teaching, or private collections.
• Educational Relevance – An ideal fossil for illustrating ammonite anatomy, Jurassic marine environments, and the principles of fossilisation.

Authenticity and Presentation

• This is a 100% genuine ammonite fossil, supplied with a Certificate of Authenticity.
• The exact specimen photographed is the one you will receive, ensuring transparency and uniqueness.
• A 1 cm scale cube is shown in the images for precise size reference.

This remarkable Accardia (Planamatoceras) liebi ammonite fossil from the Lower Aalenian of the Jurassic, Middle Atlas, Morocco, is a scientifically valuable and visually captivating piece. With its historical and natural significance, it is an outstanding addition for collectors, educators, and enthusiasts of Earth’s prehistoric past.