Perisphinctes Fossil Ammonite Upper Oxfordian Jurassic Madagascar – Genuine Authentic Prehistoric Marine Cephalopod with Certificate

Description

Stunning Jurassic Ammonite from Morondava, Madagascar

This listing presents a beautiful Perisphinctes fossil ammonite from the Upper Oxfordian stage of the Late Jurassic period, sourced from the well-known fossil beds of Morondava, Madagascar. Carefully chosen for its preservation, detail, and overall display quality, this specimen is an excellent example of a classic Jurassic cephalopod. The photographs show the exact fossil you will receive, allowing you to appreciate its intricate ribbing and elegant shell form.

Geological Age & Formation

Perisphinctes lived approximately 163.5 to 157.3 million years ago during the Upper Oxfordian stage of the Late Jurassic. At that time, the Morondava region was part of a shallow tropical sea teeming with marine life. Over millions of years, fine marine sediments gently buried the ammonite shells, preserving their distinctive patterns and shapes in exquisite detail. The fossil-rich deposits of Madagascar are particularly famous for producing ammonites with exceptional clarity of ornamentation and striking natural beauty.

Species Identification & Morphology

Belonging to the family Perisphinctidae within the superfamily Perisphinctoidea and order Ammonitida, Perisphinctes species are characterised by their evolute shells, where all whorls are visible from the side, and strong, regular ribbing. In many specimens, the ribs bifurcate (split) towards the venter, creating a symmetrical and aesthetically pleasing pattern. This example shows sharp ribbing and clear whorl definition, with well-preserved suture lines that highlight the complexity of its internal chamber structure.

These morphological traits were functional as well as decorative—the ribbing added strength to the shell, while the hydrodynamic shape allowed the animal to move efficiently through the water.

Collector Highlights

• Preservation: Excellent, with sharp ribbing and visible suture detail.
• Size Reference: Scale cube in photographs = 1 cm squares for precise measurement.
• Authenticity: 100% genuine fossil, supplied with a Certificate of Authenticity.
• Provenance: Discovered in the renowned Upper Oxfordian marine deposits of Morondava, Madagascar.
• Display Quality: A classic, elegant ammonite perfect for display in a collection, study, or educational setting.
• Rarity: While Madagascar produces ammonites, specimens of this quality and stage-specific provenance are always in demand.

Paleoenvironment & Scientific Importance

During the Upper Oxfordian, Perisphinctes ammonites thrived as nektonic predators, hunting small crustaceans, mollusks, and planktonic organisms. Their chambered shells (phragmocones) allowed precise buoyancy control by adjusting the gas and fluid within each chamber, enabling them to move vertically as well as horizontally in the water column.

In paleontology, Perisphinctes serves as an important index fossil for Oxfordian-aged strata, meaning its presence can help geologists date and correlate rock layers across different regions. The widespread distribution of this genus, combined with its distinctive and easily recognisable morphology, makes it highly valuable for biostratigraphic studies.

A Beautiful Piece of Jurassic History

This Perisphinctes fossil ammonite offers both aesthetic appeal and scientific significance, making it a standout choice for serious fossil collectors, geology enthusiasts, educators, or anyone wishing to own a unique and authentic relic from the Jurassic seas.

All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. The fossil pictured is the exact specimen you will receive.