RARE Barroisiceras onilahyense Ammonite Fossil Coniacian Cretaceous Tulear Madagascar COA

Description

Barroisiceras onilahyense Ammonite Fossil

Presented here is a rare Barroisiceras onilahyense ammonite fossil from the Coniacian stage of the Late Cretaceous, discovered in Tulear, Madagascar. This fossil is an authentic marine relic dating back approximately 89–86 million years ago, during a time when the island of Madagascar lay within the tropical waters of the ancient Tethys Ocean. The exact specimen pictured will be supplied, photographed with a 1 cm scale cube for reference. Every fossil offered is guaranteed to be 100% genuine and is accompanied by a Certificate of Authenticity.

Geological Context – Coniacian of Madagascar

The Coniacian stage represents a critical subdivision of the Late Cretaceous, following the Turonian and preceding the Santonian. This period was characterised by global high sea levels and warm climates, creating extensive shallow marine environments ideal for ammonite proliferation.

The Tulear region of southwestern Madagascar is world-renowned for its Cretaceous fossil beds, which produce exceptionally preserved ammonites. These marine sediments consist largely of limestones and marls, deposited in shallow tropical seas that teemed with life. Ammonites like Barroisiceras onilahyense thrived in these environments, leaving behind fossils that serve as both beautiful specimens and important biostratigraphic markers.

Species Overview – Barroisiceras onilahyense

The genus Barroisiceras belongs to the order Ammonitida, superfamily Acanthoceratoidea, and family Collignoniceratidae. The species Barroisiceras onilahyense is distinctive for its large, robust shell structure, with moderately involute whorls and bold ribbing. These ribs often strengthen towards the outer whorl and accentuate the rounded venter, giving the fossil a highly sculptured appearance.

Morphological features include:

• Strongly ribbed ornamentation across the shell flanks
• Deeply impressed sutures with complex patterns
• A solid, durable shell structure, reflecting adaptation to open marine conditions
• Symmetry and coiling consistent with the genus, making it easily recognisable to specialists

These diagnostic traits make Barroisiceras onilahyense an excellent reference fossil for the Coniacian stage.

Paleontological and Scientific Significance

Barroisiceras onilahyense is not only prized for its visual appeal but also for its role as an index fossil. Its occurrence helps geologists and paleontologists correlate Coniacian deposits across different parts of the world, particularly in the Tethyan realm. The evolutionary adaptations displayed by this species, such as its reinforced ribbing and shell strength, suggest a lifestyle in open water environments where hydrodynamic efficiency was crucial.

The fossil record of Madagascar provides crucial insights into ammonite distribution during the Late Cretaceous, and specimens like this highlight the biodiversity of ammonite faunas in southern hemisphere marine basins.

Collector and Display Value

This Barroisiceras onilahyense ammonite is a significant acquisition for collectors of rare Madagascan fossils or for anyone seeking Coniacian ammonites. Its rarity, strong shell detail, and provenance make it a highly desirable specimen. Beyond its scientific value, its natural sculptural qualities and striking form make it an impressive display piece, suitable for both private and museum collections.

Guarantee of Authenticity

• Genuine Barroisiceras onilahyense ammonite fossil
• From the Coniacian stage of the Late Cretaceous, Tulear, Madagascar
• Supplied with a Certificate of Authenticity
• Exact specimen in photographs will be sent

This is a rare opportunity to own a scientifically important and visually striking Barroisiceras onilahyense ammonite fossil from Madagascar’s renowned Cretaceous beds. It represents a true piece of Earth’s evolutionary history preserved in stone.