Diadochoceras nodocostatum Iridescent Ammonite Fossil Upper Aptian Cretaceous Madagascar Tulear

Description

This listing offers a striking Diadochoceras nodocostatum ammonite fossil from the Upper Aptian stage of the Early Cretaceous Period, approximately 115–112 million years old. Collected near Tulear, Madagascar, this ammonite displays remarkable iridescence, a feature highly prized by collectors. Specimens from this region are well known for their natural brilliance and scientific importance, making this ammonite an exceptional addition to any collection.

All of our fossils are 100% genuine specimens and are supplied with a Certificate of Authenticity. The exact fossil shown in the photographs is the one you will receive, with a 1 cm scale cube and rule squares provided for precise size reference.

Geological Context and Age

This ammonite comes from the Upper Aptian stage of the Early Cretaceous, dating back around 115–112 million years. During this period, Madagascar was situated along the margins of the Tethys Ocean, with shallow tropical seas covering much of the island’s western coastline. These warm, mineral-rich marine environments were ideal for ammonites and other invertebrates, and conditions of rapid burial allowed for exceptional preservation.

The deposits around Tulear in southwest Madagascar are world-renowned for producing ammonites with spectacular natural iridescence. This shimmering effect, caused by the preservation of the original aragonite shell layers, makes these fossils unique among ammonites worldwide.

Morphology and Distinctive Features

Diadochoceras nodocostatum belongs to the family Desmoceratidae, within the superfamily Desmoceratoidea of the order Ammonitida. The species is characterised by its robust, evolute shell, with rounded whorls and strong ribbing (costae) across the flanks. Distinctive nodules or tubercles occur along the ribbing, giving the shell a textured appearance.

This specimen displays both the ribbed ornamentation and iridescent preservation that define the species. The iridescence occurs due to light interference on the microscopic layering of the original shell, producing shimmering colours that change as the fossil is viewed from different angles. This rare feature makes Diadochoceras nodocostatum not only scientifically valuable but also visually captivating.

Scientific Importance

As a fossil from the Upper Aptian stage, Diadochoceras nodocostatum is significant in biostratigraphy, serving as a useful marker for correlating Early Cretaceous deposits across the Tethyan realm. Its robust ornamentation and distinctive nodules make it relatively easy to identify, which adds to its utility as a stratigraphic indicator.

The preservation of iridescence in Madagascan ammonites also provides valuable information about the original mineralogy of ammonite shells and the diagenetic processes that allowed such exceptional preservation. These fossils are frequently studied for both their palaeontological and mineralogical significance.

Collector and Display Value

This Diadochoceras nodocostatum ammonite fossil from Tulear, Madagascar, combines scientific importance with exceptional visual appeal. The natural iridescence enhances its aesthetic value, making it highly sought after by collectors worldwide. Each Madagascan ammonite is unique, and iridescent examples like this are particularly prized.

Whether displayed as a centrepiece fossil, used as an educational specimen, or added to a curated collection, this ammonite represents both a beautiful natural artwork and a tangible piece of Earth’s history. Its provenance from Tulear adds further prestige, as the region is globally recognised for its iridescent ammonites.

Your Guarantee of Authenticity

• 100% genuine Diadochoceras nodocostatum ammonite fossil from Tulear, Madagascar
• Geological age: Upper Aptian stage, Early Cretaceous (approx. 115–112 million years old)
• Distinctive preservation with natural iridescence
• Supplied with a Certificate of Authenticity
• Exact specimen shown in photographs (not a stock image)
• Scale cube and rule squares = 1 cm (see photos for accurate sizing)

This Diadochoceras nodocostatum iridescent ammonite fossil is a scientifically significant and visually stunning specimen from Madagascar’s Upper Aptian deposits. With its shimmering beauty, excellent provenance, and guaranteed authenticity, it is a superb addition to any fossil collection.