RARE Okaites rjasanensis iridescent Fossil Ammonite Callovian Jurassic Russia

Description

Rare Okaites rjasanensis Iridescent Fossil Ammonite from Russia

Presented here is a rare Okaites rjasanensis iridescent ammonite fossil from the Callovian stage of the Jurassic period, discovered in the fossil-rich deposits of Ryazan, Russia. This striking specimen, dating to approximately 165 – 161 million years ago, showcases the exceptional preservation for which Russian ammonite sites are renowned. The surface shimmers with natural iridescence, revealing the nacre of the ancient shell and creating a rainbow effect that enhances its visual appeal.

The fossil is shown with a 1 cm scale cube for precise sizing, and the specimen in the photographs is the exact fossil you will receive. As with all our offerings, it comes complete with a Certificate of Authenticity, guaranteeing its genuineness and provenance.

Geological Context

This ammonite originates from the Callovian stage, part of the Middle Jurassic. During this period, much of what is now Russia was submerged beneath shallow epicontinental seas, providing ideal conditions for marine life. Fine sediments settled over the seafloor, capturing and preserving ammonites, belemnites, crinoids, and other marine organisms in extraordinary detail.

The Ryazan region has long been recognized by paleontologists for its fossil-bearing strata. The local geology consists of calcareous clays and limestones deposited in stable marine shelf environments. These conditions often led to remarkable preservation of ammonite nacre, resulting in the distinctive iridescence seen in this specimen.

Scientific Classification

• Species: Okaites rjasanensis
• Order: Ammonitida
• Superfamily: Perisphinctoidea
• Family: Oppeliidae

This species belongs to the Oppeliidae, a family of ammonites distinguished by their finely ribbed shells and moderately involute coiling. Members of this group were important components of Jurassic marine ecosystems and are also widely used in biostratigraphy, providing key data for the dating and correlation of Jurassic sedimentary sequences.

Morphological Features

The Okaites rjasanensis specimen displays classic traits of the genus:

• Planispiral coiling with well-exposed whorls.
• Fine, regular ribbing across the surface, a diagnostic feature of the Oppeliidae.
• A compressed shell form with a strong suture pattern.
• Areas of natural iridescence where nacre has been preserved, producing a rainbow-like play of colours.

These features not only define the fossil’s scientific importance but also enhance its aesthetic and collectible value.

Paleoenvironment and Ecology

The depositional setting of this ammonite was a warm shallow sea, rich in marine biodiversity. Ammonites such as Okaites were active predators, likely feeding on small fish, plankton, and crustaceans, while themselves serving as prey for larger marine reptiles and cephalopods. Their abundance and diversity in Jurassic seas reflect their evolutionary success and ecological importance.

The fine-grained sediments of the Ryazan area created low-oxygen conditions that reduced decay and scavenging, allowing exceptional preservation of ammonite shells, including nacreous layers that today give these fossils their iridescent brilliance.

Collector and Display Value

This Okaites rjasanensis iridescent ammonite is both a scientifically significant fossil and a captivating display specimen. The preservation of shell detail, coupled with the shimmering iridescence, makes it a highly desirable acquisition for collectors of Jurassic ammonites. It is equally suitable for educational purposes or as a centrepiece in a display collection.

Its provenance from the well-documented fossil beds of Ryazan, Russia, enhances its authenticity and desirability, while its natural aesthetic appeal makes it an object of fascination even beyond the scientific community.

Key Features

• Species: Okaites rjasanensis
• Age: Middle Jurassic, Callovian stage (approx. 165 – 161 million years old)
• Provenance: Ryazan, Russia
• Family: Oppeliidae, Superfamily Perisphinctoidea
• Distinctive ribbing and compressed whorl structure
• Beautiful natural iridescence across the shell surface
• Supplied with a Certificate of Authenticity
• Exact specimen shown in the photos is the one supplied

This is a rare chance to own a genuine Okaites rjasanensis ammonite fossil from Russia—an authentic relic of the Jurassic seas, uniting geological history, natural artistry, and enduring scientific value.