VERY RARE Fossil Ammonites Kossmatia & Pseudotissotia – Barremian, Cretaceous – Riassin, Russia – Alice Purnell Collection

Description

VERY RARE FOSSIL AMMONITES – KOSSMATIA & PSEUDOTISSOTIA

Geological Age: Barremian Stage (~129–125 million years ago)

Locality: Riassin, Russia

Stratigraphy: Lower Cretaceous Marine Deposits

Collection: Alice Purnell Collection

Authenticity: Supplied with Certificate of Authenticity

An extraordinary specimen pairing two very rare Lower Cretaceous ammonite genera—Kossmatia and Pseudotissotia—from the Barremian marine strata of Riassin, Russia. Fossils of this calibre and locality are infrequently seen on the collector’s market. This is a curated piece from the Alice Purnell Collection, and includes a clear photo of the actual specimen, with 1cm scale cubes for accurate size estimation.

GEOLOGICAL CONTEXT & CLASSIFICATION:

• Species: Kossmatia sp. & Pseudotissotia sp.
• Order: Ammonitida
• Superfamily: Acanthoceratoidea (tentative for Pseudotissotia)
• Family: Possibly Kossmatiidae and Tissotiidae
• Geological Stage: Barremian (Lower Cretaceous)
• Biozone Correlation: Likely associated with upper Barremian ammonite zones such as Gerardiceras or Nicklesia zones, depending on precise stratigraphy
• Depositional Environment:
• Epicontinental marine platform environment
• Likely mid-ramp to outer shelf settings based on regional palaeogeography
• Soft marl and limestone sequences with variable faunal assemblages

MORPHOLOGICAL FEATURES & NOTABILITY:

• Kossmatia is known for moderately evolute coiling, with ribbing and ventral keels—suggesting it was a nektonic ammonite adapted to open marine conditions
• Pseudotissotia exhibits more compressed forms with sharper ribbing, associated with fast-swimming adaptations
• These genera show evolutionary ties across the Barremian-Aptian boundary, and specimens with such completeness and association are extremely scarce
• The presence of two distinct genera on one specimen may suggest co-depositional taphonomy, which adds palaeoecological interest

ABOUT THIS SPECIMEN:

This listing includes a genuine double ammonite specimen—Kossmatia and Pseudotissotia—from the Riassin region in Russia, known for its exceptional fossil preservation. These fossils have been professionally prepared and preserved, allowing fine morphological details to be clearly seen. The fossil is pictured exactly as you will receive it, with no substitutes or replicas.

This piece is part of the Alice Purnell Collection, a well-known collection built over decades and trusted for its integrity, documentation, and exceptional curation.

WHAT YOU RECEIVE:

• Genuine paired fossil ammonites (Kossmatia & Pseudotissotia)
• Geological context: Barremian, Cretaceous, Riassin, Russia
• Professionally documented provenance
• Certificate of Authenticity included
• Safe and tracked packaging with detailed condition verification

SUMMARY:

This is a very rare and highly desirable ammonite fossil pairing of Kossmatia and Pseudotissotia from the Barremian of Russia, with excellent preservation and provenance from the renowned Alice Purnell Collection. A unique acquisition for fossil collectors, palaeontology enthusiasts, or museums seeking rare Cretaceous ammonites.