Polyptychites polyptychus Ammonite Fossil Hauterivian Cretaceous Speeton UK Genuine Certified

Description

Authentic Polyptychites polyptychus Ammonite Fossil from Speeton, United Kingdom

This genuine Polyptychites polyptychus ammonite fossil originates from the Speeton Clay Formation in Yorkshire, United Kingdom, dating to the Hauterivian stage of the Lower Cretaceous period (approximately 132–129 million years ago). A rare and scientifically significant ammonite, it represents an important fossil species used by palaeontologists to understand Early Cretaceous marine life. The specimen comes with a Certificate of Authenticity and is displayed with a 1 cm scale cube in the photos to provide accurate sizing. The piece shown is the exact fossil you will receive.

Geological Significance – Speeton Clay Formation

The Speeton Clay Formation is one of the most valuable fossil-bearing deposits in northern Europe, stretching along the Yorkshire coast. It preserves an exceptional record of the Early Cretaceous marine ecosystem within finely bedded clays and marls that formed under calm, deep-sea conditions. These anaerobic environments were perfect for fossil preservation, ensuring delicate details of ammonites, belemnites, bivalves, and other marine fauna remain intact. Ammonites such as Polyptychites polyptychus are crucial for establishing biostratigraphic zones that allow geologists to correlate marine strata across different regions of Europe.

Scientific Classification

• Class: Cephalopoda
• Subclass: Ammonoidea
• Order: Ammonitida
• Superfamily: Perisphinctoidea
• Family: Polyptychitidae
• Genus: Polyptychites
• Species: Polyptychites polyptychus

As a distinctive representative of the family Polyptychitidae, this ammonite species is a key index fossil for the Hauterivian stage, making it especially valuable for both collectors and scientific study.

Morphological Features

Polyptychites polyptychus is characterised by a moderately involute shell with ribbing that bifurcates across the flanks and often continues across the venter. These ribs create a strong ornamental structure, which not only distinguishes it from other ammonites but also provides insights into the hydrodynamics and evolutionary adaptations of the species. The shell morphology reflects both buoyancy control and streamlining, allowing the animal to navigate effectively through the Cretaceous seas. Its intricate ribbing and well-defined whorl structure make it a visually striking specimen.

Depositional Environment and Palaeontology

During the Hauterivian stage, the Speeton region was submerged under a warm epicontinental sea. The clays and marls of the formation accumulated slowly, preserving a snapshot of marine life in a relatively undisturbed setting. Ammonites such as Polyptychites polyptychus thrived as agile predators, preying on small crustaceans, molluscs, and planktonic organisms. Their abundance in the Speeton Clay demonstrates the richness of the Early Cretaceous seas, while their evolutionary diversity provides important data for understanding cephalopod development during this time.

Collector and Display Value

This specimen of Polyptychites polyptychus represents more than a striking fossil; it is a rare and scientifically significant ammonite that directly connects to the biostratigraphic framework of the Early Cretaceous. Its sharp ribbing and defined coiling patterns make it both aesthetically pleasing and academically important. Fossils from the Speeton Clay are prized among collectors for their provenance, and Polyptychites polyptychus is especially sought after due to its role as a zonal fossil.

Whether you are a seasoned palaeontologist, an enthusiastic collector, or someone seeking a unique natural history display piece, this ammonite offers both beauty and scientific importance. It is a 100% genuine fossil, carefully chosen and authenticated, representing a fascinating chapter in Earth’s evolutionary history.