Eparietites denotatus Ammonite Fossil Scunthorpe Mudstone Jurassic Lincolnshire UK Lower Jurassic Sinemurian Marine Cephalopod

Description

Genuine Eparietites denotatus Ammonite Fossil from the Lower Jurassic

This authentic fossil ammonite, identified as Eparietites denotatus, originates from the Scunthorpe Mudstone Formation of Scunthorpe, Lincolnshire, UK. Dating to the Lower Jurassic period during the Sinemurian stage, approximately 199–190 million years ago, this fossil represents a classic example of early Jurassic marine cephalopod life preserved within the sedimentary deposits of northern England.

The specimen shown in the photographs is the exact fossil you will receive. It has been carefully selected as a quality example of this distinctive ammonite species and comes with a Certificate of Authenticity lifetime guarantee generic card confirming that the fossil is a genuine natural specimen. Please refer to the photographs for full sizing and proportions.

Species Overview – Eparietites denotatus

Eparietites denotatus is a well-known Lower Jurassic ammonite belonging to the order Ammonitida, a group of extinct marine cephalopods closely related to modern squids, octopuses, and cuttlefish. Ammonites possessed coiled shells divided internally into chambers that regulated buoyancy, allowing them to move efficiently through the water column.

The genus Eparietites is characteristic of the Sinemurian stage and is frequently used by palaeontologists as an index fossil to identify and correlate specific layers of Lower Jurassic marine sediment. The species is associated with the Arietitidae family within the superfamily Psiloceratoidea, a group known for their robust shells and prominent ribbing patterns.

These ammonites lived in warm, shallow seas that once covered much of what is now Britain, forming part of a thriving marine ecosystem rich in fish, crustaceans, and marine reptiles.

Morphology and Shell Characteristics

Ammonites such as Eparietites denotatus are recognised for their distinctive coiled shell morphology and ribbed ornamentation. The shell typically displays strong radial ribbing that radiates outward from the inner whorls toward the outer shell margin. These ribs often cross the venter, creating a textured appearance that is both scientifically distinctive and visually striking.

The shell is composed primarily of aragonite in life, although fossil specimens have typically undergone mineral replacement during diagenesis, preserving the shell in limestone or mudstone matrices. Internally, the ammonite shell consisted of a series of gas-filled chambers separated by septa, connected by a tube known as the siphuncle which regulated buoyancy.

The coiled structure allowed the animal to maintain stability and control its vertical position within the Jurassic sea.

Geological Context – Scunthorpe Mudstone Formation

The Scunthorpe Mudstone Formation is an important Lower Jurassic geological unit found across parts of northern England. It consists primarily of marine mudstones and shales deposited in a shallow epicontinental sea during the Sinemurian stage.

These sediments accumulated on the seafloor under relatively calm marine conditions, allowing fine mud particles to settle and bury the remains of marine organisms. Over millions of years, pressure and mineralisation transformed these sediments into rock while preserving fossils such as ammonites, bivalves, and marine reptiles.

Ammonites from this formation are particularly significant to palaeontology because they help define detailed biostratigraphic zones within the Early Jurassic. The presence of species like Eparietites denotatus provides valuable markers used by geologists to identify specific layers within the Sinemurian succession.

The Jurassic Marine Environment

During the Early Jurassic, the region that is now Lincolnshire was submerged beneath a warm shallow sea connected to the larger Tethyan ocean system. These waters supported a diverse marine ecosystem populated by ammonites, belemnites, fish, crustaceans, and marine reptiles such as ichthyosaurs.

Ammonites occupied a crucial role in this ecosystem as both predators and prey. They likely fed on small marine organisms including plankton, crustaceans, and larvae, while themselves being hunted by larger predators.

Their rapid evolutionary rates and widespread distribution make ammonites among the most important fossils for understanding the geological timeline of the Mesozoic Era.

Authenticity and Collectability

• Genuine fossil ammonite identified as Eparietites denotatus

• Scunthorpe Mudstone Formation, Lower Jurassic

• Sinemurian stage, approximately 199–190 million years old

• Collected from Scunthorpe, Lincolnshire, United Kingdom

• The fossil shown in the photographs is the exact specimen you will receive

• Includes a Certificate of Authenticity lifetime guarantee generic card

Ammonites from the Sinemurian stage are highly sought after by collectors due to their geological significance and classic Jurassic preservation. This Eparietites denotatus specimen represents a beautiful and scientifically important fossil from the Early Jurassic seas of Britain, making it an excellent addition to any fossil collection, geological display, or natural history study.