Rare Hybodus Fin Spine Fossil Jurassic Lyme Regis Dorset UK Lower Lias Shark Specimen

Description

Rare Hybodus Fin Spine Fossil from the Jurassic Coast

This authentic Hybodus fin spine fossil originates from the Black Ven Marls of the Lower Lias Formation at Stonebarrow Cliff near Charmouth, Lyme Regis, Dorset, United Kingdom. Lyme Regis lies along the world-famous Jurassic Coast UNESCO World Heritage Site, one of the most important fossil-bearing coastlines in the world and renowned for its exceptional Early Jurassic marine fossils.

The specimen represents a dorsal fin spine from a Hybodus shark, an extinct genus of hybodont sharks that lived from the Late Paleozoic through the Mesozoic Era. Fossils from this genus are an important component of Early Jurassic marine ecosystems. Hybodus sharks were among the dominant cartilaginous fish inhabiting the shallow seas that covered southern England approximately 196 to 190 million years ago during the Sinemurian Stage of the Early Jurassic.

This fossil has been carefully selected for preservation and display quality, showing the elongated form and characteristic surface texture typical of hybodont fin spines. The photographs in the listing show the exact fossil specimen you will receive, and full sizing can be viewed in the listing images.

This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card, confirming its authenticity and geological origin.

Scientific Classification of Hybodus Sharks

Hybodus belonged to a now-extinct group of sharks known as hybodontiforms, which were widespread throughout Mesozoic marine environments.

Scientific classification includes:

• Kingdom: Animalia
• Phylum: Chordata
• Class: Chondrichthyes
• Subclass: Elasmobranchii
• Order: Hybodontiformes
• Family: Hybodontidae
• Genus: Hybodus

Hybodont sharks represent an ancient lineage of cartilaginous fish that differed from modern sharks in several anatomical features, including distinctive dorsal fin spines and unique tooth morphology adapted for a varied diet.

Morphology of Hybodus Fin Spines

One of the most recognisable features of hybodont sharks is their large dorsal fin spines, which projected from the front of their dorsal fins. These spines served both structural and defensive functions.

Typical characteristics of Hybodus fin spines include:

• Long, tapered spine shape
• Strong central ridge along the length of the spine
• Surface ornamentation with longitudinal ridges
• Hard mineralised outer layer
• Solid internal structure for support

These spines were composed of dentine and enamel-like tissues, making them more resistant to decay than the cartilaginous skeleton of the shark itself. As a result, fin spines are among the most commonly preserved skeletal remains of hybodont sharks.

Geological Formation and Stratigraphy

This specimen originates from the Black Ven Marls, part of the Lower Lias Formation, which was deposited during the Early Jurassic.

Key geological details include:

• Formation: Black Ven Marls
• Stratigraphic Group: Lower Lias
• Geological Period: Jurassic
• Stage: Sinemurian
• Approximate Age: 196–190 million years

The Black Ven Marls consist mainly of:

• Dark grey marine marl
• Clay-rich shale
• Thin limestone bands
• Fossil-rich sediment layers

These sediments were deposited in a calm marine basin where fine mud accumulated on the seabed, preserving a diverse range of marine organisms.

Early Jurassic Marine Ecosystem of Dorset

During the Early Jurassic Period, southern England lay beneath a warm shallow sea connected to the Tethys Ocean. This marine environment supported a rich ecosystem of marine life.

Animals inhabiting these waters included:

• Sharks such as Hybodus
• Marine reptiles including ichthyosaurs and plesiosaurs
• Ammonites and belemnites
• Bony fish
• Bivalves and brachiopods

Predatory sharks such as Hybodus played an important role within this ecosystem, feeding on fish, cephalopods, and other marine organisms.

Fossilisation of Hybodont Shark Remains

Unlike modern sharks, whose skeletons are composed largely of cartilage, hybodont sharks possessed mineralised fin spines that fossilised more readily than the rest of their skeleton.

When these sharks died, their skeletal elements could settle onto the seabed and become buried within sediment. Over millions of years, mineralisation replaced the original biological material, preserving the structure of the fin spine within the rock.

Because of their durable composition, fin spines often survive fossilisation when other skeletal elements do not.

Fossil Discoveries at Stonebarrow Cliff

Stonebarrow Cliff near Charmouth is one of the most productive fossil localities along the Dorset coast. The cliffs expose layers of Lower Lias sediment that continue to yield fossils through natural erosion.

The region has played a crucial role in the history of palaeontology, with numerous discoveries contributing to our understanding of Early Jurassic marine ecosystems.

Fossils from the Jurassic Coast are highly regarded by collectors due to their scientific significance and preservation quality.

Authentic Fossil Specimen

This specimen represents a genuine Hybodus shark fin spine fossil from the Black Ven Marls of the Lower Lias Formation at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, United Kingdom.

Key details include:

• Authentic Hybodus shark fin spine fossil
• Rare hybodont shark skeletal element
• Geological Formation: Black Ven Marls
• Stratigraphy: Lower Lias Formation
• Geological Age: Early Jurassic
• Stage: Sinemurian
• Locality: Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Fossil from the Jurassic Coast UNESCO World Heritage Site
• Exact specimen shown in listing photographs
• Full sizing visible in listing images
• Includes Certificate of Authenticity lifetime guarantee generic card

This fossil represents a preserved anatomical feature of a Jurassic shark that once inhabited the ancient seas of southern Britain, making it an exceptional addition to fossil collections, geological displays, and natural history exhibits.