Androgynoceras Ammonite Fossil Jurassic Charmouth Lyme Regis Dorset UK Specimen

Description

Androgynoceras Ammonite Fossil from Stonebarrow Cliff, Charmouth

This genuine fossil specimen is an Androgynoceras ammonite discovered within the famous Green Ammonite Beds of the Lower Lias Formation at Stonebarrow Cliff near Charmouth, Lyme Regis, Dorset, United Kingdom. These fossil-bearing deposits form part of the internationally recognised Jurassic Coast World Heritage Site, one of the most important geological regions in the world for Jurassic fossils.

Your specimen was discovered by our own team members, Alister and Alison, on 15 January 2026 along the Dorset coastline. After recovery, the fossil was carefully cleaned, prepared, and treated by Alison, ensuring that the shell structure and rib patterns were clearly visible while preserving the natural character of the specimen.

The photographs in the listing show the exact fossil specimen you will receive, making this a unique piece for collectors. The fossil is 100 percent genuine and includes a Certificate of Authenticity with a lifetime guarantee card confirming its authenticity.

Full sizing of the specimen can be seen in the listing photographs.

Geological Origin – Green Ammonite Beds, Lower Lias

This ammonite originates from the Green Ammonite Beds, a well-known fossil-bearing layer within the Lower Lias Group exposed along the cliffs between Charmouth and Lyme Regis in Dorset. These rocks were deposited during the Early Jurassic Period, approximately 190 million years ago, within the Sinemurian Stage.

The Lower Lias sediments consist primarily of marine limestones and mudstones, deposited in a shallow sea that covered much of southern Britain at the time. Fine sediment accumulated on the seabed where marine organisms lived and died, allowing their remains to become preserved as fossils.

The Green Ammonite Beds are particularly famous for their abundance of ammonites and are widely studied by palaeontologists. The layers contain a rich assemblage of marine fossils including:

• Ammonites
• Belemnites
• Bivalves and gastropods
• Marine reptiles such as ichthyosaurs
• Crinoids and other echinoderms

These deposits provide an important record of marine life in the early Jurassic seas.

Androgynoceras – Distinctive Early Jurassic Ammonite

The genus Androgynoceras belongs to the ammonite family Liparoceratidae, a group of large, strongly ornamented ammonites that flourished during the Early Jurassic.

Taxonomic classification:

• Phylum: Mollusca
• Class: Cephalopoda
• Subclass: Ammonoidea
• Order: Ammonitida
• Superfamily: Eoderoceratoidea
• Family: Liparoceratidae
• Genus: Androgynoceras

Ammonites of this genus are well known for their robust shell ornamentation and distinctive rib patterns, which make them particularly attractive fossils for collectors.

Morphology and Shell Structure

Like other ammonites, Androgynoceras possessed a coiled external shell divided internally into chambers. These chambers formed part of a buoyancy control system that allowed the animal to move vertically within the water column.

Characteristic features of Androgynoceras ammonites include:

• A planispiral coiled shell
• Strong radial ribbing across the shell surface
• An evolute shell form with visible inner whorls
• Pronounced rib patterns that sometimes form tubercles
• Complex ammonitic suture patterns between internal chambers

The ribbing strengthened the shell and is one of the key diagnostic features used to identify this genus. These ribs also create the striking texture that makes Androgynoceras fossils visually distinctive.

Early Jurassic Marine Environment of Dorset

During the Early Jurassic, the area that is now Dorset lay beneath a warm shallow sea connected to the wider Tethys Ocean. These waters supported a rich marine ecosystem populated by numerous invertebrates and marine reptiles.

The marine environment where Androgynoceras lived included:

• Ammonites and belemnites
• Marine reptiles such as ichthyosaurs and plesiosaurs
• Bivalves and gastropods
• Echinoderms including crinoids

Ammonites were active marine animals that used jet propulsion to move through the water, similar to modern squid. They likely preyed on small marine organisms including crustaceans and planktonic animals.

When ammonites died, their shells sank to the seabed where they were gradually buried by sediment and eventually fossilised within the limestone layers.

Authentic Jurassic Coast Fossil Discovered by Our Team

This fossil represents a genuine specimen collected directly from one of the most famous fossil localities in the world. Fossils discovered and prepared by experienced collectors from the Dorset coast are highly valued by enthusiasts and collectors.

Key features of this specimen include:

• Genuine Androgynoceras ammonite fossil
• From the Green Ammonite Beds of the Lower Lias
• Early Jurassic Period
• Collected at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Discovered by Alister and Alison on 15 January 2026
• Cleaned, prepared, and treated by Alison
• Photographs show the exact fossil specimen you will receive
• Supplied with a Certificate of Authenticity and lifetime guarantee

This impressive ammonite makes an excellent addition to Jurassic fossil collections, ammonite displays, geology collections, and natural history exhibits, offering a remarkable example of marine life from the ancient Jurassic seas of the Dorset coastline.