Amaltheus Gibbosus Ammonite Fossil Jurassic Somerset UK COA Upper Lias Radstock Toarcian Lower Jurassic

Description

Genuine Amaltheus gibbosus Ammonite Fossil from Radstock, Somerset

This is a genuine Amaltheus gibbosus ammonite fossil from the Upper Lias, dated to the Lower Jurassic, and recorded from Radstock, Somerset, UK. This carefully chosen fossil represents one of the classic ammonite forms associated with the British Jurassic marine succession, making it a desirable specimen for fossil collectors, geology enthusiasts, educational collections, and natural history displays.

The fossil shown in the photo is the actual specimen you will receive. Full sizing can be seen in the photo. This fossil also includes a Certificate of Authenticity lifetime guarantee generic card, giving confidence that the specimen is a genuine fossil and a carefully selected piece for collection or display.

Fossil Type and Species

Amaltheus gibbosus is an ammonite, an extinct marine cephalopod related to modern squid, cuttlefish, and nautilus. Ammonites lived inside coiled, chambered shells, using the outer chamber for the animal’s body while the internal chambers helped with buoyancy control. Their beautifully ribbed and coiled shells have made them one of the most recognisable and collectable fossil groups in the world.

The genus Amaltheus is known for its distinctive Jurassic ammonite form, often showing a compressed shell shape, strong ribbing, and a pronounced keel running around the outer edge of the whorl. These features are highly valued by collectors because they give the fossil a classic ammonite appearance while also preserving important details of shell growth and morphology. The name gibbosus reflects a more swollen or rounded form, making this a particularly interesting species within the group.

Geology and Age

This ammonite is from the Upper Lias, part of the Lower Jurassic marine rock sequence of Britain. The specimen is dated to the Toarcian Stage of the Lower Jurassic, a time when much of what is now southern and western Britain was covered by warm, shallow to moderately deep epicontinental seas. These Jurassic seas supported a rich marine ecosystem, including ammonites, belemnites, bivalves, marine reptiles, fish, and other invertebrates.

The Toarcian is especially important in palaeontology because ammonites evolved rapidly during this stage, making them excellent index fossils. Their changing shell forms allow geologists to compare and date rock layers across different regions. Ammonites such as Amaltheus are therefore not only attractive fossils but also scientifically important markers of Jurassic time.

Radstock, Somerset Fossil Location

Radstock in Somerset is historically well known for its geology and fossil-bearing Jurassic strata. The area forms part of the wider Somerset and South West England geological succession, where Lower Jurassic marine rocks preserve evidence of ancient seas that once covered the region. Fossils from Radstock are valued because they come from a classic British fossil locality with a strong historical connection to geology, palaeontology, and natural history collecting.

During the Lower Jurassic, the sediments that now form the Upper Lias were laid down in marine conditions. Fine muds, silts, and calcareous sediments accumulated on the sea floor, sometimes preserving the shells of ammonites after death. Over millions of years, these remains became buried, mineralised, and compressed into the fossil specimens collected today.

Ammonite Morphology and Display Features

This Amaltheus gibbosus fossil displays the classic coiled ammonite form that makes Jurassic ammonites so popular with collectors. The spiral shell records the growth of the animal, with each whorl representing a later stage of development. Ribbing on the shell surface would have strengthened the shell and may also have influenced hydrodynamics as the ammonite moved through the water.

The keel along the outer edge is one of the notable traits associated with Amaltheus ammonites. This feature gives the fossil a sharp, elegant profile and helps distinguish it from many smoother or more rounded ammonite forms. Natural preservation, matrix, mineral colour, surface texture, and any visible wear are all part of the fossil’s authentic geological character.

Certificate of Authenticity Included

This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card. It has been selected as an individual fossil piece, with the photograph showing the actual specimen supplied. This makes it suitable for collectors looking for a real British Jurassic ammonite, as well as for educational use, display cabinets, geology teaching sets, or as a thoughtful gift for anyone interested in fossils, natural history, and prehistoric marine life.