Leioceras and Catulloceras Ammonite Fossil Upper Aalenian Gloucestershire Sample | Birdlip UK Genuine Jurassic Specimen

Description

Genuine Leioceras and Catulloceras Ammonite Fossil

This carefully selected specimen contains ammonite material identified as Leioceras opalinum and Catulloceras sp. from Birdlip in Gloucestershire, UK. It is recorded from the Upper Aalenian stage of the Middle Jurassic. The photographs show the actual fossil you will receive, allowing its natural form, preservation, colour, matrix and visible details to be examined before purchase. Please refer to the photographs for full sizing and scale.

Aalenian Middle Jurassic Geology

The Aalenian Age lasted from approximately 174 to 170 million years ago and forms the opening stage of the Middle Jurassic. During this interval, much of southern and central Britain lay beneath warm marine waters. Mud, sand and carbonate-rich sediment accumulated on the seabed, preserving ammonites, belemnites, bivalves and other organisms.

Ammonites are exceptionally important for dating Jurassic marine strata. Their lineages evolved rapidly, individual species often had limited geological ranges and shells could be distributed across broad marine areas. Palaeontologists compare characteristic ammonite assemblages to recognise biozones and correlate rock layers between separate localities.

Leioceras opalinum

Leioceras is an extinct ammonite genus within the order Ammonitida. Leioceras opalinum is closely associated with the earliest Aalenian and gives its name to the Opalinum Zone, an important biostratigraphic interval around the beginning of the Middle Jurassic. Identification considers the degree of coiling, whorl proportions, umbilical width, shell ornament and the form of the outer margin.

Catulloceras sp.

Catulloceras is another extinct ammonite genus recorded from Jurassic marine deposits. The abbreviation sp. means that the fossil can be assigned to the genus while no specific species name is asserted. This standard scientific convention retains useful taxonomic information without overstating what can be determined from the preservation available.

Ammonites were marine cephalopods related to living squid, octopus and nautilus. Their coiled shells were internally divided into chambers. The animal occupied the final body chamber, while sealed earlier chambers helped regulate buoyancy. The presence of two identified ammonite forms adds interest by representing part of a wider marine fauna rather than an isolated geological label.

Natural Preservation

Fossil preservation varies naturally. The specimen may retain original shell material, mineral replacement, external impressions or internal moulds formed when sediment entered the shells. Matrix, worn surfaces, fractures and irregular edges reflect burial, compaction and later exposure. These authentic geological features are part of the fossil rather than manufactured defects.

Birdlip, Gloucestershire

Birdlip lies on the edge of the Cotswolds, an area famous for Jurassic limestones and associated fossil-bearing strata. Elevated ground overlooks the Severn Vale, while local quarries, cuttings and natural exposures reveal a long record of Jurassic marine sedimentation. Ammonites from Birdlip help geologists compare the Gloucestershire succession with equivalent rocks elsewhere in Britain and Europe.

The fossil represents cephalopods that lived in a sea covering the region more than 170 million years ago. Burial on the seabed protected their remains long enough for fossilisation, while later uplift and erosion exposed the rock within the modern Cotswold landscape.

Actual Specimen and Authenticity

You will receive the exact fossil shown in the photographs. Its dual ammonite identification, Upper Aalenian age and Birdlip provenance make it suitable for a specialist collection, geological study, educational display or a distinctive British fossil gift. It includes a generic Certificate of Authenticity card carrying a lifetime guarantee of authenticity.

Handle the specimen carefully and avoid soaking, harsh cleaning chemicals, excessive humidity and sudden temperature changes. Display it securely so natural edges, matrix and exposed fossil details remain protected.