Description
Androgynoceras lateacosta Ammonite Fossil
This genuine Androgynoceras lateacosta fossil ammonite comes from the Scunthorpe Mudstone Formation of the Lower Jurassic, collected from Scunthorpe, Lincolnshire, UK. It is a classic British Jurassic ammonite specimen from the Sinemurian stage, representing an important period in the early evolution and diversification of ammonites within the ancient seas that once covered much of what is now Britain.
Androgynoceras is a distinctive ammonite genus from the Lower Jurassic and is especially valued by collectors for its strong ribbing, attractive coiled shell form and geological importance. Ammonites were extinct marine cephalopods related to modern squid, cuttlefish and nautilus. Their shells were divided into internal chambers, with the living animal occupying the final outer chamber. As they evolved rapidly through geological time, ammonites are highly important index fossils used for dating and correlating Jurassic rock layers.
Geological Location and Age
This fossil was found in the Scunthorpe Mudstone Formation, Lower Jurassic, Sinemurian stage, Scunthorpe, Lincolnshire, UK. The Scunthorpe Mudstone Formation forms part of the Lower Lias Group and is composed mainly of fossiliferous mudstones and limestones deposited in a shallow marine environment during the Early Jurassic.
The Sinemurian stage dates to approximately 199 to 191 million years ago. During this time, the region that is now Lincolnshire lay beneath a warm epicontinental sea. Fine marine sediments accumulated across the sea floor, preserving ammonites, bivalves, belemnites, crinoid remains and other marine fossils. Over millions of years, these sediments compacted into mudstone and limestone, creating the fossil-bearing horizons now known from the Scunthorpe area.
Species and Fossil Detail
Androgynoceras lateacosta is a named ammonite species with a coiled, planispiral shell and ribbed ornamentation typical of many Lower Jurassic ammonites. The shell form would have helped the animal move through the water column, while its chambered internal structure allowed buoyancy control. The external ribbing is one of the most important visible features, giving the fossil its characteristic Jurassic ammonite appearance and helping distinguish it from related genera and species.
The species name lateacosta refers to the nature of the ribbing, with “costa” relating to ribs. In ammonite study, rib strength, spacing, whorl shape, umbilicus width and overall shell profile are all important features used in identification. These details make Androgynoceras lateacosta an interesting specimen for collectors of British ammonites, Lower Jurassic fossils and scientifically named display pieces.
Scientific Classification and Palaeontology
Androgynoceras belongs to the ammonite order Ammonitida and is associated with the superfamily Eoderoceratoidea. It is part of the broader Lower Jurassic ammonite faunas that are well known from Britain and Europe. These ammonites are particularly important in biostratigraphy because their rapid evolutionary changes allow geologists to divide the Jurassic rocks into detailed fossil zones and horizons.
The Scunthorpe Mudstone Formation is a significant British Lower Jurassic unit and has yielded a wide range of marine fossils. Ammonites such as Androgynoceras are among the most useful fossils from these beds, helping to interpret the age of the rocks and the ancient marine environments in which they formed.
Depositional Environment
The sediments of the Scunthorpe Mudstone Formation were laid down in a marine setting, where mud, carbonate-rich sediment and organic remains accumulated on the sea floor. The environment supported a diverse marine ecosystem including ammonites swimming in the water column, bivalves living on or within the sea bed, belemnites moving as active predators, and other invertebrates forming part of the Jurassic food web.
After death, ammonite shells could settle onto the sea floor and become buried in fine sediment. With the right conditions, the shell or internal mould was preserved as a fossil. This specimen represents one of those ancient marine remains, preserved for around 190 million years before being recovered from the Jurassic rocks of Lincolnshire.
Authenticity and Presentation
This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card. Full sizing please see photo. The fossil is a carefully chosen piece, with the photo showing the actual specimen you will receive.
This Androgynoceras lateacosta ammonite is ideal for fossil collectors, Jurassic ammonite specialists, British geology enthusiasts, educational collections and natural history displays. With its named species, Lower Jurassic age, Sinemurian geological setting and Scunthorpe Mudstone Formation provenance, it is a highly appealing specimen for anyone interested in classic British fossils from the early Jurassic seas.
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