Calycoceras subgentoni Ammonite Fossil Cenomanian Cretaceous UK Authentic Specimen COA

Description

Calycoceras subgentoni Ammonite Fossil

This listing features a fine Calycoceras subgentoni Ammonite Fossil from the Cenomanian stage of the Late Cretaceous, collected at Whitelands, Devon, United Kingdom. Dating to approximately 95–100 million years ago, this ammonite represents one of the key species used in stratigraphic studies of the early Late Cretaceous. The specimen pictured is the exact fossil you will receive, with a 1 cm scale cube for reference. All fossils are 100% genuine and supplied with a Certificate of Authenticity.

Geological Context – Cenomanian of Devon

This ammonite originates from the Lower Cenomanian deposits of Whitelands in Devon, a locality well-known for its rich chalk and marl sequences that preserve a wide range of marine life. The Cenomanian stage marks the beginning of the Late Cretaceous, a time when global sea levels were exceptionally high, submerging large parts of Europe beneath a warm, shallow sea. These marine conditions created ideal habitats for ammonites, inoceramid bivalves, echinoids, and a diverse assemblage of planktonic organisms.

The chalk and marl deposits of Devon are particularly valuable to geologists and paleontologists, as they contain well-preserved ammonites that provide precise age control for these rock sequences. The Calycoceras genus, including Calycoceras subgentoni, plays an essential role in defining ammonite biozones for the Cenomanian.

Species Overview – Calycoceras subgentoni

This specimen is identified as Calycoceras subgentoni, a species within the order Ammonitida, superfamily Acanthoceratoidea, and family Acanthoceratidae. Ammonites of this genus are characterised by their moderately involute shells with prominent ribbing and distinct tubercles along the ventrolateral margins.

Calycoceras subgentoni displays strong, regular ribs that may bifurcate across the flanks, creating a bold and diagnostic ornamentation. These features not only make the species easily recognisable but also reflect its adaptation to nektonic life in the open seas. The shell’s ribbing and tuberculation likely provided reinforcement and may have played a role in hydrodynamics or defence against predators.

Paleontological Importance

Calycoceras subgentoni is a highly significant index fossil for the Lower Cenomanian. Its restricted stratigraphic range and distinctive morphology make it invaluable for establishing ammonite biozones, which geologists use to date and correlate chalk and marl sequences across Europe and beyond.

The species also represents an important evolutionary development within the Acanthoceratidae, a family that reached its peak diversity during the Cretaceous. Its striking ribbing and tuberculation illustrate the evolutionary innovations of ammonites in response to ecological pressures during the Cenomanian.

Collector’s and Educational Value

This Calycoceras subgentoni ammonite fossil is a superb specimen for collectors of British and European ammonites. Its provenance from Whitelands, Devon, adds to its desirability, as fossils from this locality are both scientifically valuable and historically significant in Cretaceous research. With its bold ribbing and elegant shell structure, this specimen is equally suitable for display, study, or educational use.

Guarantee of Authenticity

• 100% genuine Calycoceras subgentoni ammonite fossil
• Supplied with a Certificate of Authenticity
• The exact specimen shown in the photographs will be sent

This is a rare opportunity to own a scientifically important and beautifully preserved Calycoceras subgentoni Ammonite Fossil from the Cenomanian of Whitelands, Devon, United Kingdom, an outstanding piece of Britain’s Cretaceous fossil record.