Asteroceras obtusum Ammonite Fossil Jurassic UK Authentic Specimen with Certificate COA
£ 36.00
ASTEROCERAS OBTUSUM AMMONITE FOSSILThis listing presents a fine Asteroceras obtusum Ammonite Fossil, discovered in
the Lower Lias, Lower Jurassic, from the Frodingham Ironstone Formation at Conesby Quarry, Scunthorpe, North Lincolnshire, United Kingdom. This fossil dates to the Obtusum Zone and Jamesoni Zone, approximately 196–190 million years old. The exact specimen shown in the photographs is the one you will receive, with a 1 cm scale cube provided for accurate size reference. Every fossil is 100% genuine and comes with a Certificate of Authenticity. GEOLOGICAL CONTEXT – THE FRODINGHAM IRONSTONE FORMATIONThe Conesby Quarry in North Lincolnshire is a classic site for Jurassic paleontology in Britain. The Frodingham Ironstone Formation is a well-known Lower Jurassic deposit, rich in ammonites, belemnites, brachiopods, and marine reptiles. Deposited in shallow seas, these ironstone beds represent an ancient marine ecosystem along the margins of the European epicontinental seas.The Obtusum Zone and Jamesoni Zone are highly significant for Jurassic stratigraphy, as ammonites from these intervals are used to define and correlate early Sinemurian stages across Europe. Fossils from Conesby Quarry are therefore scientifically valuable, serving as biostratigraphic markers as well as collectors’ pieces. SPECIES OVERVIEW – ASTEROCERAS OBTUSUMThis ammonite belongs to the genus Asteroceras, order Ammonitida, superfamily Eoderoceratoidea, and family Arietitidae. Asteroceras obtusum is one of the most distinctive ammonites of the Lower Lias.It is characterised by its moderately evolute shell with wide whorls and strong radial ribbing that runs cleanly across the flanks and ventral region. The ribs often give the ammonite a radiating or “star-like” appearance, reflecting the genus name Asteroceras (“star horn”). This diagnostic ribbing pattern makes Asteroceras obtusum both scientifically important and visually striking. PALEONTOLOGICAL IMPORTANCEAsteroceras obtusum is a classic index fossil of the Obtusum Zone, making it critical for biostratigraphy. Because it has a restricted stratigraphic range, it is used by geologists to date and correlate Lower Jurassic strata.Its shell morphology reflects evolutionary adaptations within the Arietitidae family. The robust ribs likely provided structural reinforcement against water pressure and predation, while also playing a role in buoyancy and hydrodynamics. These features highlight how ammonites adapted successfully to their marine environments during the Early Jurassic. COLLECTOR’S AND EDUCATIONAL VALUEThis Asteroceras obtusum ammonite fossil is highly desirable for collectors of British ammonites and Lower Jurassic fossils. Its provenance from Conesby Quarry, Scunthorpe, adds further scientific and historical importance, as this locality has long been a key source for ammonites used in defining biozones.For education, this ammonite is an outstanding example of ammonite morphology and biostratigraphic use. Its clear ribbing and shell structure demonstrate ammonite anatomy perfectly, making it a valuable specimen for teaching paleontology and Earth sciences. GUARANTEE OF AUTHENTICITY
• 100% genuine Asteroceras obtusum ammonite fossil
• Supplied with a Certificate of Authenticity
• The exact specimen photographed is the one you will receiveThis is a rare opportunity to acquire a scientifically significant and visually striking Asteroceras obtusum Ammonite Fossil from the Obtusum Zone of the Lower Jurassic, Conesby Quarry, Scunthorpe, United Kingdom—a superb addition to any serious fossil collection.
the Lower Lias, Lower Jurassic, from the Frodingham Ironstone Formation at Conesby Quarry, Scunthorpe, North Lincolnshire, United Kingdom. This fossil dates to the Obtusum Zone and Jamesoni Zone, approximately 196–190 million years old. The exact specimen shown in the photographs is the one you will receive, with a 1 cm scale cube provided for accurate size reference. Every fossil is 100% genuine and comes with a Certificate of Authenticity. GEOLOGICAL CONTEXT – THE FRODINGHAM IRONSTONE FORMATIONThe Conesby Quarry in North Lincolnshire is a classic site for Jurassic paleontology in Britain. The Frodingham Ironstone Formation is a well-known Lower Jurassic deposit, rich in ammonites, belemnites, brachiopods, and marine reptiles. Deposited in shallow seas, these ironstone beds represent an ancient marine ecosystem along the margins of the European epicontinental seas.The Obtusum Zone and Jamesoni Zone are highly significant for Jurassic stratigraphy, as ammonites from these intervals are used to define and correlate early Sinemurian stages across Europe. Fossils from Conesby Quarry are therefore scientifically valuable, serving as biostratigraphic markers as well as collectors’ pieces. SPECIES OVERVIEW – ASTEROCERAS OBTUSUMThis ammonite belongs to the genus Asteroceras, order Ammonitida, superfamily Eoderoceratoidea, and family Arietitidae. Asteroceras obtusum is one of the most distinctive ammonites of the Lower Lias.It is characterised by its moderately evolute shell with wide whorls and strong radial ribbing that runs cleanly across the flanks and ventral region. The ribs often give the ammonite a radiating or “star-like” appearance, reflecting the genus name Asteroceras (“star horn”). This diagnostic ribbing pattern makes Asteroceras obtusum both scientifically important and visually striking. PALEONTOLOGICAL IMPORTANCEAsteroceras obtusum is a classic index fossil of the Obtusum Zone, making it critical for biostratigraphy. Because it has a restricted stratigraphic range, it is used by geologists to date and correlate Lower Jurassic strata.Its shell morphology reflects evolutionary adaptations within the Arietitidae family. The robust ribs likely provided structural reinforcement against water pressure and predation, while also playing a role in buoyancy and hydrodynamics. These features highlight how ammonites adapted successfully to their marine environments during the Early Jurassic. COLLECTOR’S AND EDUCATIONAL VALUEThis Asteroceras obtusum ammonite fossil is highly desirable for collectors of British ammonites and Lower Jurassic fossils. Its provenance from Conesby Quarry, Scunthorpe, adds further scientific and historical importance, as this locality has long been a key source for ammonites used in defining biozones.For education, this ammonite is an outstanding example of ammonite morphology and biostratigraphic use. Its clear ribbing and shell structure demonstrate ammonite anatomy perfectly, making it a valuable specimen for teaching paleontology and Earth sciences. GUARANTEE OF AUTHENTICITY
• 100% genuine Asteroceras obtusum ammonite fossil
• Supplied with a Certificate of Authenticity
• The exact specimen photographed is the one you will receiveThis is a rare opportunity to acquire a scientifically significant and visually striking Asteroceras obtusum Ammonite Fossil from the Obtusum Zone of the Lower Jurassic, Conesby Quarry, Scunthorpe, United Kingdom—a superb addition to any serious fossil collection.
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