Fossils for Sale - High-quality BRITISH and WORLDWIDE Fossils. An impressive selection of fossils, including Ammonites, Trilobites, Belemnites, Fossil Fish, Fossil Shark Teeth, Fossilised Insects in Amber, Dinosaurs, and Reptiles. UK Fossils was formed in 1988 and collects and preps our own fossils in the heart of the Jurassic Coast, collecting fossils from Lyme Regis, Charmouth and Somerset. Our passion for fossils is reflected in our carefully curated collection, which includes some of the rarest and most unique specimens available.

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RARE 10″ Pseudasteroceras stellaformis Fossil Ammonite | Sinemurian Jurassic | Robin Hood’s Bay Yorkshire UK | Certified Authentic Specimen

£240.00

An extraordinary and rare 10-inch fossil ammonite: Pseudasteroceras stellaformis from the Sinemurian Stage of the Early Jurassic, collected from the iconic coastal exposures at Robin Hood’s Bay, Yorkshire Coast, United Kingdom. This beautifully preserved and large specimen showcases the stunning ribbed architecture typical of this genus and represents a key faunal element in Lower Jurassic stratigraphy.

This listing features the exact specimen shown in the photographs. A 1cm scale cube is included for accurate size reference—please see the images for full detail and dimensions.

 

Geological & Palaeontological Information:

  • Fossil Type: Ammonite
  • Species: Pseudasteroceras stellaformis (first described by Fucini, later associated with early Sinemurian faunas)
  • Geological Period: Jurassic
  • Stage: Sinemurian (~199 to 190 million years ago)
  • Location: Robin Hood’s Bay, Yorkshire Coast, England, UK
  • Depositional Environment: Marine shelf with alternating mudstones and shales from the Lower Lias Formation
  • Order: Ammonitida
  • Superfamily: Eoderoceratoidea
  • Family: Arietitidae
  • Biozone (Inferred): Possibly within the Bucklandi or Obtusum Zone of the Lower Sinemurian, common in Robin Hood’s Bay stratigraphy

 

Morphological Features:

  • Large evolute shell with strongly ribbed, ornamented flanks
  • Deep umbilicus and pronounced, bifurcating ribs
  • Slightly keeled venter or smooth ventral band
  • Dramatic spiral structure ideal for display and stratigraphic reference

 

Notable Points:

  • Pseudasteroceras stellaformis is a rare species, particularly in large, complete form
  • Robin Hood’s Bay is one of the most significant Lower Jurassic fossil sites in the world
  • Specimens from this site are important for understanding ammonite evolution and regional biostratigraphy

 

Why This Fossil is Exceptional:

  • Rare large ammonite from a scientifically important locality
  • Excellent preservation, size, and aesthetic display value
  • Ethically sourced and supplied with a Certificate of Authenticity
  • Perfect for collectors, educators, museums, or natural history displays

 

(Actual as seen)

Out of stock

SKU: UF4497 Category:

Description

An extraordinary and rare 10-inch fossil ammonite: Pseudasteroceras stellaformis from the Sinemurian Stage of the Early Jurassic, collected from the iconic coastal exposures at Robin Hood’s Bay, Yorkshire Coast, United Kingdom. This beautifully preserved and large specimen showcases the stunning ribbed architecture typical of this genus and represents a key faunal element in Lower Jurassic stratigraphy.

This listing features the exact specimen shown in the photographs. A 1cm scale cube is included for accurate size reference—please see the images for full detail and dimensions.

 

Geological & Palaeontological Information:

  • Fossil Type: Ammonite
  • Species: Pseudasteroceras stellaformis (first described by Fucini, later associated with early Sinemurian faunas)
  • Geological Period: Jurassic
  • Stage: Sinemurian (~199 to 190 million years ago)
  • Location: Robin Hood’s Bay, Yorkshire Coast, England, UK
  • Depositional Environment: Marine shelf with alternating mudstones and shales from the Lower Lias Formation
  • Order: Ammonitida
  • Superfamily: Eoderoceratoidea
  • Family: Arietitidae
  • Biozone (Inferred): Possibly within the Bucklandi or Obtusum Zone of the Lower Sinemurian, common in Robin Hood’s Bay stratigraphy

 

Morphological Features:

  • Large evolute shell with strongly ribbed, ornamented flanks
  • Deep umbilicus and pronounced, bifurcating ribs
  • Slightly keeled venter or smooth ventral band
  • Dramatic spiral structure ideal for display and stratigraphic reference

 

Notable Points:

  • Pseudasteroceras stellaformis is a rare species, particularly in large, complete form
  • Robin Hood’s Bay is one of the most significant Lower Jurassic fossil sites in the world
  • Specimens from this site are important for understanding ammonite evolution and regional biostratigraphy

 

Why This Fossil is Exceptional:

  • Rare large ammonite from a scientifically important locality
  • Excellent preservation, size, and aesthetic display value
  • Ethically sourced and supplied with a Certificate of Authenticity
  • Perfect for collectors, educators, museums, or natural history displays

 

Additional information

Era

Jurassic

Origin

United Kingdom

Jurassic Information

The Jurassic Period (201–145 million years ago) was the golden age of dinosaurs, with iconic species like Brachiosaurus, Stegosaurus, and Allosaurus dominating the land. It was a time of warm, humid climates, with high sea levels that created vast shallow seas, supporting abundant marine reptiles, ammonites, and early coral reefs. The first birds, such as Archaeopteryx, evolved from small theropod dinosaurs, while early mammals remained small and nocturnal. Lush forests of cycads, conifers, and ferns covered the land, providing food for giant herbivores. The breakup of the supercontinent Pangaea accelerated, shaping Earth's geography and setting the stage for the diverse ecosystems of the Cretaceous.

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