RARE Psiloceras planorbis Fossil Ammonite | Hettangian Jurassic Whitby Yorkshire UK | Authentic Certified Specimen

Description This listing features a scientifically important and rare specimen of the ammonite Psiloceras planorbis, recovered from the Hettangian Stage of the Early Jurassic period, near Whitby, Yorkshire, United Kingdom. This fossil is a highly desirable collector’s piece, particularly valued for its historical and geological significance. The specimen you see in the photo is the actual fossil you will receive. All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. Geological and Taxonomic Information: Species: Psiloceras planorbis Described by: James Sowerby, 1817 Type: Fossil Ammonite (extinct marine cephalopod) Geological Period: Jurassic Stage: Lower Hettangian Biozone: Planorbis Zone Formation: Lower Lias Group (likely Blue Lias Formation) Depositional Environment: Offshore marine basin with low oxygen bottom waters, contributing to the exceptional preservation of fossils Location Found: Whitby, Yorkshire, United Kingdom Taxonomic Classification: Order: Ammonitida Superfamily: Psiloceratoidea Family: Psiloceratidae Morphological Features: Involute, smooth shell with a very narrow umbilicus Characteristic flat, discoidal shape Lacks ribbing or ornamentation, which gives the genus its name (“Psiloceras” means “smooth horn”) Sutures are relatively simple compared to later Jurassic ammonites Exhibits the earliest morphological features of post-Triassic ammonite lineages Scientific Importance: Psiloceras planorbis is an internationally recognised index fossil that marks the base of the Jurassic System. The first occurrence of this species defines the Planorbis Biozone, the lowest ammonite zone in the Jurassic. Its global distribution and position in the stratigraphic column make it essential for dating Lower Jurassic rocks across Europe and beyond. This fossil represents not only a beautiful specimen but also a key marker in Earth’s geological history, appearing shortly after the Triassic-Jurassic mass extinction event. Specimen Notes: Carefully chosen for preservation and scientific relevance Scale rule visible in photo – squares/cube = 1 cm You will receive the exact specimen shown in the listing photographs Authenticity & Guarantee: This is an authentic fossil specimen, legally sourced and professionally verified. A Certificate of Authenticity is included with every purchase, offering peace of mind and added value whether for a private collection, educational purpose, or display. Perfect For: Fossil collectors and paleontology enthusiasts Educational use and academic study Museums or natural history displays Unique gifts for geology lovers