Dactylioceras tenuicostatum Fossil Ammonite Whitby Jurassic Middle Lias

Description Dactylioceras tenuicostatum Fossil Ammonite – Middle Lias, Whitby UK Bring a true piece of Britain’s Jurassic coastline into your collection with this authentic Dactylioceras tenuicostatum fossil ammonite, sourced from the famous exposures of Runswick Bay, Whitby, North Yorkshire, United Kingdom. Dating to the Middle Lias (Early Jurassic), this classic ammonite species is one of the most recognisable and collectible marine fossils from the Yorkshire coast. This fossil is a carefully chosen specimen, and the photo shows the actual piece you will receive. Full sizing details can be found in the listing photographs. Every specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming it as a genuine fossil. Fossil Identification & Species Details Species: Dactylioceras tenuicostatum Fossil Type: Ammonite (extinct marine cephalopod) Order: Ammonitida Superfamily: Eoderoceratoidea Family: Dactylioceratidae Age: Early Jurassic Formation: Middle Lias deposits Locality: Runswick Bay, Whitby, Yorkshire Coast, UK Dactylioceras tenuicostatum is especially well known for its finely ribbed shell and elegant coiled form, making it a standout example of Jurassic ammonite morphology. Geological Age – The Middle Lias, Jurassic Seas This ammonite lived approximately 180 million years ago, during the Early Jurassic period when much of what is now the UK was covered by warm, shallow seas. The Middle Lias strata of the Whitby area are world-famous for preserving abundant marine life, including ammonites, belemnites, and other invertebrates. These fossil-rich deposits formed in offshore environments where fine muds accumulated on the sea floor, later solidifying into shale and limestone layers. The presence of Dactylioceras tenuicostatum is also significant in Jurassic stratigraphy, as it is associated with the well-known Tenuicostatum Zone, an important ammonite biozone used for dating Early Jurassic rocks. Morphology & Collectable Features This species is prized for its distinctive and highly detailed shell characteristics: Tightly coiled, planispiral form Fine, dense ribbing across the whorls Strong natural symmetry Classic Whitby preservation style Ammonites like this were active predators, related to modern squid and octopus, using their chambered shells for buoyancy control as they moved through Jurassic oceans. Authenticity, Sizing & Presentation Genuine fossil ammonite specimen Carefully selected collectible piece Actual fossil shown in the photo Includes Certificate of Authenticity lifetime guarantee generic card Sizing: Please refer to photographs for full measurements Natural fossils may show minor surface textures or preparation marks consistent with authentic preservation and careful cleaning. Perfect for Collectors, Display & Gifts A Whitby ammonite is a timeless addition to: Fossil and palaeontology collections Natural history displays Educational study pieces Unique Jurassic-themed gifts With its classic Yorkshire provenance and scientifically recognised species, this Dactylioceras tenuicostatum fossil ammonite is a superb example of Britain’s prehistoric marine heritage.