Dactylioceras tenuicostatum Ammonite Fossil Jurassic Whitby UK Genuine Specimen Certificate

Description

Genuine Jurassic Ammonite Fossil – Dactylioceras tenuicostatum

This listing is for a Dactylioceras tenuicostatum Fossil Ammonite, collected from the famous fossil-rich coast of Runswick Bay, Whitby, United Kingdom. This striking specimen originates from the Middle Lias (Lower Jurassic), approximately 180 million years old, and provides both a scientifically valuable and aesthetically pleasing example of this classic Whitby ammonite. It has been carefully selected for quality and authenticity, with photographs showing the exact fossil you will receive.

Geological Age and Locality

The ammonite comes from the Jurassic Period, specifically the Middle Lias, Lower Jurassic, within the Upper Pliensbachian stage. The Whitby coastline, particularly Runswick Bay, is renowned worldwide for producing ammonites of exceptional preservation. The fossil-bearing strata here represent shallow marine deposits, where fine sediments rapidly buried organisms, creating ideal conditions for fossilisation. These ammonite-rich deposits have been studied extensively since the 19th century and remain a cornerstone of Jurassic paleontology.

Fossil Type and Species

This specimen represents Dactylioceras tenuicostatum, a species belonging to the family Dactylioceratidae, superfamily Eoderoceratoidea, and order Ammonitida. Ammonites were extinct marine molluscs related to squids and octopuses. Their spiral shells served both as buoyancy devices and protection. Dactylioceras tenuicostatum is distinguished by its slender ribbing and has long been recognised as an important index fossil, used to define the internationally significant Tenuicostatum Zone of the Pliensbachian. This makes it not only a collectible specimen but also a fossil of high stratigraphic importance.

Morphology and Distinctive Features

Key features of Dactylioceras tenuicostatum include:

• Slender, closely spaced ribs that give the species its name (“tenuicostatum” meaning finely ribbed).
• A planispiral shell with tight coiling and relatively narrow whorls.
• A moderate umbilicus, exposing inner coils clearly.
• Well-defined suture lines dividing the internal chambers.

These features are clearly preserved in many Whitby specimens, and they highlight the precision with which paleontologists can distinguish different ammonite species. The delicate ribbing pattern of D. tenuicostatum makes it particularly attractive for collectors and an invaluable fossil for identifying specific Jurassic time intervals.

Biozone and Scientific Importance

The Tenuicostatum Zone, named after Dactylioceras tenuicostatum, is a critical biozone in the Jurassic time scale. Ammonites of this species are widely distributed across Europe and have been used for decades as reliable stratigraphic markers. Collectors owning such a specimen hold not only a fossil of visual beauty but also one with deep scientific importance in dating and correlating ancient rock formations.

Depositional Environment

During the Early Jurassic, Whitby was submerged beneath a shallow epicontinental sea. Fine-grained silts and muds accumulated on the seabed, rapidly burying marine organisms and creating the perfect conditions for fossilisation. The result is that Whitby fossils, including Dactylioceras tenuicostatum, are often preserved in remarkable detail, with shell ornamentation and ribbing remaining visible after millions of years.

Collecting and Historical Value

Whitby ammonites have long been prized by both scientists and collectors. During the Victorian era, they were highly sought after for natural history collections and decorative displays. Today, they remain iconic fossils that connect us to the rich geological heritage of Britain’s Jurassic Coast. Owning a specimen of Dactylioceras tenuicostatum is to hold a direct piece of Earth’s deep history, representing both scientific value and timeless natural beauty.

Authenticity and Presentation

• 100% Genuine Fossil Specimen
• Species: Dactylioceras tenuicostatum
• Age: Jurassic, Middle Lias, approx. 180 million years old
• Locality: Runswick Bay, Whitby, United Kingdom
• Supplied with a Certificate of Authenticity
• Scale cube in photos = 1 cm for accurate sizing
• The fossil in the photographs is the exact specimen you will receive

This carefully chosen fossil ammonite is an exceptional example of one of Whitby’s most scientifically significant ammonites. Whether for private display, educational use, or scientific interest, this is a true collector’s specimen that embodies the beauty and history of the Jurassic seas.