Dactylioceras Ammonite Fossil Acid Prepared Holzmaden Germany Jurassic Posidonia Shale Genuine Specimen Certificate Authenticity

Description

Genuine Dactylioceras Ammonite Fossil from the Famous Holzmaden Deposits

This beautifully preserved Dactylioceras sp. Ammonite fossil comes from the world-renowned Posidonia Shale Formation of Holzmaden, Baden-Württemberg, Germany, one of the most famous fossil sites on Earth. The specimen has been acid prepared, a specialised preparation technique that removes the surrounding limestone matrix to reveal the ammonite shell in exceptional detail while leaving the fossil naturally raised against the darker shale background.

The result is a striking fossil display piece showing the elegant spiral shell and ribbed structure characteristic of the genus Dactylioceras.

The photograph shows the exact specimen you will receive, making this a carefully selected fossil ideal for collectors, educational collections, and natural history displays.

Full sizing can be seen in the accompanying photographs.

This fossil includes a Certificate of Authenticity lifetime guarantee card, confirming the specimen is a genuine natural fossil.

The Ammonite Species Dactylioceras

Dactylioceras is a well-known genus of ammonite that lived during the Early Jurassic Period, when warm shallow seas covered much of Europe. These marine cephalopods belonged to a diverse group of shelled relatives of modern squid, octopus and cuttlefish.

Scientific classification includes:

• Order: Ammonitida
• Superfamily: Eoderoceratoidea
• Family: Dactylioceratidae
• Genus: Dactylioceras

Ammonites of this genus are particularly important in palaeontology because they are widely used as index fossils for dating Jurassic marine sediments. Different species of Dactylioceras help define biostratigraphic zones within the Early Jurassic.

These ammonites thrived in the ancient European seas approximately 183 to 174 million years ago.

Morphology and Distinctive Shell Features

Ammonites such as Dactylioceras possessed a coiled external shell divided internally into chambers. The living animal occupied the outermost chamber while the inner chambers helped regulate buoyancy.

Characteristic features include:

• Evolute coiling with clearly visible whorls
• Strong ribbing across the shell surface
• Rounded whorl profile
• Distinct spiral growth pattern
• Well-defined chamber divisions internally

The ribbed shell structure strengthened the shell while also creating the visually striking patterns that make ammonite fossils so desirable to collectors.

Acid preparation allows these details to stand out clearly, revealing the natural shell morphology in a dramatic three-dimensional presentation.

Geological Formation and Fossil Preservation

This specimen originates from the Posidonia Shale Formation, one of the most famous fossil-bearing rock units in the world.

Geological details include:

• Formation: Posidonia Shale
• Geological Stage: Toarcian
• Period: Lower Jurassic
• Age: Approximately 183 million years old
• Locality: Holzmaden, Baden-Württemberg, Germany

During the Early Jurassic, the Holzmaden region lay beneath a warm epicontinental sea that covered much of Europe. Periodic oxygen-poor conditions developed on the sea floor, preventing scavengers and allowing dead organisms to be preserved with exceptional detail.

The Posidonia Shale is famous for preserving a wide range of marine fossils including:

• Ammonites
• Belemnites
• Fish
• Marine reptiles such as ichthyosaurs and plesiosaurs
• Crinoids and other marine invertebrates

Because of the unique chemical conditions within the sediment, many fossils from Holzmaden are preserved in remarkable detail.

Acid Preparation Technique

This specimen has undergone acid preparation, a specialised fossil preparation technique commonly used with Holzmaden fossils.

In this process:

• The surrounding limestone matrix is carefully dissolved using controlled acid treatment
• The fossil shell remains intact due to its different mineral composition
• Fine details of the shell are revealed while leaving the fossil raised against the shale surface

This method produces the dramatic contrast and sculptural appearance that makes Holzmaden ammonites highly sought after.

A Classic Jurassic Fossil from a World-Famous Locality

Ammonites from Holzmaden are among the most recognisable fossils in the world. The combination of excellent preservation, historical scientific importance and beautiful preparation makes these fossils particularly desirable.

Dactylioceras specimens from the Posidonia Shale are widely collected because they represent an important group of Early Jurassic ammonites and display striking natural shell patterns.

Whether displayed in a fossil collection, used for educational study, or appreciated as a natural work of prehistoric art, this acid-prepared Dactylioceras ammonite fossil represents an authentic piece of Jurassic marine history.

The fossil shown in the photographs is the exact specimen you will receive.

All fossils sold are 100% genuine natural specimens and include a Certificate of Authenticity lifetime guarantee card.