Gonatite Gonioclymenia sp. Fossil – Genuine Devonian Ammonoid from Morocco

Authentic Gonioclymenia sp. Gonatite Fossil – Devonian Ammonoid from Morocco

This exquisite Gonatite Fossil (Gonioclymenia sp.) is an authentic ammonoid specimen from the Late Devonian period, approximately 370 million years old, discovered in the fossil-rich layers of Morocco’s Anti-Atlas region. Belonging to the extinct order Clymeniida, Gonioclymenia represents one of the last great evolutionary branches of ammonoids before the mass extinction at the end of the Devonian. Each fossil provides a remarkable glimpse into marine life from a time long before the first dinosaurs, when much of the planet was covered by shallow tropical seas teeming with early fish, corals, and cephalopods.

All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. The photograph shows the exact piece you will receive, displayed beside a 1 cm scale cube for accurate sizing. Please refer to the photo for full size details.

Geological Age and Provenance

This fossil originates from the Upper Devonian (Famennian Stage) strata of southern Morocco, within the Anti-Atlas sedimentary basin. During the Devonian period, roughly 419–359 million years ago, this region formed part of the Gondwanan continental margin, characterised by extensive marine carbonate platforms. These warm, nutrient-rich seas were ideal for cephalopods, brachiopods, crinoids, and trilobites, resulting in exceptional fossil preservation across Morocco’s Devonian deposits.

The Famennian Stage represents the final phase of the Devonian—an era of ecological transition and mass extinction that reshaped global marine ecosystems. Gonioclymenia, along with other clymeniid ammonoids, flourished during this time, only to disappear at the Hangenberg Event, which marks one of Earth’s most significant biotic crises.

Taxonomy and Scientific Classification

• Kingdom: Animalia

• Phylum: Mollusca

• Class: Cephalopoda

• Subclass: Ammonoidea

• Order: Clymeniida

• Family: Gonioclymeniidae

• Genus: Gonioclymenia

• Geological Stage: Upper Devonian (Famennian)

Clymeniid ammonoids such as Gonioclymenia are unique among Devonian cephalopods due to their inverted siphuncle position—running along the dorsal margin of the shell, rather than the ventral side as seen in most ammonites. This structural adaptation makes them particularly interesting from an evolutionary perspective, offering insight into the diversity and experimentation of early ammonoid morphology.

Morphological Characteristics

The fossil exhibits the characteristic planispiral coiling of ammonoids, with a gently compressed whorl cross-section and fine, radial ribbing patterns across its surface. The chambers (camerae) and septa are well-defined, and in some examples, the suture lines may be faintly visible. The shell’s natural calcite and iron oxide preservation lend it beautiful earthy tones, ranging from grey and cream to deep ochre.

The ornamentation and curvature of Gonioclymenia indicate a nektonic lifestyle—this creature was a free-swimming predator, likely feeding on small crustaceans and other invertebrates in open marine waters. The structure of its shell allowed it to control buoyancy and movement using gas and liquid within the internal chambers, much like modern-day nautiluses.

Palaeoenvironment and Depositional Setting

During the Late Devonian, Morocco lay within tropical latitudes, where warm, shallow seas promoted carbonate sedimentation and exceptional fossil preservation. The Clymeniida ammonoids are often found within fine-grained limestones and marls, deposited in calm marine environments with low sediment disturbance. These conditions enabled delicate features such as shell patterns and internal chamber structures to be preserved in remarkable detail.

The extinction event at the end of the Famennian, caused by global anoxia (oxygen depletion) and rapid climate shifts, wiped out most ammonoid lineages. Fossils like this Gonioclymenia sp. represent some of the last ammonoids of the Devonian, making them both scientifically significant and historically poignant.

Collector and Educational Value

This fossil is a scientifically important and visually striking specimen ideal for collectors, educators, and display. As a representative of the final Devonian ammonoid radiation, Gonioclymenia stands as an enduring symbol of evolutionary innovation and extinction. Its distinct coiling, elegant ribbing, and smooth polish make it both an informative teaching piece and a timeless display fossil.

Each specimen from Morocco’s Devonian formations is a window into Earth’s deep past, capturing the beauty and complexity of marine life that flourished hundreds of millions of years before modern species evolved.

Authenticity and Presentation

All of our fossils are 100% genuine specimens and include a Certificate of Authenticity verifying their age, origin, and scientific identification. The photograph shows the exact Gonioclymenia sp. Gonatite Fossil from Morocco you will receive, with a 1 cm scale cube provided for accurate measurement—please refer to the image for complete details.

This genuine Devonian ammonoid fossil from Morocco is a striking example of ancient marine evolution—a rare and beautiful piece of natural history from the Famennian seas, expertly preserved and ready for display.