Description
Rare Zacatecas Ammonite Fossil from Mexico
This is an exceptional and rare Zacatecas ammonite fossil from the Albian stage of the Early Cretaceous period (approximately 113–100 million years ago). Collected in the historic fossil-rich region of Zacatecas, Mexico, this specimen offers a unique glimpse into the marine life that once thrived in the shallow seas that covered the area during the Cretaceous. The fossil shown in the photographs is the exact piece you will receive, pictured with a 1 cm scale cube for reference. As with all of our fossils, it is a 100% genuine specimen and comes complete with a Certificate of Authenticity.
Geological Context – Albian Stage, Cretaceous of Mexico
During the Albian stage of the Early Cretaceous, vast shallow seas spread across much of Mexico, forming a rich depositional environment for marine invertebrates, including ammonites, belemnites, and bivalves. The sediments that accumulated in this region were primarily composed of marine limestones and marls, which provided ideal conditions for fossil preservation.
The Zacatecas locality is particularly significant as it lies within one of Mexico’s renowned Cretaceous basins, offering a valuable window into the evolutionary and paleogeographic history of the Tethyan realm. Fossils from this region allow paleontologists to correlate North and South American strata with those of Europe and Africa, helping to refine the global timescale of the Albian.
Scientific Classification
- Fossil Type: Ammonite
- Age: Albian, Early Cretaceous (c. 113–100 million years ago)
- Geological Stage: Albian
- Locality: Zacatecas, Mexico
- Order: Ammonitida
- Superfamily: Desmoceratoidea (commonly represented in Mexican Albian faunas)
- Family: Various lineages represented, with Zacatecas yielding both smooth-shelled and ribbed forms
Morphological Features
Ammonites from Zacatecas are renowned for their distinctive shell morphologies. This specimen displays the key features typical of Cretaceous ammonites:
- A coiled, planispiral shell with well-preserved whorls.
- Ornamentation ranging from fine ribbing to smooth flanks depending on the lineage.
- Sutures with highly complex, crenulated patterns, characteristic of Cretaceous ammonites.
- A natural patina that highlights the growth lines and overall shell form.
These traits make Zacatecas ammonites not only scientifically important but also visually appealing, highly prized by fossil collectors worldwide.
Paleontological Importance
Ammonites such as this were free-swimming cephalopods, closely related to modern squid and cuttlefish. They are considered one of the most important groups of index fossils, used by geologists to date and correlate rock layers across different regions of the world.
The Albian stage was a dynamic period in Earth’s history, with major evolutionary turnovers among ammonites. Their rapid speciation and global distribution make them ideal for reconstructing ancient ocean connections and biogeographic patterns. A fossil from Zacatecas is thus more than a collector’s item – it represents a piece of the evolutionary puzzle of the Cretaceous seas.
Depositional Environment – Shallow Marine Seas of Mexico
The ammonites of Zacatecas lived in warm, shallow, tropical seas that formed part of the Tethys Ocean system. These seas were nutrient-rich, supporting diverse marine ecosystems. Alongside ammonites, the deposits often contain fossils of gastropods, bivalves, and other molluscs, painting a picture of a thriving Early Cretaceous community.
Sedimentation in the region was dominated by marine limestones interbedded with marl, providing exceptional preservation conditions. This ensures that fossils from the region retain intricate details of their shell morphology.
Collector and Display Value
This Zacatecas ammonite fossil is a rare and scientifically significant specimen that will appeal to both serious collectors and enthusiasts of natural history. Its geological importance, combined with its striking aesthetic, makes it an ideal piece for display, teaching, or as part of a curated fossil collection.
Every fossil we offer has been carefully selected for authenticity, condition, and scientific relevance. This specimen comes with a Certificate of Authenticity, ensuring peace of mind for your investment in a genuine piece of Earth’s deep history.
Key Details
- Fossil Type: Ammonite
- Age: Albian, Early Cretaceous (c. 113–100 million years old)
- Locality: Zacatecas, Mexico
- Geological Context: Albian marine limestones of Mexico’s Cretaceous basins
- Supplied with Certificate of Authenticity
- Exact specimen shown in photographs with 1 cm scale cube
This is a remarkable opportunity to own a genuine Zacatecas ammonite fossil, a rare and beautiful relic of the Cretaceous seas of Mexico.
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