Description
ZETOCERAS PHYLLOCERAS Fossil Ammonite – Callovian Stage, Middle Jurassic, Maintirano Region, Madagascar
This exquisitely preserved ammonite fossil represents the genus Zetoceras, a phylloceratid cephalopod from the Callovian stage of the Middle Jurassic, approximately 166 to 163 million years ago. Recovered from the fossil-rich limestone beds of Maintirano, Madagascar, this specimen is a rare and beautiful example of an ancient marine predator with refined shell morphology.
Fossil Type & Species:
- Type: Invertebrate Fossil (Ammonite Shell)
- Genus: Zetoceras (Phylloceratina)
- Related Group: Phylloceras genus complex (not to be confused with direct species designation)
- Order: Ammonitida
- Suborder: Phylloceratina
- Superfamily: Phylloceratoidea
- Family: Phylloceratidae
- Geological Age: Callovian Stage, Middle Jurassic
- Described by: Neumayr, 1875 (for Zetoceras)
Geological & Stratigraphic Details:
- Location: Maintirano, Western Madagascar
- Formation: Marine limestone beds rich in ammonite fauna
- Geological Stage: Callovian (Middle Jurassic)
- Age: ~166–163 million years ago
- Depositional Environment: Open marine shelf with fine-grained limestone and marl deposits preserving aragonitic shell material in exceptional detail
- Biozone: Callovian ammonite-bearing marine sequences (specific zonation unconfirmed)
Morphology & Features: This Zetoceras specimen displays:
- Highly involute, smooth shell with narrow umbilicus
- Flattened flanks and gently rounded venter
- Fine ornamentation and visible suture lines when exposed or polished
- Natural colours ranging from sandy beige to brown and reddish tones depending on mineral content
- Sometimes polished for aesthetic enhancement and to reveal internal chamber patterns
Notable: Zetoceras, often associated with or misattributed to Phylloceras, is part of the phylloceratid lineage, characterised by simple but tightly coiled shells with complex sutures. Its presence in Madagascar’s Middle Jurassic strata marks a rich marine ecosystem during a key evolutionary phase in ammonite development.
Specimen Details:
- Origin: Maintirano, Madagascar
- Genus: Zetoceras (Phylloceratina lineage)
- Fossil Type: Ammonite Shell (Invertebrate)
- Geological Stage: Callovian, Middle Jurassic
- Size Reference: Scale rule square = 1cm (see photo for full sizing)
- Note: You will receive the exact fossil shown in the photographs
Authenticity & Quality: Every specimen is carefully selected for quality, preservation, and scientific value. This fossil is 100% genuine and comes with a Certificate of Authenticity. It has not been reconstructed or artificially enhanced.
Why Choose This Fossil? This rare Zetoceras ammonite is perfect for:
- Jurassic fossil collectors
- Educational and research use
- Natural history museums and displays
- Beautiful and meaningful gifts for fossil enthusiasts
Shipping & Packaging: We provide secure, eco-conscious packaging and fast, tracked shipping. Each item is safely packed to ensure it arrives in excellent condition.
Own a rare and elegant relic from the Jurassic seas of Madagascar with this genuine Zetoceras ammonite fossil.
All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.
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