RARE: NOSTOCERAS OTSUKAI Heteromorph Ammonite Fossil – Campanian Cretaceous – Madagascar – Certified Authentic Specimen

Description

RARE NOSTOCERAS OTSUKAI – HETEROMORPH AMMONITE FOSSIL FROM MADAGASCAR (CRETACEOUS: CAMPANIAN)

This rare and striking fossil is a beautifully preserved Nostoceras otsukai, a heteromorph ammonite from the Campanian Stage of the Late Cretaceous, collected in Madagascar. Heteromorph ammonites like Nostoceras are prized for their bizarre, uncoiled shell structures which deviate from the typical spiral forms seen in most ammonites.

This particular specimen comes from the Alice Purnell Collection, known for its premium-quality and ethically sourced fossils. You will receive the exact specimen shown in the photographs. Please see the included photo with a 1cm scale cube for full sizing and detail.

As with all our items, this fossil is 100% genuine and includes a Certificate of Authenticity.

Fossil Identification:

• Species: Nostoceras otsukai
• Genus: Nostoceras
• Family: Nostoceratidae
• Superfamily: Turrilitoidea
• Order: Ammonitida
• Class: Cephalopoda
• Phylum: Mollusca
• Common Name: Heteromorph Ammonite

Geological and Stratigraphic Context:

• Geological Period: Cretaceous
• Stage: Campanian (Late Cretaceous, approx. 83.6 – 72.1 million years ago)
• Locality: Madagascar (exact site unspecified)
• Depositional Environment: Likely marine shelf environments along the western margin of the Mozambique Channel; deposition in soft calcareous or silty sediments conducive to fossil preservation
• Stratigraphic Significance: Campanian-age ammonites such as Nostoceras are excellent zonal fossils used in global stratigraphic correlation

Morphological Features:

Nostoceras otsukai is a heteromorph ammonite characterised by a loosely coiled, helical spire followed by a recurved body chamber. This form is interpreted as an adaptation for a slow-moving or even planktonic lifestyle, possibly floating or hovering near the seafloor. Shell ornamentation may include fine ribbing and tubercles (knobs), with a distinctive hook-like curvature typical of the genus.

The complex, non-planispiral coiling and ornate shell make it both scientifically valuable and visually striking—ideal for collectors or educational display.

Scientific Importance:

Heteromorph ammonites like Nostoceras are important for understanding the evolutionary experimentation during the Late Cretaceous. Their widespread distribution and unique forms help paleontologists track global sea levels, climates, and extinction patterns leading up to the end-Cretaceous mass extinction. Nostoceras otsukai was originally described based on specimens from Japan, with closely related forms found in Madagascar, indicating wide paleogeographic distribution.

Provenance:

This piece hails from the Alice Purnell Collection, a respected source of scientifically vetted and museum-grade fossils. Each fossil from this collection is hand-selected and expertly prepared.

Item Details:

• Rare heteromorph ammonite fossil (Nostoceras otsukai)
• Geological age: Campanian, Late Cretaceous
• Location: Madagascar
• Exact specimen shown in photos
• Includes Certificate of Authenticity
• Professionally prepared and ready for display
• 1cm scale cube for accurate size reference

Add a unique and scientifically significant fossil to your collection with this rare Nostoceras otsukai specimen—an excellent showcase of Cretaceous heteromorph evolution and artistry from nature.