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Rastellum fossil oyster – ‘fossil alien’ bivalve – cretaceous period – marovoay, madagascar – 100% genuine with certificate

Rastellum fossil oyster – ‘fossil alien’ bivalve – cretaceous period – marovoay, madagascar – 100% genuine with certificate

Original price was: £18.00.Current price is: £16.20.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity

 

Specimen: Rastellum oyster bivalve (fossil Alien)

Age: Cretaceous

Location: Marovoay, Mahajanga district, Madagascar

Size (picture scale cube=1cm): 67 x 26 x 47mm (2.64 x 1.02 x 1.85 inches)

 

More commonly known as ‘Fossil Alien’s these amazing bivalves are actually oyster shells.  Bivalves are bilaterally symmetrical molluscs having two calcareous, asymmetrical shells (valves) – they include the clams, oysters, and scallops. In most bivalves, the two shells are mirror images of each other (the major exception is the oysters). They occur in marine, estuarine, and freshwater environments.

 

ACTUAL AS SEEN: The image shows the EXACT specimen you will receive. The specimen has been carefully hand selected and photographed. Measurements are as accurate as possible, though be aware measuring precise dimensions can be difficult from irregular shaped items. Whilst we portray colours as close to life-like as we can, colours will vary if taken in sunlight, indoors, from monitor to monitor and device to device. Once this specimen is sold, we will update this listing with new similar selected item, with a new photo and dimensions.

(Actual as seen)

Only 1 left in stock

SKU: FP9674 Category:

Description

This listing features a genuine fossil specimen of Rastellum, a strikingly sculpted extinct oyster bivalve, affectionately known in the fossil world as a ‘Fossil Alien’ due to its distinctive ridged and curved appearance. This fossil originates from Cretaceous-aged marine deposits in Marovoay, Mahajanga District, Madagascar, and dates back approximately 100 to 94 million years ago.

Rastellum is a genus of oyster-like bivalves in the family Ostreidae. These prehistoric molluscs had highly ribbed, curved shells that interlocked with one another and grew in dense clusters in warm, shallow marine environments. Their bizarre appearance, with deep fluted ridges and tapering ends, has earned them the nickname “fossil aliens” among collectors and enthusiasts.

Bivalves are molluscs with two hinged shells and include modern clams, oysters, and scallops. While most bivalves are symmetrical and the two halves mirror one another, oysters like Rastellum break this rule—having asymmetrical shells adapted for anchoring to surfaces such as rocks and reefs.

Geological Context: This fossil was recovered from the Cretaceous marine limestones of northern Madagascar, in the region of Marovoay. During the Late Cretaceous, Madagascar was isolated from other landmasses and surrounded by tropical seas, which provided excellent conditions for marine life and subsequent fossilisation.

Key Details:

  • Specimen: Rastellum Oyster Bivalve (‘Fossil Alien’)
  • Fossil Type: Bivalve mollusc shell fossil
  • Age: Cretaceous Period (~100–94 million years ago)
  • Location Found: Marovoay, Mahajanga District, Madagascar
  • Condition: Naturally preserved, ridged shell structure
  • Authenticity: 100% genuine specimen, supplied with a Certificate of Authenticity
  • Scale: See 1cm cube in image for accurate sizing
  • Photo: The exact specimen shown is what you will receive

ACTUAL AS SEEN: Each fossil is carefully hand-selected and professionally photographed. While dimensions are as accurate as possible, fossils may have irregular shapes. Colour may vary based on lighting and monitor settings. Once this specimen sells, the listing will be updated with a new unique item and new photographs.

Please Note:

  1. Images may update in your basket if the item sells and a new specimen is listed.
  2. We recommend saving or screenshotting your purchased item photo for reference.

Scientific & Display Value: This fascinatingly detailed Rastellum fossil is a wonderful specimen for collectors, educators, and anyone intrigued by Earth’s prehistoric oceans. The unusual, almost alien appearance of this bivalve makes it a great conversation starter and a beautiful display piece.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity

Fast & Secure Shipping – Carefully packaged and promptly dispatched.

Own a truly unique and naturally artistic relic of Earth’s Cretaceous seas with this authentic Rastellum ‘Fossil Alien’ oyster from Madagascar.

 

Additional information

Era

Cretaceous
Origin

Madagascar

Cretaceous Information

The Cretaceous Period (145–66 million years ago) was the final era of the Mesozoic, marked by the dominance of dinosaurs and the rise of flowering plants. It had a warm, greenhouse climate, with high sea levels that created vast shallow inland seas. Marine life flourished, including mosasaurs, ammonites, and rudist reefs, while the land was ruled by iconic dinosaurs like Tyrannosaurus rex, Triceratops, and Spinosaurus. Mammals and birds diversified, and insects thrived. The period ended with the mass extinction event, likely caused by an asteroid impact, wiping out the dinosaurs and paving the way for the rise of mammals in the Cenozoic.

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