18" Polished Ammonite Fossil From Madagascar - Giant Specimen!

This is a massive 18" wide polished ammonite fossil of the species Argonauticeras besairiei, collected near Ambatolafia, Madagascar. It makes for a very impressive display on the included metal display stand.

You rarely get ammonites of this size and condition of out Madagascar. While it does have repair work, this is to be expected on large ammonites that will be found already fractured in the ground. There is a small amount of purple iridescent flash on some areas of the specimen. All of the rock has been carefully removed from the chamber on the very end of the ammonite adding to its appeal.

Ammonites were predatory cephalopod mollusks that resembled squids with spiral shells. They are more closely related to living octopuses, though their shells resemble that of nautilus species. True ammonites appeared in the fossil record about 240 million years ago during the Triassic Period. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

What an ammonite would have looked like while alive.
What an ammonite would have looked like while alive.

Argonauticeras besairiei
Ambatolafia, Mahajanga Province, Madagascar
18" wide, 6" thick, 59 lbs
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