7.3" Cretaceous Heteromorph Ammonite (Didymoceras) - South Dakota

Cretaceous Heteromorph Ammonite (Didymoceras) - South Dakota #306621

This is a gorgeous and extremely uncommon, 7.3" wide heteromorph ammonite (Didymoceras nebrascense) fossil collected from the Cretaceous-aged Pierre Shale of South Dakota. The rock has been meticulously worked away to expose this incredible ammonite specimen. Portions of the iridescent shell can be found around much of the ammonite.

Comes with an acrylic/metal display stand.

There are multiple repaired cracks throughout this specimen, along with some areas of gap fill and surface restoration. The smallest half of this ammonite is likely a composite.

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.

More about ammonites