3.9" Cretaceous Ammonite (Placenticeras) Fossil - South Dakota

Cretaceous Ammonite (Placenticeras) Fossil - South Dakota #113161

This is 3.9" wide Placenticeras costatum ammonite fossil that was collected from the Pierre Shale of South Dakota. The beautiful suture pattern of this ammonite can easily be seen on the surface. It comes with an acrylic display stand.

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