This Specimen has been sold.
5.3 Inch Perisphinctes Ammonite - Jurassic
This is a classic Late Jurassic ammonite fossil from Madagascar. It's in nice shape and still has much of the white shell remaining unlike many that are just preserved as internal casts.
Ammonites were predatory mollusks that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.