This Specimen has been sold.
5 Inch, Scarce Desmoceras Ammonite
Desmoceras is a genus of ammonite from Madagascar much less frequently seen than the common Cleoniceras. It's much thicker and wider with this specimen being almost an inch and a half thick at it's widest and 5 inches in diameter. It's Early Cretaceous (Albian Stage) in age or approximately 110 million years old.
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.