Goniatitis choctawensis cephalopod from Oklahoma

Goniatites were common thoughout the Paleozoic until going extinct during the Permian. they were related to true Ammonites but often were considered Ammonoids. The specimen below comes from the Caney Shale (Mississippian epoch, Serpukhovian stage) near Fittstown, Oklahoma.

The suture pattern is very well defined