Posttornoceratinae is one of two subfamilies of the Posttornoceratidae family, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses and cuttlefish, and more distantly to the nautiloids. References The Paleobiology Database accessed on 10/01/07 Posttornoceratidae