Kingdom Animalia Class Cephalopoda Order †Ammonitida Rank Superfamily | Phylum Mollusca Subclass †Ammonoidea Suborder †Ammonitina | |
Similar Graphoceratidae, Hildoceratoidea, Acanthoceratoidea, Desmocerataceae | ||
Hammatoceratoidea, formerly Hammatocerataceae is a superfamily of middle Jurassic ammonites (order Ammonitida), erected by Schindewolf (1964) that combines the families Graphoceratidae, Hammatoceratidae, and Soninniidae. The three families were previously included in the Hildocerataceae, and subsequent classifications. In more recent classifications Hammotocerataceae are referred to as Hammatoceratoidia.
Shells of hammatoceratoids are variably evolute or involute, ribbed at least in the early growth stage; cross section typically compressed (higher than wide); venter commonly with a median keel.
Hammatoceratoidea is derived from the family Phymatoceratidae of the Hildoceratoidea, beginning with the Hammatoceratidae near the end of the Early Jurassic.