Hammatoceratoidea, formerly Hammatocerataceae was a superfamily of middle Jurassic

ammonites Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

erected by Schindewolf in 1964 that combined the families

Graphoceratidae Graphoceratidae is an extinct family of ammonites in the order Ammonitida, which lived during the Jurassic. Distribution Fossils are found in the Jurassic marine strata of Canada, France, Germany, Hungary, Italy, Morocco, Saudi Arabia, Spain and ...

, Hammatoceratidae, and

Sonniniidae Sonniniidae is a diverse family of Middle Jurassic ammonites ranging from those with stout evolute shells to those whose shells are sharply rimmed, oxyconic. The keel, which runs along the middle of the venter, is typically hollow. Sutures vary f ...

. The three families were previously included in the

Hildoceratoidea Hildoceratoidea, formerly Hildoceratacaea, is a superfamily of compressed or planulate ammonites, some tending to develop acute outer rims; generally with arcuate or sigmoidal ribs. Aptichus were found in place are double-valved.Arkell ''et al.' ...

, however subsequent classifications have moved the families back into Hildoceratoidea.D.T. Donovan ''et al.'', 1981. Classification of Jurassic Ammonitina. The Ammonoidea. Systematics Association special volume 18. 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. Hammatoceratoids were suggested to be derived from the family Phymatoceratidae of the

, beginning with the Hammatoceratidae near the end of the Early Jurassic.

References

Jurassic ammonites Early Jurassic first appearances Middle Jurassic extinctions Obsolete animal taxa Ammonitina {{Ammonitina-stub