Hammatoceratoidea

Hammatoceratoidea
Temporal range: early Jurassic–Middle Jurassic
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Suborder: Ammonitina
Superfamily: Hammatoceratoidea
Families

Hammatoceratoidea, formerly Hammatocerataceae is a superfamily of middle Jurassic ammonites (order Ammonitida), erected by Schindewolf (1964) that combines the families Graphoceratidae, Hammatoceratidae, and Soninniidae.[1] The three families were previously included in the Hildocerataceae,[2] and subsequent classifications.[3] 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.

References

  1. Paleobiology Database Hammatoceratoidea entry
  2. Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
  3. D.T. Donovan et al 1981. Classification of Jurassic Ammonitina. The Ammonoidea. Systematics Association special volume 18.
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