Hammatoceratoidea

Hammatoceratoidea, formerly Hammatocerataceae was a superfamily of middle Jurassic ammonites erected by Schindewolf in 1964 that combined the families Graphoceratidae, Hammatoceratidae, and Sonniniidae.[1] The three families were previously included in the Hildoceratoidea,[2] however subsequent classifications have moved the families back into Hildoceratoidea.[3]

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 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.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.