Ceratitida is an order that contains almost all ammonoid

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

genera from the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

as well as ancestral forms from the Upper

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

, the exception being the phylloceratids which gave rise to the great diversity of post-Triassic

ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

. Ceratitids overwhelmingly produced planospirally coiled discoidal shells that may be evolute with inner whorls exposed or involute with only the outer whorl showing. In a few later forms the shell became subglobular, in others, trochoidal or uncoiled. Sutures are typically ceratitic, with smooth saddles and serrate or digitized lobes. In a few the sutures are goniatitic while in others they are ammonitic.

Taxonomy

* Ceratitida ** Ceratitoidea ** Choristoceratoidea ** Clydonitoidea ** Danubitoidea ** Dinaritoidea ** Lobitoidea ** Meekoceratoidea ** Megaphyllitoidea ** Nathorstitoidea ** Noritoidea ** Otoceratoidea ** Pinacoceratoidea ** Ptychitoidea ** Sageceratoidea ** Tropitoidea ** Xenodiscoidea Only eight superfamilies are shown in the

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part L,(1957), the Otocerataceae, Noritaceae, Ceratitaceae, Arcestaceae, Clydonitaceae, Lobitaceae, Ptychitaceae, and Tropitaceae, in text sequence. The other 10 have been added since, derived from within the original eight.

References

* Arkell et al., 1962, Mesozoic Ammonoidea.

part L, Mollusca 4, Ammonoidea. R.C. Moore (ed)
Paleobiology Database
Guadalupian first appearances Late Triassic extinctions Mollusc orders {{Ceratitida-stub