Oppeliidae are compressed to oxyconic, sculptured

Haploceratoidea Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of Ammonoidea, ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, listed below. Haploceratoidea begins ...

, either unkeeled, unicarinate, bicarinate, or tricarinate; with sutures in great variety, but ribbing usually more or less falcoid or falcate. The Oppeliidae is the principal family of the

, with the longest duration, extending from the Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

(

Bajocian In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.9 ±0.8 Ma to around 168.2 ±1.2 Ma (million years ago). The Bajocian Age succeeds the Aalenian Age and precedes the Bathonia ...

) to the Upper

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

(

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

) Their derivation is from 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.' ...

Subfamilies

Nine subfamilies are recognized, the first eight of which are included in the earlier Treatise, Part L. They are the: :

Oppeliinae Oppeliinae is a subfamily within the Oppeliidae Oppeliidae are compressed to oxyconic, sculptured Haploceratoidea, either unkeeled, unicarinate, bicarinate, or tricarinate; with sutures in great variety, but ribbing usually more or less falcoi ...

Hecticoceratinae Hecticoceratinae is a subfamily of oppeliids from the Middle and Upper Jurassic typically with strong falcoid or falcate ribbing that covers whorl sides completely. Venters are usually keeled and may be tricarinate.Treatise on Invertebrate Paleo ...

: Distchoceratinae : Teramelliceratinae :

Phlycticeratinae Phlycticeratinae is an ammonite subfamily included in the Oppeliidae established for the genus '' Phlycticeras''. Although there seems to be some affinity with Stephanoceratoidea it is most likely descended from some bathonian member of the Op ...

Streblitinae Streblitinae is a subfamily of Upper Jurassic and Lower Cretaceous ammonites within the family Oppeliidae characterized by compressed, involute shells; typically oxycones with complex sutures. Includes '' Streblites'', '' Pseudoppelia'', and '' ...

Mazapilitinae Mazapilitinae is a subfamily of Upper Jurassic ammonites included in the Oppeliidae. Shells are involute; venter rounded or gently tabulate; ribbing coarse, fold-like, branching.W.J. Arkell ''et al.'', 1957 Mesozoic Ammonoidea. Treatise on Inver ...

: Aconeceratinae : Binneyitinae The Binneyitinae was added by Donovan ''et al'', 1981, transferred from the

Stephanoceratoidea Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed ...

References

* D.T Donavan, J.H. Callomon, and M.K Howarth. 1981. Classification of the Jurassic Ammonitina. In The Ammonoidea. M.R. House and J.R. Senior, eds. Systematics Assoc. Pub Academic Press. *

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 Mollusca 4, Mesozoic Ammonoidea. R.C Moore (ed.); Geol. Society of America and Univ. Kansas Press. (1957) Ammonitida families Haploceratoidea Bajocian first appearances Cenomanian extinctions {{Ammonitina-stub