The Ochetoceratinae 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 falcoid or falcate. The Oppeliidae is the principal famil ...

from the Upper

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 Mya. The J ...

, shells of which are typically oxycones with a tricarinate venter and falcoid ribbing, commonly divided by a median lateral groove or fillet. The median (middle) keel is the tallest. The Ochetoceratinae may be polyphyletic, derived from both the

and

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 ...

as suggested by differences in the included genera.

Description

The median lateral groove is well developed in ''Ochetoceras'' and ''Fehlmanites'', less discernible in ''Cymaceras'', but missing or difficult to make out in the other four.

References

*W.J. Arkell, et al. 1957 Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas Press. *D.T. Donovan, J.H. Callomon, and M.K. Howarth, 1981. Classification of the Jurassic Ammonitina. The Systematica Association Special Volume no. 18. The Ammonoidea. Academic Press. {{Taxonbar, from=Q18355972 Ammonitida Jurassic ammonites