''Graphoceras'' is an extinct

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttle ...

genus included in the hildoceratacean family Graphoceratidae that lived during the

Aalenian The Aalenian () is a subdivision of the Middle Jurassic Epoch/ Series of the geologic timescale that extends from about 174.1 Ma to about 170.3 Ma (million years ago). It was preceded by the Toarcian and succeeded by the Bajocian. Stratigraphic ...

and

Bajocian In the geologic timescale The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relatin ...

stages, 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 Mya. The J ...

in what is now Europe, north Africa, and Iran. ''Graphoceras'' produced a compressed, involute shell with a raised umbilical edge and sinuous ribbing.

References

* Arkell ''et al.'', 1957. Mesozoic Ammonoidea (L264), Treatise on Invertebrate Paleontology Part L. Geological Society of America and University of Kansas Press. Middle Jurassic ammonites Ammonites of Europe Hildoceratoidea Ammonitida genera {{Ammonitina-stub