These cephalopods existed in the Jurassic period, during Toarcian and possibly even uppermost Pliensbachian age.

[4] Fossils of species contained in this genus have been found in the lower to middle Toarcian of Europe, Canada, Japan, Tibet, Siberia, Africa, or South America.

Under this name were added not only specimens of Cleviceras, but also members of genera Protogrammoceras and Harpoceras.

[1] It differs from Eleganticeras by having stronger ribs and bigger sizes of adults in the case of both dimorphs.

[3] On the other hand, C. chrysanthemum is a possible evolutionary predecessor of Hildaites, but this genus might have also evolved from Protogrammoceras.

Falcoid ribs are bifurcating, or intercalated in diameters of up to 40-50mm, but then they are becoming single and at the end of the adult body chamber, they are striate.

[4] As it has evolved directly from Eleganticeras elegantulum, there exists some transitional forms, that were found in Yorkshire.

While in E. elegantulum, umbilical width growth during ontogeny, in C. exaratum it is constant and in the case of C. elegans, it is decreasing.

[4] Middle one-third of Exaratum Subzone of Falciferum Zone (Toarcian) of Europe, Canada and Siberia and possibly also from north Africa[4][9] C. elegans Sowerby, 1815 'Elegans' is a Latin word for English 'elegant'.

Sloping umbilical wall is forming a funnel shaped umbilicus and also a more compressed whorl section.

They are weak to moderate on microconchs, but stronger in middle growth stage of macroconchs.

Its phylogenetic successor, genus Polyplectus has an oxycone shell with acutely angled venter, without differentiated keel and has also smaller umbilicus.

[3][4] Upper one-third of Exaratum subzone of Falciferum zone (Toarcian) in Europe, NE of Siberia and western Canada.

[3][4] Chrysanthemum is genus of flowering plants from the family Asteraceae, that is often used in symbols in Japan.

chrysanthemum are found in lower to middle Toarcian sediments of Japan, Siberia, Canada and South America.