''Octamerella'' is an extinct genus of prehistoric nautiloids from the

oncocerid The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are ...

family

Hemiphragmoceratidae Hemiphragmoceratidae is a family of endogastrically brevconic oncocerids characterized by elaborately visored apertures in which the hyponomic sinus in mature specimens is on a spout-like process and there may be lateral and dorsal salients. (S ...

that lived in what is now Europe and North America during the Middle

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

. ''Octamerella'' has a breviconic shell and a mature aperture that is contracted so as to have four pairs of dorsolateral sinuses, four on each side, and a narrow mid-dorsal salient. The two ventral-most sinus pairs are typically the largest, while the dorsal-most pair is short and wide, forming a circular opening.Sweet, 1964

References

* Sweet, W.C. 1964. Nautilodea-Oncocerida; Treatise on Invertebrate Paleontology, Part K; Geol Soc of America and Univ Kansas Press, Teichert & Moore eds. * Sepkoski, J.J. Jr. 2002. A compendium of fossil marine animal genera. D.J. Jablonski & M.L. Foote (eds.). ''Bulletins of American Paleontology'' 363: 1–560
Sepkoski's Online Genus Database (CEPHALOPODA)

Fossilworks: Octamerella
Oncocerida Silurian cephalopods Silurian animals of Europe Silurian cephalopods of North America Prehistoric nautiloid genera {{Silurian-animal-stub