''Centroonoceras'' is a middle Ordovician cyrtoconic nautiloid cephalopod, otherwise similar to the orthoconic '' Sactorthoceras'' and also included in the Sactorthoceratidae. It was named by Kobayashi, 1934, and has been found in Korea and in New York state in the eastern U.S. ''Centroonoceras'' is characterized by a smooth, gently expanding shell with a moderate but definite curvature and circular cross section. Septa are close spaced. The siphuncle is subcentral, as in ''Sactorthoceras''. Segments are subfusiform; generally straighter on the dorsal side and more expanded on the ventral side. No cameral or endosiphuncle deposits are known.

References

* Walter C Sweet 1964. Nautiloidea-Orthocerida; Treatise on Invertebrate Paleontology, Part K. Geol. Soc. of America and Univ. Kansas Press. Prehistoric nautiloid genera Paleozoic life of Newfoundland and Labrador {{paleo-cephalopod-stub