| Sigmocycloceras Temporal range: M. Ordovician | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Order: | † Orthocerida |
| Family: | † Sactorthoceratidae |
| Genus: | † Sigmocycloceras Kobayashi, 1934 |
Sigmocycloceras is a nautiloid cephalopod discovered in the Middle Ordovician of Korea, said to be similar to Sactorthoceras , and included in the Sactorthoceratidae, but unique in being longitudinally sigmoid and sculpted with transverse annuli.
