†Sigmocycloceras Kobayashi 1934 (mollusk)
Cephalopoda - Orthoceratoidea - Sactorthoceratidae
Parent taxon: Sactorthoceratidae according to B. Kröger et al. 2007
Sister taxa: Braulioceras, Cartersoceras, Centroonoceras, Glenisteroceras, Leptoplatophrenoceras, Murrayoceras, Sactorthoceras, Scipioceras, Wennanoceras, Wolungoceras
Subtaxa: none
Ecology: fast-moving nektonic carnivore