†Cyrtactinoceras Hyatt in Zittel 1900 (mollusk)
Cephalopoda - Orthocerida - Proteoceratidae
Parent taxon: Proteoceratidae according to C. Teichert et al. 1964
Sister taxa: Archigeisonoceras, Baykonuroceras, Ephippiorthoceras, Euorthoceras, Gangshanoceras, Gorbyoceras, Isorthoceras, Liulinoceras, Mesnaquaceras, Metephippiorthoceras, Monomuchites, Orthonybyoceras, Paraproteoceras, Proteoceras, Pseudoliolinoceras, Stereospyroceras, Tofangoceras, Transorthoceras, Treptoceras, Ulmioceras
Subtaxa: none
Ecology: nektonic carnivore