Dakeoceras
''Dakeoceras'' is a genus of simple cyrtoconic ellesmeroceratid cephalopods in the fossil record. All known species come from the Lower Canadian epoch ( Gasconadian) of North America. The Dakeoceras shell is an endogastric cyrtocone with the siphuncle on the concave, ventral, side; moderately curved and expanded in the juvenile stages which become reduced in the adult. Forms in which the cross section is broadened, with the venter becoming flattened, are separated as '' Paradakeoceras''. '' Quebecoceras'' is also similar but for its circular cross section and more persistent rate of expansion and curvature. ''Levisoceras ''Levisoceras'' is a genus of early Ordovician ellesmerocerid cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively ...'' is more compressed, more strongly curved, and has a higher rate of expansion especially in the vert ...
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Paradakeoceras
''Paradakeoceras'' is a genus of early Ordovician cephalopods belonging to the nautiloid order Ellesmerocerida. Morphology The shell of ''Paradakeoceras'' is an expanding endogastric cyrtocone with the siphuncle situated near the shell's concave margin. A raised ring exists at the base of the body chamber, which is often preserved as a mould. ''Paradakeoceras'' was named by Flower, 1964, for species previously included in ''Dakeoceras'' in which the cross section is broadened with consequent loss of lateral lobes in the suture. ''Paradakeoceras'' shows a flattening of the venter which distinguishes it from ''Quebecoceras'' and has a reduction in the rate of expansion similar to that of ''Dakeoceras''. References

Prehistoric nautiloid genera Ordovician cephalopods Ordovician cephalopods of North America Ellesmerocerida {{paleo-Nautiloidea-stub ...
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