''Paradakeoceras'' is a genus of early Ordovician cephalopods belonging to the nautiloid order

Ellesmerocerida The Ellesmerocerida is an order of primitive cephalopods belonging to the subclass Nautiloidea with a widespread distribution that lived during the Late Cambrian and Ordovician. Morphology The Ellesmerocerida are characterized by shells that ...

Morphology

The shell of ''Paradakeoceras'' is an expanding endogastric cyrtocone with the

siphuncle The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...

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 ''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 ...

'' 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