Paradakeoceras is an early Ordovician

Ordovician

The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

 cephalopod belonging to the nautiloid order Ellesmerocerida

Ellesmerocerida

The Ellesmerocerida is a order of primitive cephalopods belonging to the subclass Nautiloidea with a widespread distribution that lived during the Late Cambrian and Ordovician.-Morphology:...

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Morphology

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

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 Spirula...

 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

Dakeoceras is a simple cyrtoconic ellesmeroceratid genus, all known species of which come from the Lower Canadian of North America....

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

Quebecoceras

Quebecoceras is an extinct genus from the nautiloid order Ellesmerocerida that lived during the Gasconadian Stage at the beginning of the Early Ordovician....

and has a reduction in the rate of expansion similar to that of Dakeoceras.