''Dakeoceras'' is a genus of simple cyrtoconic ellesmeroceratid

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 marine animals are characterized by bilateral body symmetry, a prominent head ...

s 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 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 ...

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 vertical plane.

External links

* Flower, R.H. 1964. The Nautiloid Order Ellesmerocerida (Cephalopoda); Memoir 12, New Mexico Bureau of Mines and Mineral Resources, Socorro N.M. * W. M. Furnish & Brian F. Glenister, 1964. Nautiloidia—Ellesmerocerida. Treatise on Invertebrate Paleontology, Part K. Geological Society of America, Teichert and Moore (eds). Prehistoric nautiloid genera Ordovician cephalopods Ordovician cephalopods of North America Ellesmerocerida {{paleo-Nautiloidea-stub