词条 | Oncoceras |
释义 |
| fossil_range = Mid -Late Ordovician | image = | regnum = Animalia | phylum = Mollusca | classis = Cephalopoda | subclassis = Nautiloidea | ordo = Oncocerida | familia = | genus = Oncoceras | genus_authority = Hall,1847 }} Oncoceras is a genus of oncocerids, family Oncoceratidae from the middle and upper Ordovician of North America and Europe. The shell, or conch, of Oncoceras is relatively short, a curved, compressed brevicone with a maximum width in the phragmocone just behind the body chamber, narrowing toward the aperture. The siphuncle is small, necks recurved. References
6 : Prehistoric nautiloid genera|Ordovician cephalopods|Middle Ordovician first appearances|Late Ordovician extinctions|Paleozoic life of the Northwest Territories|Paleozoic life of Quebec |
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