''Praeactinocamax plenus'' is an extinct

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 ...

. Its fossils are found in the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

. It has been described by Blainville in 1827 under the name ''Belemnites plenus''. In 1997, it was recombined as ''Praeactinocamax plenus'' by Kostak.The Paleobiology Database
''Praeactinocamax plenus'' de Blainville 1827(éteint)
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References

Coleoidea Molluscs described in 1997 {{paleo-cephalopod-stub