2002 Volume 78 Issue 5 Pages 106-110
A specimen collected years ago by Tatsuo Muramoto from Loc. Ik 1038 in the Ikushunbetsu Valley, central Hokkaido, was temporarily labeled as Neocardioceras(?) sp., without description. It is restudied on the basis of a review of previous works. As a result, it is now recognized as representing a new species of Neocardioceras, named N. muramotoi, sp. nov. The previously known species of Neocardioceras from various regions of the world can be arranged in five biostratigraphic zones of the upper part of the Cenomanian Stage (Cretaceous) in the tripartite scale. On the ground of biostratigraphic correlation, N. muramotoi is assigned to the Zone of Metoicoceras geslinianuin-Euomphaloceras septemseriatum in the middle part of the Upper Cenomanian Substage. In this zone no species of Neocardioceras has been recognized previously.