Late Cretaceous (late Campanian-early Maastrichtian) radiolarian biogeography; a review

Some characteristic species of Late Cretaceous radiolarians from central Japan and the world are discussed. With respect to the relation between radiolarian distribution and latitude, Amphipyndax enesseffi Foreman, Theocampe abschnitta (Empson-Morin), Myllocercion acineton Foreman, and Dictyomitra lamellicostata Foreman were restricted to the low to intermediate latitudes. Lithomelissa heros Campbell & Clark, Lithomelissa hoplites Foreman, Theocampe altamontensis (Campbell & Clark), and Stichomitra livermorensis (Campbell & Clark) would tend to be cosmopolitan; however, only in the circum-Pacific region, they were apparently confined to northeastern Asia, northwestern North America, and the Antarctic. The existence of the distribution of the Late Cretaceous radiolarians could be explained by oceanic circulation patterns and it was important in determining Late Cretaceous provincial boundaries of radiolarians.