The genus Anthocyrtidium (Radiolaria) from the tropical late Neogene of the Indian and Pacific oceans

Extensive study of the radiolarian genus Anthocyrtidium Haeckel in Neogene (< 8 Ma) sediment from the tropical Indian and Pacific Oceans permits description of the detailed morphologies of ten species (two new) along with their geographic and stratigraphic ranges. Phylogenetic lineages may be proposed in some cases, but in general our studies have not revealed clear evolutionary trends. However, eight stratigraphically useful and easily recognizable Neogene datum levels based on Anthocyrtidium can be identified and paleomagnetically dated.