Early Miocene (3)
Discoaster (12)
Sphenolithus (20)
Helicosphaera (14)
Neochiastozygus distentus (Bramlette & Sullivan, 1961) Perch-Nielsen, 1971
Description: Neochiastozygus with narrow central area filled with diagonal cross bars that are embedded into the rim.
Remarks:
Paleogene: Neochiastozygus distentus