ABSTRACT: Atotal of 226 early Eocene to early Miocene radiolarian datum events are identified and correlated with the geochronologic time scale at SitesU1331, U1332, and U1333 in the equatorial Pacific Ocean. Seven new radiolarian subzones are proposed for the low-latitude Oligocene: Eucyrtidium diaphanes Interval Subzone (RP22b); Calocycletta (Calocycletta) robusta Interval Subzone (RP22a); Lychnocanoma apodora Interval Subzone (RP21b); Theocyrtis annosa Interval Subzone (RP21a); Eucyrtidium plesiodiaphanes Interval Subzone (RP20c); Dorcadospyris pseudopapilio Interval Subzone (RP20b); Lithocyclia angusta Interval Subzone (RP20a). These subzones significantly improve the biostratigraphic resolutionwithin theOligocene (an average of one subzone per 1.6 million years [my]).Our study corroborates previous studies,which inferred that primary Oligocene datumswere synchronous in the low-latitude Pacific. Four Eocene zones, Cryptocarpium ornatum (RP19), Calocyclas bandyca (RP18), Phormocyrtis striata striata (RP9), and Buryella clinata (RP8) are emended. Two new species/subspecies, Lychnocanoma klausi and Theocorys anaclasta clasta, are described.