Biostratigraphy and histories of upper Miocene - Pliocene Globorotalia, South Atlantic and South West Pacific

The upper Miocene-Pliocene histories of the Globorotalia miozea Plexus and G. crassaformis from the S.W. Pacific and a S. Atlantic site are assessed for their biostratigraphic utility in the mid latitudes of the Southern Hemisphere. As in the S.W. Pacific, Pliocene descendants of G. conoidea (G. pliozea, G. mons) appear in the S. Atlantic near the level at which the G. inflata lineage diverges (as G. puncticulata sphericomiozea). But there is an incomplete history of the latter at the Atlantic site examined, probably due to its northern position. Unlike S.W. Pacific sequences, S. Atlantic strata record a phyletic connection between G. juanai (= G. cibaoensis of authors) and G. crassaformis. The alignment of events in the plexus between the two regions is poor as judged by other foraminiferal datums (extinction of Globoquadrina dehiscens, entries of Globorotalia margaritae and G. crassaformis. As with the G. miozea plexus the records of these taxa probably vary according to latitudinal position.