The Morphology, Taxonomy and Biostratigraphy of Globorotalia barisanensis LeRoy, Globorotalia fohsi Cushman and Ellisor, and Related Taxa

Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale

“…There is, however, a taxonomic problem, as highlighted by Bolli and Saunders (1985), in that the morphology of the holotype of Globorotalia (Fohsella) praefohsi Blow and Banner does not seem to accord well with the concept of the taxon as originally suggested by Blow and Banner (1966). We agree with Bolli and Saunders that the praefohsi holotype can be regarded as a subjective synonym of Globorotalia lobata Bermúdez (=F.…”

“…After this more lobate morphotypes appear, as do more robust, biconvex forms. Taxonomic subdivision of this gradual chronocline into species and subspecies is inevitably subjective, and contrasting approaches were taken by Bolli (1957b), Blow (1957), Blow and Banner (1966), Olsson (1972), Stainforth et al (1975), Kennett and Srinivasan (1983), Bolli and Saunders (1985) and Berggren (1993). These various taxonomic schemes are necessarily mirrored in different approaches to the biostratigraphic subdivision of the middle Miocene based upon the taxa.…”

“…The biostratigraphic scheme used here (in slightly modified form; see the discussion below) is that first suggested by Banner and Blow (1965), Blow and Banner (1966) and reflected in the N zonal concepts of Blow (1969). This scheme capitalizes on the biostratigraphic utility of this evolutionary lineage and uses the successive first occurrences of F. peripheroacuta (a morphotype that has a distinctly pinched or acute periphery), F. 'praefohsi' (which has an incipient keel on the final one or two chambers), and F. fohsi (which has a well-developed keel on the final chamber and an incipient keel throughout the last whorl), and finally the extinction of the group as successive zonal boundaries.…”

Revision of the boundary between Lillburnian and Waiauan Stages (middle Miocene, New Zealand)

“…Highest occurrence of Fohsella peripheroronda Blow & Banner PHYLETIC STATUS: An early member (Blow & Banner 1966) of the F ohsella lineage which apparently persisted in the South Pacific temperate region after the demise of low-latitude populations (Cifelli & Scott 1986). The highest occurrence is interpreted as an extinction event.…”

“…The history of Fohsella in tropical sequences (Blow & Banner 1966) indicates that F. peripheroacuta descended from F. peripheroronda. The bioseries observed in the tropics is not seen here, and it is thought that F. peripheroacuta may be a migrant.…”