Variations in the numbers of species and subspecies of planktonic Foraminiferida as an indicator of New Zealand Cenozoic paleotemperatures
Abstract Studies of Recent geographic distributions of planktonic Foraminiferida have recorded only about five to six species in the subpolar seas compared about twenty-five species in the tropical oceans. A plot of the number of species and subspecies in New Zealand Cenozoic foraminiferal biostratigraphic units shows marked fluctuations in the number of species and subspecies. There is an overall correlation between the numbers of taxa and oxygen isotope temperature data. In particular, both show a low temperature in the lowermost Oligocene and a temperature peak in the Middle Miocene.