Figure 5.1. Number of reports on Cenozoic biostratigraphy in Neptune by plankton group. Reports that cover the whole or only a part of the series are included. No selection based on the detail or the quality of the reports was made. Note the overall better availability of nannofossil biostratigraphy in comparison with the other plankton groups. The anomalously low number of reports for foraminifera, diatoms and radiolarians may be in part due to the lower number of Pleistocene sections available in Neptune (Fig. 3.2). However, it likely represents also an artifact of the analysis caused by the scarcity of biostratigraphic events of these three groups calibrated for the Pleistocene.