Paleocene calcareous nannofossils from Tanzania (TDP sites 19, 27 and 38)

This paper documents the nannofossil record from the oldest yet recovered Paleogene sediments – Selandian to Thanetian (Zone NP5-7) – from the Tanzania Drilling Project. These sediments include frequent horizons with exceptionally preserved nannofossils and very high diversities. The observation of this high quality preservation extends the stratigraphic record of the Tanzanian Kilwa Group microfossil lagerstätte into the Paleocene. These new records include the oldest yet stratigraphic occurrences of a number of modern coccolithophore groups – the Pontosphaeraceae (Pontosphaera), Rhabdosphaeraceae (Blackites), Syracosphaeraceae (Syracosphaera), Calcidiscaceae (Calcidiscus), Gladiolithus and Solisphaera – indicating that the majority of Cenozoic coccolithophore diversity was established during the Paleocene radiation, soon after the Cretaceous-Paleogene boundary extinctions. The frequent and consistent occurrence of the Mesozoic taxon Zeugrhabdotus embergeri in Zone NP5, suggests this is a second Zeugrhabdotus survivor species. Sixteen new species are described: Braarudosphaera insecta, Bramletteius cultellus, Coccolithus subcirculus, Ericsonia aliquanta, Ericsonia media, Ericsonia monilis, Ericsonia orbis, Ellipsolithus pumex, Lanternithus unicavus, Pontosphaera veta, Solisphaera tegula, Solisphaera palmula, Toweius patellus, Toweius reticulum, Youngilithus transversipons and Youngilithus bipons. Emended taxonomic definitions are proposed for Prinsius martini and Prinsius bisulcus