New Aptian calcareous nannofossil species from Brazil.

Abstract

The calcareous nannofossil genera Braarudosphaera and Nannoconus are significant biostratigraphic markers and palaeoecological indicators in Cretaceous marine sediments. This is particularly true for Brazilian basins where those nannofossils are used to provide regional biostratigraphic framework across the Aptian and Albian intervals. Recent calcareous nannofossil studies of Aptian sediments from the coastal basins and continental shelf offshore Brazil have recorded the occurrence of two new calcareous nannofossil species, Braarudosphaera pseudobatilliformis and Nannoconus troelsenii, which we describe herein. In addition, the description of one species, Braarudosphaera batilliformis, is emended in this work.