A taxonomic revision of Heliolithaceaeā€”Applications in resolving the problematic calcareous nannofossil biostratigraphy of the Paleocene

Andrew R. Bowman and Osman Varol


In this study, we established a taxonomic revision of Heliolithaceae, which ultimately resolved the significant taxonomic confusion of several vital species. This greatly enhanced the biostratigraphic resolution throughout the Middle-Late Paleocene. All Heliolithaceae consist of a column and discs. Because of the presence of a high column in most of the Heliolithaceae species, they naturally settle at their side or plan views randomly. Therefore, we used the mobile mounting technique to map different profiles of all Heliolithaceae species (33 species/over 1000 specimens) except two new species, Tonromeinia deflandrei and Tonromeinia noeliae. This method of analysis has forced a revision of the entire Heliolithaceae species. These revisions are essential for consistently identifying the marker species and constructing robust and reliable Paleocene zonation schemes. We have established one new order, Helitholihales and three new genera Asinithistimorfi, Caycedoae and Tonromeinia. We have also described the following 23 new species: Asinithistimorfi aubryae, Bomolithus dydimolofous, Bomolithus falklandensis, Caycedoae atlanticus, Caycedoae grandis, Caycedoae kaminadesneraidon, Caycedoae micheliorum, Caycedoae pattersonii, Caycedoae yelpaze, Heliolithus amfivolos, Heliolithus iptamenosdiskos, Heliolithus kolovos, Heliolithus magnificus, Heliolithus margarita, Heliolithus nefroeidis, Heliotrochus steurbautii, Heliotrochus typra, Tonromeinia bilenii, Tonromeinia davidii, Tonromeinia deflandrei, Tonromeinia deniseae, Tonromeinia fatmae and Tonromeinia noeliae. In addition, we have introduced four new combinations Bomolithus cantabriae, Bomolithus universus, Caycedoae conicus, and Caycedoae

Finally, we have established the stratigraphic range of the Heliolithaceae species.


Bowman, P.R., Varol, O., 2021. A Taxonomic Revision of Heliolithaceae - Applications in Resolving the Problematic Calcareous Nannofossil Biostratigraphy of the Paleocene. In: M. Montenary, M. (ed.), Calcareous nannofossil biostratigraphy of the Stratigraphy and timescales, 6, 43-223.