Taxonomy:
Distinguishing features: Small (~<4 µm); sub-circular to circular; central area narrow, spanned by a plate with perforations too small to resolve in LM.
Farinacci & Howe catalog pages: T. rotundus *
Search data:Tags | LITHS: placolith, circular, elliptical, CA: ca_conjunct, grill, vacant, CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 2->4µm; |
Geological Range:
Last occurrence (top): within NP11 zone (53.70-54.17Ma, top in Ypresian stage). Data source: Perch-Nielsen 1978
First occurrence (base): within NP4 zone (61.51-63.25Ma, base in Danian stage). Data source: [PRB rough estimate]
Plot of occurrence data:
Bown, P. R. (2005d). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research. 27(1): 21-95. gs V O Bown, P. R. (2010). Calcareous nannofossils from the Paleocene/Eocene Thermal Maximum interval of southern Tanzania (TDP Site 14). Journal of Nannoplankton Research. 31(1): 11-38. gs V O Perch-Nielsen, K., Sadek, A., Barakat, M. G. & Teleb, F. (1978). Late Cretaceous and Early Tertiary Calcareous nannofossil and Planktonic foraminifera zones from Egypt. Actes du VI Colloque Africain de Micropaléontologie - Tunis 1974. Annales des Mines et de la Géologie Tunis. 28: 337-403. gs Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs Shepherd, C. L. & Kulhanek, D. K. (2016). Eocene nannofossil biostratigraphy of the mid-Waipara River section, Canterbury Basin, New Zealand. Journal of Nannoplankton Research. 26(1): 33-59. gs V O Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 200-224. gsReferences:
![]() |
Toweius rotundus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 14-4-2021
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1422 Go to Archive.is to create a permanent copy of this page - citation notes |