Distinguishing features:
Parent taxon (Eprolithus): Moderately tall, circular to stellate, multiradiate nannoliths with 5-9 petaloid wall-cycle elements surrounding a wide central area spanned by a median diaphragm. Typically H-shaped in side view.
This taxon: Eprolithus with nine wall-elements and tall wall
Most likely ancestor:
Radiolithus orbiculatus - at confidence level 3 (out of 5). Data source: Varol 1992 (modified to include E. apertior).
| LITHS: nannolith-radiate, star-shaped, cylindrical, CA: closed, CROSS-POLARS: T-prominent, |
| Lith size: 4->8µm; Segments: 9->9; Data source notes: original description & illustrated specimens |
Geological Range:
Notes: LAD is earlier at low latitudes - in UC7 (Burnett 1998)
Last occurrence (top): in upper part of UC9a subzone (70% up, 90Ma, in Turonian stage). Data source: Burnett 1998, fig. 6.3
First occurrence (base): in upper part of BC18 zone (75% up, 119.6Ma, in Aptian stage). Data source: Bown et al. 1998, fig. 5.3
Plot of occurrence data:
Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. gs Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gs O Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O Püttmann, T., Mutterlose, J., Kaplan, U. & Scheer, U. (2019). Reworking of Cenomanian ammonites decoded by calcareous nannofossils (southern Münsterland Basin, northwest Germany). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 291(1): 1-17. gs Thomsen, E. (1987). Lower Cretaceous calcareous nannofossil biostratigraphy in the Danish Central Trough. Danmarks Geologiske Undersøgelse. 20: 1-89. gsReferences:

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Eprolithus apertior compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 7-9-2026
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