Distinguishing features:
Parent taxon (Lapideacassis): Hemispherical to cylindrical nannoliths, with walls constructed from one to several cycles of thin elements, enclosing a hollow central space; the nannolith tapers distally, and may have long apical spines or processes.
Species arranged here by number of spines.
This taxon: 1 spine; asymmetric cone
Farinacci & Howe catalog pages:
S. asymmetrica *
| LITHS: nannolith-radiate, circular, cylindrical, hollow, CA: process, CROSS-POLARS: R-prominent, |
| Lith size: 8->10µm; Segments: 8->12; Data source notes: length (excluding spines) from illustrated specimens; elem numbers from count on SEM image and extend range by +-2 |
Geological Range:
Last occurrence (top): within NP5 zone (59.54-61.51Ma, top in Selandian stage). Data source: Perch-Nielsen & Franz 1977
First occurrence (base): within Santonian Stage (83.65-85.70Ma, base in Santonian stage). Data source: Burnett 1998
Plot of occurrence data:
Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O Lees, J. A. & Bown, P. R. (2005). Upper Cretaceous calcareous nannofossil biostratigraphy, ODP Leg 198 (Shatsky Rise, Northwest Pacific Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-60. gs Perch-Nielsen, K. & Franz, H. E. (1977). Lapideacassis and Scampanella, calcareous nannofossils from the Paleocene at sites 354 and 356, DSDP Leg 39, Southern Atlantic. Initial Reports of the Deep Sea Drilling Project. 39: 849-862. gs Perez-Rodriguez, I., Lees, J. A., Larasoaña, J. C., Arz, J. A. & Arenillas, I. (2012). Planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost Campanian and Maastrichtian at Zumaia, northern Spain. Cretaceous Research. 37: 100-126. gsReferences:

![]()
![]()
![]() |
Lapideacassis asymmetrica compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 10-6-2026
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=799 Go to Archive.is to create a permanent copy of this page - citation notes |
This policy contains information about your privacy. By posting, you are declaring that you understand this policy:
This policy is subject to change at any time and without notice.
These terms and conditions contain rules about posting comments. By submitting a comment, you are declaring that you agree with these rules:
Failure to comply with these rules may result in being banned from submitting further comments.
These terms and conditions are subject to change at any time and without notice.
Comments