Nannotax3 - ntax_cenozoic - Cyclagelosphaera alta

Citation: Cyclagelosphaera alta Perch-Nielsen, 1979

Synonyms:

Cyclagelosphaera sp. Mai et al 1997
Cyclagelosphaera prima (Bukry 1969) Bybell & Self-Trail 1995

Taxonomic discussion: There seems to be a gradation between forms which only have a central spine and ones which also have well-developed buttresses. The type specimens of Perch-Nielsen (1979) have buttresses and these were included in the original description. Mai et al. (1997) excluded forms without buttreses and refered to these as Cyclagelosphaera sp., they are included here within C. alta. [my interpretation - JRY 2018]

Distinguishing features: Cyclagelosphaera with central-plug-forming inner tube cycle that forms a raised conical structure.

Morphology: The central spine is clearly formed from the R-units and so will show length-slow crystallographic orientation. [my interpretation - JRY 2017]

Geological Range:
Last occurrence (top): in lower part of NP3 zone (40% up, 64.2Ma, in Danian stage). Data source: Varol, 1989, fig. 12.4
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Perch-Nielsen 1985

References:

Bown, P. R., Gibbs, S. J., Sheward, R., O’Dea, S. & Higgins, D. (2014). Searching for cells: the potential of fossil coccospheres in coccolithophore research. Journal of Nannoplankton Research. 34(special): 5-21. gs V O

Bybell, L. M. & Self-Trail, J. (1995). Evolutionary, biostratigraphic and taxonomic study of calcareous nanofossils from a continuous Palaeocene-Eocene boundary section in New Jersey. U.S. Geological Survey, Professional Paper. 1554: 1-36. gs V O

Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs

Mai, H., von Salis, K., Willems, H. & Romein, A. J. T. (1997a). Fossil coccospheres from the K/T boundary section from Geulhemmerberg, The Netherlands. Micropaleontology. 43(281-302): -. gs

Mai, H., Hillebrandt-Habel, T., von Salis Perch-Nielsen, K. & Willems, H. (1998). Paleocene coccospheres from DSDP Leg 39, Site 356, Sao Paulo Plateau, S. Atlantic Ocean. Journal of Nannoplankton Research. 20(1): 21-29. gs V O

Perch-Nielsen, K. (1979a). Calcareous nannofossil zonation at the Cretaceous/Tertiary boundary in Denmark. In, Birkelund, T. & Bromley, R. G. (eds) Proceedings Cretaceous-Tertiary Boundary Events Symposium, Copenhagen, 1. Copenhagen 115-135. gs

Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs

Romein, A. J. T., Willems, H. & Mai, H. (1996). Calcareous nannoplankton of the Geulhemmerberg K/T boundary section, Maastrichtian type area, the Netherlands. Geologie en Mijnbouw. 75: 231-238. gs

Varol, O. (1989c). Palaeocene calcareous nannofossil biostratigraphy. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series. 265-310. gs V O

Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 200-224. gs

Tags	LITHS: placolith, circular, CA: ca_conjunct, process, closed, CSPH: equant, monomorphic, CROSS-POLARS: rim-unicyclic, R-prominent,
Metrics	Lith size: 5->7µm; Coccosphere size: 10->16µm; Liths per sphere: 11->13 Data source notes: morphom data from illustrated specimens

Cyclagelosphaera alta

References:

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