Helicosphaera ampliaperta


Classification: Coccolithophores -> Zygodiscales -> Helicosphaeraceae -> Helicosphaera -> H. ampliaperta group -> Helicosphaera ampliaperta
Sister taxa: H. ampliaperta, H. scissura, H. magnifica, H. alata

Taxonomy:

Citation: Helicosphaera ampliaperta Bramlette and Wilcoxon, 1967
Rank: Species
Synonyms:
Variants:
Taxonomic discussion: The wing can be indistinct making it possible to mistake H. ampliaperta for a placolith coccolith.

Distinguishing features: Central-area open; wing merges into flange; blanket confined to central opening

Farinacci & Howe catalog pages: H. ampliaperta + * , H. porosa * , A. cucullata diademata *


Morphology: Similar to H. carteri but central-area open, and wing weaker.
The species H. porosa appears to be identical except for having a grill/peforate plate in the cetral area, it is possible that it is simply based on unusually well-preserved specimens and that a grill was originally present in all H. ampliaperta.
Holcova (2009) provides a detailed morphometric study of H. ampliaperta from the Paratethys.

Search data:
TagsLITHS: placolith, asymmetric, elliptical, CA: vacant,
CSPH: elongated, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 7->12µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of NN4 zone (100% up, 14.9Ma, in Langhian stage). Data source: zonal marker, e.g. Young 1998
First occurrence (base): near base of chron C6An.1r sub-Magnetochron (10% up, 20.4Ma, in Burdigalian stage). Data source: Raffi et al. 2006, fig. 5

Plot of occurrence data:

References:

Boesiger, T. M., de Kaenel, E., Bergen, J. A., Browning, E. & Blair, S. A. , . (2017). Oligocene to Pleistocene taxonomy and stratigraphy of the genus Helicosphaera and other placolith taxa in the circum North Atlantic Basin. Journal of Nannoplankton Research. 37(2-3): 145-175. gs V O

Bramlette, M. N. & Wilcoxon, J. A. (1967b). Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology. 5: 93-131. gs V O

de Kaenel, E. & Villa, G. (1996). Oligocene-Miocene calcareous nannofossil biostratigraphy and paleoeecology from the Iberian Abyssal Plain. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 79-145. gs V O

Haq, B. U. (1973). Evolutionary trends in the Cenozoic coccolithophore genus Helicopontosphaera. Micropaleontology. 19(1): 32-52. gs

Holcova, K. (2009). Morphometrical variability of Helicosphaera ampliaperta (calcareous nannoplankton) in the Central Paratethys: biostratigraphic and paleogeographic applications. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 253(2-3): 314-356. gs

Lehotayova, R. (1985). Helicosphaera porosa - a new species of calcareous nannoflora from Oligocene/Miocene boundary. Západné Karpaty Seria Paleontologia. 10: 103-104. gs

Olafsson, G. (1989). Quantitative calcareous nannofossil biostratigraphy of upper Oligocene to middle Miocene sediment from ODP Hole 667A and middle Miocene sediment from DSDP Site 574. Proceedings of the Ocean Drilling Program, Scientific Results. 108: 9-22. gs V O

Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs V O

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 225-265. gs V O


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Helicosphaera ampliaperta compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-11-2020

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=652 Go to Archive.is to create a permanent copy of this page - citation notes



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