Helicosphaera compacta


Ancestry: Coccolithophores -> Zygodiscales -> Helicosphaeraceae -> Helicosphaera -> H. lophota group -> Helicosphaera compacta
Sister taxa: H. bramlettei, H. clarissima, H. compacta, H. lophota, H. neolophota, H. papillata, H. reticulata, H. robinsoniae, H. seminulum, H. wilcoxonii,

Short diagnosis: Elliptical Helicosphaera with well defined birefringent blanket in XPL and narrow central area spanned by a conjunct bar.


Taxonomy:

Citation: Helicosphaera compacta Bramlette & Wilcoxon, 1967
Rank: Species
Variants: Helicosphaera moorkensii Steurbaut, 1983 - closed central area (no pores) - NP23

Farinacci & Howe catalog pages: Helicosphaera compacta * Helicosphaera moorkensii *

Short diagnosis: Elliptical Helicosphaera with well defined birefringent blanket in XPL and narrow central area spanned by a conjunct bar.

Geological Range:
Last occurrence (top): within NP24 zone (26.84-29.62Ma, top in Chattian stage). Data source: de Kaenel & Villa, 1996
First occurrence (base): within NP16 zone (40.40-42.87Ma, base in Lutetian stage). Data source: [PRB rough estimate]

Plot of occurrence data:

References:

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

Steurbaut, E., (1983). The stratigraphic position of the Lower Oligocene Yrieu Sainds (SW France, based on calcareous nannofossils and a new Helicosphaera species Eclogae Geologicae Helvetiae, 76(2): 327-331.


Nannotax3 - Coccolithophores - Helicosphaera compacta by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-3-2017

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Simon Cole (UK)
Hi Jeremy
I've always put the LO of H. compacta intra-NP24, approximated to the top of the Early Oligocene (28.09 according to GTS2012). I believe this is where de Kaenel & Villa, 1996 observed it too in most of their sections from the Iberia Abyssal Plain. Would you consider amending the absolute age here to reflect this?
Cheers,
Simon
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Ines Galovic (Croatia)
Maybe in IAP LO of the species marks the end of E. Oligocene, but in other Oceans (ODP, IODP and in other articles) its rare appearance certainly is in the Late Oligocene i.e. NP25, like in Adriatic (Mediterranean area)-mine observation.
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