Nannoconus pseudoseptentrionalis


Classification: Mesozoic -> Braarudosphaerales -> Nannoconaceae -> Nannoconus -> Nannoconus - atypical -> Nannoconus pseudoseptentrionalis
Sister taxa: N. funiculus, N. ligius, N. magnadiscus, N. nicholasii, N. pseudoseptentrionalis, N. sabinae,

Distinguishing features: Short nannoconid with narrow canal and ragged outline in plan view. Seen mainly in plan view.


Taxonomy:

Citation: Nannoconus pseudoseptentrionalis Rutledge & Bown, 1996
Rank: Species

Farinacci & Howe catalog pages: Nannoconus pseudoseptentrionalis *

Distinguishing features: Short nannoconid with narrow canal and ragged outline in plan view. Seen mainly in plan view.


Morphology remarks: N. pseudoseptentrionalis is differentiated from other similar nannoconids by its irregular, ragged margin; this renders it similar to T. septentrionalis in XPL. These optically similar species are readily differentiated in PC (in which T. septentrionalis displays regularly-spaced wall elements), and in side view (T. septentrionalis is commonly encountered in highly distinctive side view). In end view, N. pseudoseptentrionalis lacks the weakly birefringent flanges often (but not always) seen on T. septentrionalis.

Size: 4.5-7┬Ám in diameter.

Geological Range:
Last occurrence (top): within Early Barremian Substage (129.41-130.77Ma, top in Barremian stage). Data source: Bown et al. 1998
First occurrence (base): within Early Barremian Substage (129.41-130.77Ma, base in Barremian stage). Data source: Bown et al. 1998

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Nannoconus - atypical

    References:

    Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

    Jeremiah, J. (2001). A Lower Cretaceous nannofossil zonation for the North Sea Basin. Journal of Micropalaeontology. 20: 45-80. gs

    Rutledge, D. & Bown, P. R. (1996). New names for old: taxonomic clarification of some Early Cretaceous nannofossil marker-species. Journal of Nannoplankton Research. 18: 53-59. gs


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    Nannoconus pseudoseptentrionalis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 8-12-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10766 Go to Archive.is to create a permanent copy of this page - citation notes



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