Micula swastica


Classification: Mesozoic -> Braarudosphaerales -> Polycyclolithaceae -> Micula -> Micula swastica
Sister taxa: M. staurophora, M. adumbrata, M. concava, M. cubiformis, M. swastica, M. murus, M. prinsii, M. clypeata, M. praemurus, M. premolisilvae, M. sp.,

Distinguishing features: Like M. staurophora but with strong chirality


Taxonomy:

Citation: Micula swastica Stradner & Steinmetz, 1984
Rank: Species

Farinacci & Howe catalog pages: Micula swastica *

Distinguishing features: Like M. staurophora but with strong chirality


Morphology remarks: Micula composed of two equidimensional, superimposed and complexly-intergrown cycles. In 'normal view' the elements are broadly triangular in shape, and point/twist consistently in one direction on each surface, the sutures forming a swastica pattern; the elements may protrude slightly beyond the cube. When focussing through the structure in LM, the two cycles twist in opposite directions and, at mid-focus, the bright diagonal image that typifies Micula is seen. Side views of M. swastica are thinner than the 'normal view' and show the two superimposed cycles clearly.

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian stage). Data source: Lees & Bown 2005 - consistently present to end Cret
First occurrence (base): within Coniacian Stage (86.26-89.77Ma, base in Coniacian stage). Data source: Burnett 1998

Plot of occurrence data:

  • Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
  • Note to users in China - the diagram may not plot unless you use a VPN since I use google services on the website. If this is a problem please contact me 谢谢.
  • Taxon plotted: Micula swastica, synonyms included - Micula swastica; space-time plot :: Samples map :: Parent: Micula

    References:

    Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs

    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

    Stradner, H. & Steinmetz, J. (1984). Cretaceous calcareous nannofossils from the Angola Basin, Deep Sea Drilling Project Site 530. Initial Reports of the Deep Sea Drilling Project. 75: 565-649. gs

    Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 30(1): 39-56. gs


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    Micula swastica compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-9-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10684 Go to Archive.is to create a permanent copy of this page - citation notes



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