Nannotax3 - ntax_mesozoic - Micula swastica

Micula swastica


Classification: ntax_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:
Parent taxon (Micula): Typically cubiform nannoliths usually formed from two superimposed and complexly-intergrown cycles of four pyramidal/blocky elements each
This taxon: Like M. staurophora but with strong chirality


Taxonomy:

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

Farinacci & Howe catalog pages: M. swastica *

Distinguishing features:
Parent taxon (Micula): Typically cubiform nannoliths usually formed from two superimposed and complexly-intergrown cycles of four pyramidal/blocky elements each
This taxon: Like M. staurophora but with strong chirality


Morphology:

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.

Size:

Search data:
LITHS: nannolith-radiate, quadrate, CA: closed,
Lith size: 4->9µm; Segments: 4->4;
Data source notes: illustrated specimens
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 Maastrichtian Stage (100% up, 66Ma, in Danian 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:

References:

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

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 V O

Manivit, H. (1989). Calcareous nannofossil biostratigraphy of Leg 108 sediments. Proceedings of the Ocean Drilling Program, Scientific Results. 108: 35-69. gs V O

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 O

Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs V O


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Micula swastica compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 30-9-2022

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Short stable page link: https://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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