Micula murus


Classification: Mesozoic -> Braarudosphaerales -> Polycyclolithaceae -> Micula -> Micula murus
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: Micula in which one cycle of four elements have protrusions extending tangentially from the corners of the cube


Taxonomy:

Citation: Micula murus (Martini, 1961) Bukry, 1973
Rank: Species
Basionym: Tetralithus murus Martini, 1961
Synonyms:
Notes & discussion: Forms in which the upper cycle is greatly diminished were originally included in M. murus but are now are now placed in M. prinsii 

Farinacci & Howe catalog pages: Tetralithus murus *

Distinguishing features: Micula in which one cycle of four elements have protrusions extending tangentially from the corners of the cube


Morphology remarks: The nannolith is composed of two superimposed and complexly-intergrown cycles, one reduced in size, and each cycle twisting in opposite directions. For orientation the cycle of extended elements can be defined as at the bottom/basal. 
In plan view the elements are broadly triangular in shape, and point/twist consistently in one direction; the elements protrude significantly away from the edges of the cube. 
In side view M. murus appears thinner than in plan view, and the two superimposed cycles are of different size.

Search data:
TagsLITHS: nannolith-radiate, quadrate, star-shaped, CA: closed, T-UNITS: T-prominent,
MetricsLith size: 5->9µm; Segments: 4->4;
Sources: original description & illustrated specimens
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Important marker for the Late Maastrichtian
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): at base of UC20b subzone (0% up, 69Ma, in Maastrichtian stage). Data source: Burnett 1998 (subzonal marker)

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 murus, synonyms included - Micula mura; Micula murus; Tetralithus murus;
  • space-time plot :: Samples map :: Parent: Micula

    References:

    Bukry, D. (1973). Phytoplankton stratigraphy, Deep Sea Drilling Project Leg 20, Western Pacific Ocean. Initial Reports of the Deep Sea Drilling Project. 20: 307-317. gs :: view :: open

    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 :: view :: open

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

    Martini, E. (1961). Nannoplankton aus dem Tertiär und der obersten Kreide von SW-Frankreich. Senckenbergiana Lethaea. 42: 1-32. gs :: ::

    Müller, C. (1974). Calcareous nannoplankton, Leg 25 (Western Indian Ocean). Initial Reports of the Deep Sea Drilling Project. 25: 579-633. gs :: ::

    Perch-Nielsen, K. (1977). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs :: view :: open

    Perez-Rodriguez, I., Lees, J. A., Larasoaña, J. C., Arz, J. A. & Arenillas, I. (2012). Planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost Campanian and Maastrichtian at Zumaia, northern Spain. Cretaceous Research. 37: 100-126. gs :: ::

    Sissingh, W. (1977). Biostratigraphy of Cretaceous calcareous nannoplankton. Geologie en Mijnbouw. 65(1): 37-65. gs :: ::

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

    Varol, O. (1992). Taxonomic revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsletters on Stratigraphy. 27(93-127): -. gs :: ::

    Wise, S. W. & Wind, F. H. (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project. 36(269-491): -. gs :: view :: open


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    Micula murus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 9-7-2020

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10678 Go to Archive.is to create a permanent copy of this page - citation notes



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