Micula adumbrata


Classification: Mesozoic -> Braarudosphaerales -> Polycyclolithaceae -> Micula -> Micula adumbrata
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 atypical structure, possible ancestral


Taxonomy:

Citation: Micula adumbrata Burnett, 1997
Rank: Species

Farinacci & Howe catalog pages: Micula adumbratus *

Distinguishing features: Like M. staurophora but with atypical structure, possible ancestral


Morphology remarks:
"In plan view in the LM, the new species appears similar to M. staurophora in one orientation but when rotated reveals a more complex morphology than the triangular blocks which comprise M. staurophora. It is difficult to discern whether the sutures between the constituent blocks of the new species cut the corners of a square (as in Micula) or the edges (as in Quadrum). In PC, there appear to be four smaller blocks situated between and/or below the main, highly birefringent ones which provide the Micula-like form." [Burnett 1997]

Evolution & Phylogeny: This new species is believed to constitute an intermediate form between Quadrum and Micula but is placed in Micula because it occurs just below the FO of M staurophora and because its interference figure is reminiscent of this species. The form is dissimilar to any species of Quadrum (compare with Varol's (1992) plates 6 and 7). [Burnett 1997]

Geological Range:
Last occurrence (top): within Coniacian Stage (86.26-89.77Ma, top in Coniacian stage). Data source: Burnett 1998
First occurrence (base): in upper part of UC9c subzone (70% up, 89.8Ma, in Turonian stage). Data source: Burnett 1998, fig 6.4

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 adumbrata, synonyms included - Micula adumbrata;
  • space-time plot :: Samples map :: Parent: Micula

    References:

    Burnett, J. A. (1997c). New species and new combinations of Cretaceous nannofossils and a note on the origin of Petrarhabdus (Deflandre) Wise & Wind. Journal of Nannoplankton Research. 19(2): 133-146. gs

    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


    nannotaxlogo400px

    Micula adumbrata compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-12-2019

    Taxon Search:
    Advanced Search

    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10674 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (0)

    No comments yet. Be the first!

    Add Comment

    * Required information
    1000
    Captcha Image
    Powered by Commentics