Discoaster musicus


Classification: Coccolithophores -> Discoasterales -> Discoasteraceae -> Discoaster -> D. musicus group -> Discoaster musicus
Sister taxa: D. sanmiguelensis, D. ulnatus, D. patulus, D. musicus, D. carneyi, D. virginianus, D. transitus, D. micros, D. arneyi, D. premicros,

Taxonomy:

Citation: Discoaster musicus Stradner, 1959
Rank: Species
Synonyms: Discoaster sanmiguelensis Bukry, 1981
Notes & discussion: D. musicus has, like D. bollii, a well developed central area and distal knob. However, it lacks a proximal knob; the distal knob is lower than in D. bollii; and sutural rays run from it to the edge of the central area. Possibly better considered as a variety of D. exilis.

Distinguishing features: Similar to D. exilis , but with wide central area and large distal boss, prominent sutural ridges extending between the rays.

Farinacci & Howe catalog pages: Discoaster musicus * , Discoaster sanmiguelensis *


Morphology remarks: 6-rayed discoaster with bifurcate rays, similar to D. exilis in having complanate rays with triangular tips, but with wide central area and large distal boss with prominent sutural ridges extending between the rays.

Search data:
TagsLITHS: nannolith-radiate, star-shaped, RIM: tips-bifurcate, free-rays-short, PROCESS: boss, boss-distal, distal-star,
CSPH: not known, V-UNITS: all, R-UNITS: none, DETAILS: 1ou,
MetricsLith size: 9->15µm; Segments: 6->6;
Sources: size from ODs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Confined to NN5 in the Mediterranean (Theodoridis 1984) but ranges into NN6 in the East Pacific (Bukry 1981), distribution probably patchy
Last occurrence (top): within NN6 zone (11.90-13.53Ma, top in Sarmatian stage). Data source: Young 1998
First occurrence (base): within NN5 zone (13.53-14.91Ma, base in Badenian stage). Data source: Young 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: Discoaster musicus, synonyms included - Discoaster musicus; Discoaster sanmiguelensis; space-time plot :: Samples map :: Parent: D. musicus group

    References:

    Bukry, D. (1981b). Pacific coast coccolith stratigraphy between Point Conception and Cabo Orientes, Deep Sea Drilling Project Leg 63. Initial Reports of the Deep Sea Drilling Project. 63: 445-471. gs

    de Kaenel, E. & Villa, G. (1996). Oligocene-Miocene calcareous nannofossil biostratigraphy and paleoeecology from the Iberian Abyssal Plain. Proceedings of the Ocean Drilling Program. Scientific Results. 149: 79-145. gs

    de Kaenel, E., Bergen, J. A., Browning, E., Blair, S. A. & Boesiger, T. M. (2017). Uppermost Oligocene to Middle Miocene Discoaster and Catinaster taxonomy and stratigraphy in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 215-244. gs

    Stradner, H. (1959b). First report on the discoasters of the Tertiary of Austria and their stratigraphic use. Proceedings of the Fifth World Petroleum Congress. 1: 1081-1095. gs

    Stradner, H., Aubry, M. -P. & Bonnemaison, M. (2010). Calcareous nannofossil type specimens in the collection of the Geological Survey of Austria: A taxonomic and stratigraphic update. Jahrbuch der Geologischen Bundesanstalt. 150(1-2): 9-84. gs

    Theodoridis, S. (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32: 1-271. gs

    Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 225-265. gs


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    Discoaster musicus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-8-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=486 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (2)

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    Richard Denne (Marathon Oil, Houston, US)
    Discoaster musicus large of Denne
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    Mike Styzen (Noble Energy, US)
    Mike Styzen - In the GOM D. sanmiguelensis is used as a marker and is distinguished as being somewhat smaller than D. musicus with shorter rays. One might argue that what we're using is just a specific morphotype of D. musicus, but in any case it's a distinction that has stratigraphic function. Richard Howe was kind enough to let me use an image of our D. sanmiguelensis concept
    Gravatar
    Jeremy Young (NHM, UK)

    this raises plenty of issues

    1. Commenting on 'missing taxa'. This is potentially a really valuable funtion of Nannotax, i.e. to get us discussing the less universally understood species concepts. I think it is best done at the place where the taxon is missing from - (so I have copied the comment to the D. musicus page).

    2. Posting images - as you found out drag & drop works from external websites, which makes for a great way to rapidly discuss taxa. For a more permanent upload, or for image which are not on an external website use Add Image to put the image in a gallery then drag and drop from there. I've reposted theimage to the Disocaster gallery. [NB Image upload by users is not possible with the current software version but I will rapidly upload any images sent to me - JRY March 2014]

    3. Morphotypes and species - if all species were nice and discrete then biostrat would be boringly easy. They aren't though: we know from modern assemblages than biologically separate species can produce very similar coccoliths, and biostrat experience tells us that some arbitrary distinctions are useful. The problem is to keep track of the concepts people are using when things get arbitrary, which is one reason why we have the site.

    4. musicus vs sanmiguelensis - what is the difference in size and range; (and is there a reason for applying the name sanmiguelensis to the smaller form)?

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