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Marginotruncana pileoliformis


Classification: pf_mesozoic -> Globotruncanidae -> Marginotruncana -> Marginotruncana pileoliformis
Sister taxa: M. angusticarenata, M. caronae, M. coronata, M. desioi, M. manaurensis, M. marginata, M. paraconcavata, M. pileoliformis, M. pseudolinneiana, M. renzi, M. schneegansi, M. sigali, M. sigmoconcavata, M. sinuosa, M. tarfayaensis, M. undulata, M. sp.,

Taxonomy

Citation: Marginotruncana pileoliformis Lamolda 1977
Rank: Species
Basionym: Marginotruncana pileoliformis

Type images:

Original description: Test trochospiral; spiral side convex; ventral side flat to nearly flat. Eighteen to twenty chambers arranged in 2.5 to 3 whorls; 6 to 7 chambers in outer whorl. Equatorial periphery rounded or slightly lobulate; axial periphery sharp to sharplly rounded. Single keel on outer whorl; double keel on preceding one. Sutures on umbilical side radial to curved, raised, showing subtrapexoidal chambers;sutures on spiral side curved, raised and beaded. In younger specimens, umbilical sutures of last chambers are depressed, like those of its ancestor, Dicarinella aff. hilalensis (Barr), while those of older specimens become sigmoidal. Primary aperture interiomarginal, extraumbilical-umbilical in position. Umbilicus large, diameter approximately 1/3 of diameter of test or more. Test surface generally smooth. Wall perforate except for keel and ornamentation, which are imperforate.

Entries in the Catalog of original descriptions: Marginotruncana pileoliformis

Geological Range:
Last occurrence (top): within D. concavata zone (86.71-89.91Ma, top in Coniacian stage). Data source: [copied from Chronos database]
First occurrence (base): within H. helvetica zone (92.56-93.52Ma, base in Turonian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

Dec 2017 - Plotting of Neptune data has been re-enabled on the Mesozoic pages following revision of the age-models in Neptune. The data is, however, still very sparse for the Early Cretaceous

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Marginotruncana

    Character matrix

    test outline:chamber arrangement:Trochospiraledge view:aperture:
    sp chamber shape:coiling axis:Low-moderateperiphery:Single keelaperture border:
    umb chbr shape:umbilicus:periph margin shape:accessory apertures:
    spiral sutures:Raised beadedumb depth:wall texture:shell porosity:
    umbilical or test sutures:Raised beadedfinal-whorl chambers:6.0-7.0 N.B. These characters are used for advanced search. N/A - not applicable

    References:

    Lamolda, M. (1977). Three new species of planktonic foraminifera from the Turonian of northern Spain. Micropaleontology. 23: 470-477. gs


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    Marginotruncana pileoliformis compiled by the pforams@mikrotax project team viewed: 22-10-2019

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    Short stable page link: http://mikrotax.org/pforams/index.php?id=110336 Go to Archive.is to create a permanent copy of this page - citation notes



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