Marginotruncana paraconcavata

Classification: pf_mesozoic -> Globotruncanidae -> Marginotruncana -> Marginotruncana paraconcavata
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.,


Citation: Marginotruncana paraconcavata Porthault, in Donze et al., 1970
Rank: Species
Basionym: Marginotruncana paraconcavata

Type images:

Original description: DIAGNOSE : Face dorsale plane ou legerement concave; face ventrale tres convexe. Loges tres étirées dans le sens de l'enroulement et bordées par un bourrelet sutural et périombilical sur la face ventrale. L'angle de raccordement entre les deux faces est supérieur à 60°

DESCRIPTION : Test calcaire hyalin perforé bilamellaire, g enroulement trochospiralé. Les deux faces sont fortement dissymétriques, la face dorsale étant plane ou 1égérement concave, la face ventrale fortement convexe ; l'angle de raccordement entre les deux faces oscille entre 60° et 80°.

Ouverture primaire intériomarginale ombilicale-extraombilicale. Bandeau carénal périphérique imperforé, comportant deux carénes trés proches. Les loges, au nombre de 4 g 6 au dernier tour, sont fortement étirées dans le sens de l'enroulement; sur la face ventrale, les sutures sont sigmoides et ourlées par un bourrelet sutural et périombilical se raccordant/t la caréne ventrale. Les sutures de la face spirale sont obliques et également ourlées par un bourrelet. L'ombilic relativement large est en partie recouvert par des expansions lamelleuses (<< tegilla >>) issues de la portion adombilicale des loges; il existe des ouvertures accessoires infraou intralaminales, mais non des ouvertures supplémentaires suturales.

Entries in the Catalog of original descriptions: Marginotruncana paraconcavata

Emended description: Test low trochospiral, planoconvex. Primary aperture extraumbilical-umbilical. Two closely spaced keels separeted by an imperforate peripheral band. Equatorial periphery subcircular. Chambers strongly elongated in the direction of coiling with a flat to concave (or undulated) surface on spiral side; umbilical chambers with an inflated surface and elongated in the direction of coiling; 4-6 chambers in final whorl slowly increasing in size as added. On spiral side sutures are curved, oblique and raised. On umbilical side the sutures are raised, V-shaped and sigmoid with the sutural ridge continuing around the umbilical depressions. Umbilicus wide and deep surrounded or covered by portici. [copied from Chronos database]

Geological Range:
Last occurrence (top): within D. asymetrica zone (84.19-86.71Ma, top in Santonian 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

  • 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: Marginotruncana paraconcavata, synonyms included - Globotruncana sigmocostata; Marginotruncana paraconcavata; Marginotruncana sigmoconcavata;
  • space-time plot :: Samples map :: Parent: Marginotruncana

    Character matrix

    test outline:Subcircularchamber arrangement:Trochospiraledge view:Planoconvexaperture:-
    sp chamber shape:-coiling axis:Lowperiphery:Double keelaperture border:Coalescing portici
    umb chbr shape:Trapezoidalumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
    spiral sutures:Raised beadedumb depth:Deepwall texture:Smoothshell porosity:Microperforate: <1µm
    umbilical or test sutures:Raised beadedfinal-whorl chambers:4.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable


    Donze, P., Porthalult, B., Thomel, G. & de Villoutryeys, O. (1970). Le Senonien inferieur de Puget-Theniers (Alpes-Maritimes) et sa microfaune. Geobios. 3(2): 41-106. gs :: ::

    Huber, B. T., Petrizzo, M. R., Watkins, D. K., Haynes, S. J. & MacLeod, K. G. (2017a). Correlation of Turonian continental margin and deep-sea sequences in the subtropical Indian Ocean sediments by integrated planktonic foraminiferal and calcareous nannofossil biostratigraphy. Newsletters on Stratigraphy. 50: 141-185. gs :: ::

    Robaszynski, F., Caron, M. & le Groupe de Travail Européen des Foraminifères Planctoniques (1979). Atlas des Foraminiféres Planctoniques du Crétace Moyen (Mer Boréale et Téthys). Cahiers de Micropaléontologie,. 1 & 2: 1-185. gs :: ::


    Marginotruncana paraconcavata compiled by the pforams@mikrotax project team viewed: 2-7-2020

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    Short stable page link: http://mikrotax.org/pforams/index.php?id=110335 Go to Archive.is to create a permanent copy of this page - citation notes

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