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Helvetoglobotruncana praehelvetica


Classification: pf_mesozoic -> Hedbergellidae -> Helvetoglobotruncana -> Helvetoglobotruncana praehelvetica
Sister taxa: H. helvetica, H. microhelvetica, H. praehelvetica, H. sp.,

Taxonomy

Citation: Helvetoglobotruncana praehelvetica (Trujillo, 1960)
Rank: Species
Basionym: Rugoglobigerina praehelvetica

Type images:

Original description: The shape of the test of R. praehelvetica is rotaloid, spiral side flattened, about 2.5 whorls constituting the spire, in transverse section the individual whorls are rounded on the spiral side and in some specimens the latter part of the ultimate whorl becomes somewhat angular, with the inner whorls occasionally raised to a common level above the outer whorls. The periphery is lobulate, and the edge is very broadly rounded. There are usually 5-6 chambers in the ultimate whorl that are quite inflated and increase rather rapidly in size as added. Sutures are calcareous, perforate, and with varying degrees of rugosity, but usually only faintly so. The umbilicus is deep and rather wide. Aperture is interiomarginal, opening into the umbilicus and often covered by a platelike extension of the final chamber. About 95% of the studied specimens coil dextrally.

Entries in the Catalog of original descriptions: Rugoglobigerina praehelvetica

Geological Range:
Last occurrence (top): within H. helvetica zone (92.56-93.52Ma, top in Turonian stage). Data source: [copied from Chronos database]
First occurrence (base): within R. cushmani zone (94.03-95.94Ma, base in Cenomanian 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: Helvetoglobotruncana praehelvetica, synonyms included - Helvetoglobotruncana praehelvetica; Praeglobotruncana praehelvetica; Whiteinella praehelvetica;
  • space-time plot :: Samples map :: Parent: Helvetoglobotruncana

    Character matrix

    test outline:Circularchamber arrangement:Trochospiraledge view:Spiroconvexaperture:Interiomarginal
    sp chamber shape:Inflatedcoiling axis:Low-moderateperiphery:N/Aaperture border:Thick lip
    umb chbr shape:Inflatedumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
    spiral sutures:Moderately depressedumb depth:Deepwall texture:shell porosity:Finely Perforate: 1-2.5µm
    umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

    References:

    Eicher, D. L. & Worstell, P. (1970). Lunatriella, a Cretaceous heterohelicid foraminifer from the western interior of the United States. Micropaleontology. 16(1): 117-121. gs :: ::

    Falzoni, F., Petrizzo, M. R., Jenkyns, H. C., Gale, A. S. & Tsikos, H. (2016). Planktonic foraminiferal biostratigraphy and assemblage composition across the Cenomanian–Turonian boundary interval at Clot Chevalier (Vocontian Basin, SE France). Cretaceous Research. 59: 69-97. 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 :: ::

    Trujillo, E. F. (1960). Upper Cretaceous foraminifera from near Redding, Shasta County, California. Journal of Paleontology. 34: 290-346. gs :: ::

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    Helvetoglobotruncana praehelvetica compiled by the pforams@mikrotax project team viewed: 5-8-2020

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