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Praeglobotruncana stephani


Classification: pf_mesozoic -> Hedbergellidae -> Praeglobotruncana -> Praeglobotruncana stephani
Sister taxa: P. algeriana, P. clotensis, P. compressa, P. delrioensis, P. gibba, P. hilalensis, P. inermis, P. kalaati, P. oraviensis, P. pseudoalgeriana, P. shirakinensis, P. stephani, P. sp.,

Taxonomy

Citation: Praeglobotruncana stephani (Gandolfi, 1942)
Rank: Species
Basionym: Globotruncana stephani
Synonyms: Globorotalia californica
Taxonomic discussion: Translation from Italian (Gandolfi, 1942): "It is present in the upper part of the Scaglia Bianca (it appears together with typical G. appenninica) and in all the Scaglia Rossa, it is generally frequent, but not as abundant as G. appenninica. It is not clear if it is present also in the Flysch, because the available material is scarce. In level 63, there are small forms of Globotruncana, not very well preserved, but resembling G. appenninica. Typical forms have not been found in this formation." (Gandolfi, 1942). [copied from Chronos database]

Type images:

Original description: Translation from Italian: Test small with a round outline. It is convex on the dorsal side, flat or concave on the umbilical side. The peripheral margin is rounded and slightly depressed. The chambers are depressed or angular in the middle whorl, more rounded and convex in the last whorl, rosetta-like overlapping in the inner part where they are distinctly separated and elongated in the external part like typical chambers of Globigerina. The sutures are oblique and curved in the inner whorls, tending to become radial and straight in the last whorl. In the middle whorl, following the initial globigerinid appearance, the sutures are ornamented by an alignment of pustule-like structures. Such alignment is either not-distinct or distinct when the pustules-like structures are coalescing to form a real keel. These pearl-like keels are not distinct in the external part and the last chambers are simple. In the umbilical area the chambers are well convex, the umbilicus is middle-sized, the sutures are simple, radial and deep. In thin section it is possible to see that the chambers are opened regularly in the umbilicus. The test is coarsely porous than in G. appenninica Renz and the general aspect is therefore more rugose. The chambers of the last whorl are 4 to 6.

Conchiglia piccola, rotonda al contorno, superiormente convessa, inferiormente piana o un poco concava, margine arrotondato o un po' depresso. Camere depresse o angolose nel giro mediano, più arrotondate e convesse nel giro esterno; ricoprentisi in parte a rosetta internamente, nettamente staccate e affusolate in ultimo quali tipiche camere di Globigerina. Suture un po'oblique e curve nei giri interni, con tendenza radiale e diritta nel giro esterno. Nel giro mediano dopo lo stadio globigerinoide dette suture sono orlate da una fila di tubercoli, talvolta indistinta; talvolta più netta per la fusione dei detti tubercoli tra loro, sì da formare una vera e propria carena. Queste carene perlate si fanno esternamente di nuovo indistinte sin che le ultime camere sono come si è detto semplici.

Nella parte ombelicale le camere sono ben convesse, l'ombelico è di media grandezza, le suture sòno semplici, radiali' profonde. Dalle sezioni è visibile che le camere si aprono sull'ombelico regolarmente. La conchiglia è più grossolanamente porosa che nella G. apenninica e pertanto l'aspetto è più ruvido.

Numero camere all'ultimo giro : 4-6. 

Entries in the Catalog of original descriptions: Globotruncana stephani, Globorotalia californica

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 P. appenninica zone (100.50-101.92Ma, base in Albian 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: Praeglobotruncana stephani, synonyms included - Globotruncana californica; Praeglobotruncana californica; Praeglobotruncana stephani;
  • space-time plot :: Samples map :: Parent: Praeglobotruncana

    Character matrix

    test outline:Subcircularchamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical-extraumbilical
    sp chamber shape:Petaloidcoiling axis:Moderateperiphery:Single keelaperture border:Thick lip
    umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:N/A
    spiral sutures:Raised beadedumb depth:Deepwall texture:Finely pustuloseshell porosity:Macroperforate: >2.5µm
    umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

    References:

    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 :: ::

    Gandolfi, R. (1942). Ricerche micropaleontologiche e stratigraphfiche sulla Scaglia e sul flysch Cretacici dei Dintorni di Balerna (Canton Ticino). Rivista Italiana di Paleontologia. 48: 1-160. 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 :: ::

    Leckie, M. (1984). Mid-Cretaceous planktonic foraminiferal biostratigraphy off Central Morocco, Deep Sea Drilling Project Leg 79, Sites 545 and 547. Initial Reports of the Deep Sea Drilling Project. 79: 579-620. gs :: ::

    Leckie, M. (1985). Foraminifera of the Cenomanian-Turonian boundary interval, Greenhorn Formation, Rock Canyon Antoicline, Pueblo, Colorado. In, Pratt, L. M. , Kauffman, E. G. & Zelt, F. B. (eds) Fine-grained deposits and biofacies of the Cretaeous Wesern Interior Seaway: Evidence of cyclic sedimentary processes. SEPM Field Trip Guidebook. 4: 139-149. gs :: ::

    Petrizzo, M. R. & Huber, B. T. (2006). Biostratigraphy and taxonomy of late Albian planktonic foraminifera from ODP Leg 171B (western North Atlantic Ocean). Journal of Foraminiferal Research. 36: 166-190. gs :: ::

    Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs :: ::


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    Praeglobotruncana stephani compiled by the pforams@mikrotax project team viewed: 8-7-2020

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    Short stable page link: http://mikrotax.org/pforams/index.php?id=110438 Go to Archive.is to create a permanent copy of this page - citation notes



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