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Braunella brauni


Classification: pf_mesozoic -> Heterohelicidae -> Braunella -> Braunella brauni
Sister taxa: B. brauni, B. punctulata, B. sp.,

Taxonomy

Citation: Braunella brauni Georgescu 2007
Rank: Species
Basionym: Braunella brauni

Type images:

Original description: Braunella brauni Georgescu 2007: Test biserial throughout, chamber proliferation not observed in any of the studied specimens. Chambers are subspherical throughout, those of the earlier part of the test increase rapidly in size. Kummerform lastformed chambers are common. The rate of chamber growth is lower in the adult stage. The two rows of biserially arranged chambers are slightly divergent in some specimens. Sutures are distinct, depressed, and perpendicular to slightly oblique to the growth axis of the test. Periphery is broadly rounded, without any peripheral structures. Main aperture is in the shape of a low to, more rarely, a medium high arch at the base of the last-formed chambers. It is bordered in the central part by an imperforate band and two detached rod-like rims symmetrically arranged on the two sides of the test. The detached rims define additional apertures along the zigzag suture in the portion of the last-formed one to four chambers. Test ornamentation is irregularly reticulate, costate ornamentation being present on the last-formed one to two chambers of some specimens. Test wall is calcareous, hyaline, and finely perforate, pore diameter being in the range of 1.9-2.5 microns.

Entries in the Catalog of original descriptions: Braunella brauni;

Geological Range:
Last occurrence (top): within P. hariaensis zone (66.39-67.30Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within G. havanensis zone (74.00-75.71Ma, base in Campanian stage). Data source: [copied from Chronos database]

Plot of occurrence data:

NB Plotting of Neptune data has been disabled on the Mesozoic pages because the dataset is both small and badly affected by a few sites with erroneous age models (our obs Huber, Petrizzo, Young, Nov 2016). The data can still be viewed via the range plottertool - tools menu.

Character matrix

test outline:Subtriangularchamber arrangement:Biserialedge view:Equally biconvexaperture:Interiomarginal
umb chamber shape:Globularcoiling axis:N/Aperiphery:N/Aaperture border:Thin porticus
sp chbr shape:Globularumbilicus:N/Aperiph margin shape:Broadly roundedaccessory apertures:N/A
umbilical or test sutures:Moderately depressedumb depth:N/Awall texture:Coarsely costateshell porosity:Finely Perforate: 1-2.5µm
spiral sutures:Moderately depresseddiameter mm:0.493width mm:0.359breadth mm:0.228
final-whorl chambers:2.0-2.0

References:

Georgescu, M.D., (2007). Taxonomic re-evaluation of the Late Cretaceous serial planktonic foraminifer Gümbelina punctulata Cushman, 1938 and related species. Revista Española de Micropaleontología, 39: 1-14.


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Braunella brauni compiled by the pforams@mikrotax project team viewed: 26-9-2017

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