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Globigerinelloides barri


Classification: pf_mesozoic -> Globigerinelloididae -> Globigerinelloides -> Globigerinelloides barri
Sister taxa: G. algerianus, G. alvarezi, G. aptiensis, G. asper, G. barri, G. bentonensis, G. blowi, G. bollii, G. clavatus, G. duboisi, G. ehrenbergi, G. elongatus, G. escheri, G. ferreolensis, G. gottisi, G. impensus, G. lobatus, G. maridalensis, G. mendezensis, G. messinae, G. multispinus, G. paragottisi, G. praevolutus, G. prairiehillensis, G. pulchellus, G. saundersi, G. sigali, G. subcarinatus, G. ultramicrus,

Taxonomy

Citation: Globigerinelloides barri (Bolli, Loeblich and Tappan, 1957)
Rank: Species
Basionym: Biglobigerinella barri
Taxonomic discussion: This species shows some morphological variability mainly concerning (1) the number of chambers in the last whorl, (2) the absence/presence of one or more final twin chambers possibly resulting in (3) a double primary aperture. [copied from Chronos database]
Similar species: Globigerinelloides barri differs from Globigerinelloides algerianus on account of its (1) less numerous chambers (8 to 10 instead of 10 to 12), (2) a slightly faster growth rate, (3) reniform chambers in edge view and (4) a circular (instead of ovoid) (5) laterally inflated (instead of clearly compressed) test; moreover, Globigerinelloides barri may develop one or more final paired chambers. [copied from Chronos database]

Type images:

Original description: Biglobigerinella barri Bolli, Loeblich and Tappan 1957: Test free, planispiral, biumbilicate, nearly involute to evolute; peripheral margin somewhat lobulate; chambers ovate to nearly spherical, 8-10 in the final planispiral whorl; in some specimen a smaller low but broad final chamber may cover a double-apertured penultimate chamber or there may be a small chamber at each side of the periphery, each covering one of the lateral apertures of the penultimate chamber; sutures distinct, depressed, radial in the early portion, becoming signoid in the later stages; wall calcareous, finely perforate, surface distinctly rugose I the early portion, later chambers nearly smooth or pitted; aperture interiomarginal, in the early stage equatorial, a low arch bordered above with a narrow lip, in the later stge there is a double aperture consisting of a small extraumbilical arch at each side of the last chamber, or one to each of the final paired chambers which may extend almost into the umbilicus, each aperture bordered by a lip.

Entries in the Catalog of original descriptions: Biglobigerinella barri;

Geological Range:
Last occurrence (top): within G. algerianus zone (118.93-122.17Ma, top in Aptian stage). Data source: [copied from Chronos database]
First occurrence (base): within G. blowi zone (125.71-128.73Ma, base in Barremian 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:Subcircularcoiling axis:N/Achamber arrangement:Planispiralumbilicus:Wide
edge view:Equally biconvexumbilical or test sutures:Strongly depressedspiral sutures:Strongly depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Finely pustuloseaperture:Equatorialaperture border:Thin lipaccessory apertures:Relict
periphery:N/Aumb chamber shape:Inflatedsp chbr shape:Inflatedperiph margin shape:Broadly rounded
umb depth:Shallowdiameter mm:0.49 mmwidth mm:0.36 mmbreadth mm:
final-whorl chambers:7.0-9.0

References:

Bolli, H.M.; Loeblich, A.R., Jr. & Tappan, H., (1957). Planktonic foraminiferal families Hantkeninidae, Orbulinidae, Globorotaliidae and Globotruncanidae. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, DC, pp. 3-50.


Globigerinelloides barri compiled by the pforams@mikrotax project team viewed: 26-6-2017

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