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Globigerinelloides alvarezi


Classification: pf_mesozoic -> Globigerinelloididae -> Globigerinelloides -> Globigerinelloides alvarezi
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 alvarezi (Eternod Olvera, 1959)
Rank: Species
Basionym: Planomalina alvarezi
Synonyms: Globigerinella tururensis;
Similar species: -Distinguished from Globigerinelloides volutus (White) and G. asperus (Ehrenberg) by its greater number of chambers in the final whorl and smaller breadth to diameter ratio.
-Distinguished from Globigerinelloides impensus Sliter by lacking development of muricate keels on the perhiphery of the first chambers of the final whorl. [copied from Chronos database]

Type images:

Original description: Planomalina alvarezi Eternod Olvera 1959:

Entries in the Catalog of original descriptions: Globigerinella tururensis;
Planomalina alvarezi;


Emended description: Test small, planispiral, biumbilicate, with a moderately lobate periphery; chambers inflated, globular, slightly overlapping, increasing gradually in size, 7 to 8 in the final whorl; wall finely perforate, smooth to finely hispid; aperture a moderately high arch at the base of the final chamber with a small lip and occasionally preserved relict apertures. [copied from Chronos database]

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: [copied from Chronos database]
First occurrence (base): within Maastrichtian Stage (66.04-72.05Ma, base in Maastrichtian 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:Circularcoiling axis:N/Achamber arrangement:Planispiralumbilicus:Wide
edge view:Equally biconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Finely pustuloseaperture:Interiomarginalaperture border:Thin lipaccessory apertures:Relict
periphery:N/Aumb chamber shape:Inflatedsp chbr shape:Inflatedperiph margin shape:Moderately rounded
umb depth:Shallowdiameter mm:0.291width mm:breadth mm:
final-whorl chambers:7.0-8.0

References:

Eternod Olvera, Y., (1959). Foraminíferos del Cretácico Superior de la cuenca de Tampico-Tuxpan, Mexico. Associacion Mexicana Geólogos Petroleros, Boletin, 11: 61-134.


Globigerinelloides alvarezi compiled by the pforams@mikrotax project team viewed: 29-5-2017

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