Globanomalina pseudomenardii


Classification: pf_cenozoic -> smooth non-spinose -> Hedbergellidae -> Globanomalina -> Globanomalina pseudomenardii
Sister taxa: G. archeocompressa, G. australiformis, G. chapmani, G. compressa, G. ehrenbergi, G. imitata, G. luxorensis, G. ovalis, G. planocompressa, G. planoconica, G. pseudomenardii, G. sp.,

Taxonomy

Citation: Globanomalina pseudomenardii (Bolli 1957)
Rank: Species
Basionym: Globorotalia pseudomenardii
Synonyms:
Taxonomic discussion: There is considerable variation in the shape of the equatorial periphery, which varies from fairly smooth to strongly lobulate, depending on the rate of size increase or decrease of the final few chambers in the ultimate whorl. [Olsson et al. 1999]

Catalog entries: Globorotalia pseudomenardii;

Type images:

Short diagnosis: The distinct keel, the sharply-angled axial periphery, spiroconvex test, and narrow umbilicus are distinguishing features. The number of chambers in the ultimate whorl is consistently 5, but rarely a 6 chambered form is observed.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Diagnostic characters: The distinct keel, the sharply-angled axial periphery, spiroconvex test, and narrow umbilicus are distinguishing features. The number of chambers in the ultimate whorl is consistently 5, but rarely a 6 chambered form is observed. [Olsson et al. 1999]

Character matrix

test outline:Elongatecoiling axis:Very lowchamber arrangement:Trochospiralumbilicus:Wide
edge view:Inequally biconvexumbilical or test sutures:Moderately depressedspiral sutures:Weakly depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Smoothaperture:Umb.-extraumbilicalaperture border:Thin lipaccessory apertures:None
periphery:Single keelumb chamber shape:Subtriangularsp chbr shape:Petaloidperiph margin shape:Subangular
umb depth:Shallowdiameter mm:0.34width mm:-breadth mm:-
final-whorl chambers:5.0-6.0

Biogeography and Palaeobiology


Geographic distribution: Widely reported in the low to middle latitudes (Figure 18). [Olsson et al. 1999]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)

Isotope paleobiology: Globanomalina pseudomenardii has ∂18O and ∂13C similar to Parasubbotina varianta and S. velascoensis. The species has distinctly more positive ∂18O and more negative ∂13C than Morozovella, Acarinina, and Igorina. [Olsson et al. 1999]
Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light δ13C and relatively heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): Olsson et al. (1999)

Phylogenetic relations: There is general agreement among workers that G. pseudomenardii originated from G. ehrenbergi (= G. haunsbergensis Gohrbandt) by an increase in the test size and the development of a peripheral keel. The species becomes extinct at the top of Zone P4. [Olsson et al. 1999]

Biostratigraphic distribution

Geological Range:
Notes: Zone P4. [Olsson et al. 1999]
The FAD of Globanomalina pseudomenardii marks the base of zone P4a / top of P3b (Wade et al. 2011)
Last occurrence (top): at top of P4 zone (100% up, 57.1Ma, in Thanetian stage). Data source: zonal marker (Wade et al. 2011)
First occurrence (base): at base of P4 zone (0% up, 60.7Ma, in Selandian stage). Data source: zonal marker (Wade et al. 2011)

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 45

References:

Olsson, R.K.; Hemleben, C.; Berggren, W.A. & Huber, B.T., (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Contributions to Paleobiology. Smithsonian Institution Press, Washington, DC, 1-252 pp.

Wade, B.S.; Pearson, P.N.; Berggren, W.A. & Pälike, H., (2011). Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth-Science Reviews, 104: 111-142.


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Globanomalina pseudomenardii compiled by the pforams@mikrotax project team viewed: 27-7-2017

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