Globanomalina compressa


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

Taxonomy

Citation: Globanomalina compressa (Plummer 1926)
Rank: Species
Basionym: Globigerina compressa
Synonyms:
Taxonomic discussion: Plummer (1926) designated three cotypes to represent her new species and illustrated one view of each (dorsal, edge, and ventral). We have selected one of these cotypes (Plummer, 1926: fig. l i e ) as the lectotype for this species (Plate 14: Figures 1-3). The axial view of the lectotype is the view illustrated by Plummer to show the degree of compression of the test and the bluntly angular peripheral margin of the chambers of her new species. The chambers of the two paralectotypes are somewhat more inflated and the axial periphery of the test is somewhat less compressed than in the lectotype. Blow (1979) restricted his identification of G. compressa to morphotypes with compressed ogival chambers in axial view in contrast to morphotypes with an inflated rounded axial periphery, which he identified as G. cf. compressa or, if the chambers were more fully inflated, as G. planocompressa Shutskaya. Our studies separate compressa and planocompressa on the degree of compression/inflation of the chambers and the presence or absence of an imperforate peripheral margin. In the compressa -ehrenbergi-chapmani lineage an imperforate peripheral margin is a distinguishing characteristic, and the degree of compression of chambers in
the ultimate whorl may vary from slightly compressed to the compressed ogival shape. In contrast, in the planocompressa -imitata -ovalis lineage the chambers in the ultimate whorl are fully inflated and the axial periphery is perforate. [Olsson et al. 1999]

Catalog entries: Globigerina compressa;

Type images:

Short diagnosis: A small, 5 chambered smooth-walled test, with a moderately angular axial periphery, and with an imperforate peripheral margin that is moderately to strongly developed. Aperture a low, umbilical-extraumbilical arch, bordered along its entire extent by a narrow well defined lip.

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: A small, 5 chambered smooth-walled test, with a moderately angular axial periphery, and with an imperforate peripheral margin that is moderately to strongly developed. Aperture a low, umbilical-extraumbilical arch, bordered along its entire extent by a narrow well defined lip. [Olsson et al. 1999]

Character matrix

test outline:Lobatecoiling axis:Lowchamber arrangement:Trochospiralumbilicus:Wide
edge view:Equally biconvexumbilical or test sutures:Moderately depressedspiral sutures:Moderately depressedshell porosity:Finely Perforate: 1-2.5
wall texture:Smoothaperture:Umb.-extraumbilicalaperture border:Thick flangeaccessory apertures:None
periphery:N/Aumb chamber shape:Inflatedsp chbr shape:Inflatedperiph margin shape:Subangular
umb depth:Shallowdiameter mm:0.4width mm:-breadth mm:-
final-whorl chambers:4.5-5.5

Biogeography and Palaeobiology


Geographic distribution: Worldwide in low to high latitudes (Figure 17). [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: Globanomalina compressa has 8lsO and ∂13C similar to Parasubbotina varianta, S. triloculinoides, and G. ehrenbergi. The species has distinctly more positive ∂18O and more negative 8'3C than Morozovella and Praemurica. [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: This species shares morphologic similarities with G. archeocompressa in the compressed test and in the bluntly angular imperforate peripheral margin. The upper range of G. archeocompressa has not been firmly established and, consequently, its linkage with G. compressa is, at present, uncertain. We link the two species on the basis of their shared morphologic similarities (Plate 32). [Olsson et al. 1999]

Biostratigraphic distribution

Geological Range:
Notes: Zone P1c to Zone P3. [Olsson et al. 1999]
The FAD of Globanomalina compressa marks the base of zone P1c / top of P1b (Wade et al. 2011)
Last occurrence (top): within P3 zone (60.73-62.29Ma, top in Selandian stage). Data source: Olsson et al. 1999
First occurrence (base): at base of P1c subzone (0% up, 63.9Ma, in Danian 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. 40

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.


Globanomalina compressa compiled by the pforams@mikrotax project team viewed: 30-5-2017

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