Globigerinoides diminutus


Classification: pf_cenozoic -> Globigerinidae -> Globigerinoides -> Globigerinoides diminutus
Sister taxa: G. elongatus, G. extremus, G. conglobatus, G. eoconglobatus, G. obliquus, G. altiaperturus, G. joli, G. neoparawoodi, G. kennetti, G. bollii, G. italicus, G. ruber, G. mitra, G. seigliei, G. subquadratus, G. diminutus, G. bulloideus, G. sp.,

Taxonomy

Citation: Globigerinoides diminutus Bolli, 1957
Rank: species
Basionym: Globigerinoides diminutus

Catalog entries: Globigerinoides diminuta

Type images:

Distinguishing features: Like G. subquadratus but very small, compact test. Apertures almost curcular, symmetrically above sutures.

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters: Small, trochospiral, equatorial periphery subquadrate

Aperture: Primary aperture interiomarginal umbilical small circular symmetrical arch. Supplementary sutural apertures on spiral side [Aze 2011, based on Kennett & Srinivasan 1983]


Wall type: Spinose; Cancellate [Aze 2011]

Test morphology: Test small, trochospiral, equatorial periphery subquadrate, chambers spherical in early stages, later becoming laterally compressed ; three chambers in the final whorl , increasing moderately in size; sutures on both spiral and umbilical side radial and depressed; surface distinctly cancellate; umbilicus small, primary aperture interiomarginal , umbilical small, almost circular symmetrically above the suture line of the two earlier chambers ; supplementary sutural apertures, generally two situated over the sutures of earlier chambers. [Kennett & Srinivasan 1983]

Character matrix

test outline:Subcircularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:N/A
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.0-3.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Tropical [Kennett & Srinivasan 1983] Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]

[SCOR WG138]


Isotope paleobiology: Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy ∂13C and relatively light ∂18O. Sources cited by Aze et al. 2011 (appendix S3): Keller (1985)

Phylogenetic relations: The position of the apertures symmetrically above the sutures between two earlier chambers, the subquadrate shape of the test, and the cancellate surface in both the Gs. diminutus and Gs. subquadratus suggest a close phylogenetic relationship between these two forms. Gs. diminutus is distinguished from Gs. subquadratus by its very small size and more compact test.
Possibly Gs. diminutus represents a tropical variant of Gs. subquadratus. [Kennett & Srinivasan 1983]

Most likely ancestor: Globigerinoides subquadratus - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig. 10.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N9 zone (14.24-15.10Ma, top in Langhian stage). Data source: Kennett & Srinivasan 1983
First occurrence (base): within N7 zone (16.38-17.54Ma, base in Burdigalian stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.74

References:

Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs

Bolli, H. M. (1957b). Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli & E. Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 97-123. gs

Keller, G. (1985). Depth stratification of planktonic foraminifers in the Miocene Ocean. In, Kennett, J. P. (ed.) The Miocene Ocean: Paleoceanography and Biogeography. GSA Memoir. 163: 1-337. gs

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs


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Globigerinoides diminutus compiled by the pforams@mikrotax project team viewed: 24-10-2019

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