Praeorbulina circularis


Classification: pf_cenozoic -> Globigerinidae -> Praeorbulina -> Praeorbulina circularis
Sister taxa: P. circularis, P. glomerosa, P. curva, P. sp.,

Taxonomy

Citation: Praeorbulina circularis (Blow, 1956)
Rank: species
Basionym: Globigerinoides glomerosa circularis Blow 1956
Synonyms: Praeorbulina glomerosa circularis (Blow, 1956)

Catalog entries: Globigerinoides glomerosa circularis

Type images:

Distinguishing features: Test nearly spherical; last chamber enveloping >75% of the earlier test; sutural apertures circular to subcircular.

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: Subspherical to spherical

Aperture: : Numerous small apertures along basal suture [Aze 2011, based on Kennett & Srinivasan 1983]


Wall type: Spinose; Cancellate [Aze 2011]

Test morphology: Test nearly spherical with last chamber almost globular, inflated enveloping the earlier part of the test more than 75 percent; sutures depressed, surface perforate; apertures circular to subcircular, located in the sutures between the last penultimate and earlier chamber and not in the area of final chamber. [Kennett & Srinivasan 1983]

Character matrix

test outline:Circularchamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Inflatedcoiling axis:Moderateperiphery:N/Aaperture border:N/A
umb chbr shape:Inflatedumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Weakly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:1.0-3.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Tropical to temperate. [Kennett & Srinivasan 1983] Low to middle 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): Pearson et al. (1997a)

Phylogenetic relations: Pr. circularis forms part of the evolutionary lineage leading to Orbulina universa d'Orbigny and has intermediate morphology linking its immediate ancestor, Pr. glomerosa circularis is distinguished from Pr. glomerosa in having circular outline and·smaller and more numerous apertures, along the basal sutures. It differs from Orbulina suturalis in lacking areal apertures. [Kennett & Srinivasan 1983]

Most likely ancestor: Praeorbulina glomerosa - at confidence level 4 (out of 5). Data source: Kennett & Srinivasan 1983, fig. 11.
Likely descendants: Orbulina suturalis;

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): in lower part of M5b subzone (24% up, 16Ma, in Burdigalian stage). Data source: Wade et al. (2011), additional event; position within zone determined by linear interpolation from data in table 1 of Wade et al. (2011).

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.84

References:

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

Blow, W. H. (1956). Origin and evolution of the foraminiferal genus Orbulina d'Orbigny. Micropaleontology. 2(1): 57-70. gs

Fox, L. R. & Wade, B. S. (2013). Systematic taxonomy of early–middle Miocene planktonic foraminifera from the equatorial Pacific Ocean: Integrated Ocean Drilling Program, Site U1338. Journal of Foraminiferal Research. 43: 374-405. gs

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

Pearson, P. N., Shackleton, N. J. & Hall, M. A. (1997a). Stable isotopic evidence for the sympatric divergence of Globigerinoides trilobus and Orbulina universa (planktonic foraminifera). Journal of the Geological Society, London. 154: 295-302. gs


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Praeorbulina circularis compiled by the pforams@mikrotax project team viewed: 17-10-2019

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104197 Go to Archive.is to create a permanent copy of this page - citation notes



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