Praeorbulina curva

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


Citation: Praeorbulina curva (Blow, 1956)
Rank: species
Basionym: Globigerinoides glomerosa curva Blow, 1956
Taxonomic discussion: Praeorbulina transitoria (Blow 1956)

Catalog entries: Globigerinoides glomerosa curva, Globigerinoides transitoria

Type images:

Distinguishing features: Test, subspherical to spherical, last chamber enveloping 40 to 70% of the earlier test; sutural apertures, small, few (4 to 8).

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.


Diagnostic characters: Subspherical to spherical

Aperture: : Four-eight small sutural supplementary apertures [Aze 2011, based on Kennett & Srinivasan 1983]

Wall type: Spinose; Cancellate [Aze 2011]

Test morphology: Test large, subspherical to spheri- cal, last chamber subglobular, inflated and embracing between 40 to 70 percent of the earlier test; surface coarsely perforate; sutures slightly curve to radial, depressed; primary aperture of the early portion is covered by the final embracing chamber, which has four to eight small, sutural, supplementary apertures. [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:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:2.0-3.0 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. glomerosa curva exhibits intermediate morphology between its ancestor Globigerinoides sicanus and its descendant Pr. glomerosa glomerosa. It is distinguished from Globigerinoides in having an almost spherical test and in the more numerous supplementary apertures of the last chamber. With the final chamber enveloping progressively more of the earlier portion and a concomitant increase in the number of slitlike supplementary apertures, this species changes into Pr. glomerosa glomerosa.
The evolutionary appearance of Pr. glomerosa curva marks a distinct widespread datum in the late Early Miocene. [Kennett & Srinivasan 1983]

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

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): near top of M5a subzone (91% up, 16.3Ma, 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.82


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 :: ::

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 :: ::

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


Praeorbulina curva compiled by the pforams@mikrotax project team viewed: 10-7-2020

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