Globorotalia flexuosa


Classification: pf_cenozoic -> Globorotaliidae -> Globorotalia -> tumida lineage -> Globorotalia flexuosa
Sister taxa: G. ungulata, G. flexuosa, G. tumida, G. plesiotumida, G. merotumida,

Taxonomy

Citation: Globorotalia flexuosa (Koch 1923)
Rank: species
Basionym: Pulvinulina tumida var. flexuosa Koch 1923
Synonyms:

Catalog entries: Pulvinulina tumida flexuosa

Type images:

Distinguishing features: Like G. tumida, but anterior part of final chamber sharply bent toward the umbilicus.

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: Large, trochospiral, equatorial periphery oval to elongate, final chamber bent sharply to umbilicus, heavy keel

Aperture: Interiomarginal umbilical-extraumbilical low arch bordered by plate-like lip [Aze 2011, based on Kennett & Srinivasan 1983]


Wall type: Non-spinose; Smooth [Aze 2011]

Test morphology: Test large , trochospiral, equatorial periphery oval to elongate; axial periphery acute with a heavy keel, anterior rim of the final chamber bent sharply toward umbilicus; chambers 6 to 7 in the final whorl , with the last chamber showing extreme elongation and infolding of the anterior part toward the umbilicus; spiral sutures limbate, raised, oblique merging with the keel, umbilical sutures sinuously radial, depressed; surface smooth, densely perforate, heavily pustulate on umbil- ical shoulders; umbilicus narrow , deep ; aperture interiomarginal, umbilical-extraumbilical, a low arch bordered by a platelike lip. [Kennett & Srinivasan 1983]

Character matrix

test outline:Ovatechamber arrangement:Trochospiraledge view:Inequally biconvexaperture:Umbilical-extraumbilical
sp chamber shape:Crescenticcoiling axis:Lowperiphery:Single keelaperture border:Thin flange
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Raisedumb depth:Shallowwall texture:Smoothshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:6.0-7.0 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 3 - Open ocean thermocline. Based on light ∂13C and relatively heavy ∂18O. Sources cited by Aze et al. 2011 (appendix S3): D. R. M. Stewart unpublished data

Phylogenetic relations: Gr. (Gr.) tumida flexuosa is similar in all respects with Gr. (Gr.) tumida tumida except for the sharp bend of the anterior part of the final chamber toward the umbilicus.
Gr. (Gr.) tumida flexuosa differs from Globorotalia menardii neoflexuosa Srinivasan, Kennett, and Be in having narrower and more elliptical outline, less lobulate periphery, and a heavy keel. [Kennett & Srinivasan 1983]

Most likely ancestor: Globorotalia tumida - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig 17;Stewart 2003 fig. 6.10; Aze et al. 2011, appendix 5.

Biostratigraphic distribution

Geological Range:
Notes: Upper part of Zone N18 to N21 (latest Miocene to Late Pliocene). [Kennett & Srinivasan 1983] NB This range given by Kennett & Srinivasan is competely different to the end Pleistocene range given by Wade et al. (2011), based on Berggren et al. 1995 and ultimately Joyce et al. (1990). Bolli & Saunders (1985, p.176) note that there is a late Pleistocene interval "largely characterized by the presence of Globorotalia tumida flexuosa as has been observed in numerous sections from the low latitude Atlantic realm. However, this subspecies is apparently controlled by environment rather than time (in low latitude Pacific sections it is present for only a brief interval in the Early Pliocene. as is the case in well Bodjonegoro-1. Java).
Last occurrence (top): near top of PT1b subzone (89% up, 0.1Ma, in "Holocene" 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).
First occurrence (base): in lower part of PT1b subzone (34% up, 0.4Ma, in Ionian 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.158

References:

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

Berggren, W. A. et al. (1995a). Late Neogene chronology: New perspectives in high-resolution stratigraphy. Bulletin of the Geological Society of America. 107(11): 1272-1287. gs

Joyce, J. E., Tjalsma, L. R. C. & Prutzman, J. M. (1990). High-resolution planktic stable isotope record and spectral analysis for the last 5.35 m.y: Ocean Drilling Program site 625 Northeast Gulf of Mexico. Paleoceanography. 5(4): 507-529. gs

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

Koch, R. (1923). Die jungtertiare Foraminiferenfauna von Kabu (Res. Surbaja Java). Eclogae Geologicae Helvetiae. 18: 342-357. gs

Stewart, D. R. M. I. (2003). Evolution of Neogene globorotaliid foraminifera and Micoene climate change. In, p269 (ed.) . Earth Sciences. 1-269. gs

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. gs


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Globorotalia flexuosa compiled by the pforams@mikrotax project team viewed: 17-11-2019

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