Globigerinoides obliquus


Classification: pf_cenozoic -> Globigerinidae -> Globigerinoides -> Globigerinoides obliquus
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 obliquus Bolli, 1957
Rank: species
Basionym: Globigerinoides obliqua Bolli, 1957
Synonyms: [Spezzaferri et al. 2018]
Taxonomic discussion:

At the beginning of its range the last chamber of this species is only slightly oblique and compressed. It acquires the morphology typical of the holotype only during the Miocene starting from Zone M3 (Plate 9.6, Figs. 1-3). Kennett and Srinivasan (1983) and Chaisson and Leckie (1993) proposed G. altiaperturus as the ancestor of G. obliquus by lateral elongation of the aperture preceding the lateral compression of the chambers. This relationship is retained here.

Globigerinoides fournieri Bermúdez described from the Globigerinita dissimilis Zone is placed in synonymy with G. obliquus because its holotype (not shown) resembles the holotype of G. obliquus with the exception of the aberrant last chamber.

[Spezzaferri et al. 2018]

Catalog entries: Globigerinoides obliqua

Type images:

Distinguishing features: Obliquely compressed final chamber.

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:

Globigerinoides obliquus differs from other Globigerinoides with a similar outline (e.g., G. neoparawoodi) by having a more quadrangular profile due to the compressed oblique last chamber and generally ovate-reniform chambers in the last whorl instead of globular, and from G. bollii by its larger aperture as well as the oblique last chamber.

[Spezzaferri et al. 2018]

Wall type: Normal perforate, spinose, ruber/sacculifer-type wall. [Spezzaferri et al. 2018]

Test morphology: Low trochospiral consisting of about 3 whorls, quadrangular in outline and slightly lobate. Subspherical to ovate chambers; 4 in the last whorl gradually increasing in size. The last chamber is laterally compressed and oblique. Sutures depressed, straight to slightly curved on both sides. Umbilicus fairly open and deep. Primary aperture umbilical, medium-sized high and wide arch. One small to moderately high supplementary aperture is opposite to the primary aperture. [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype 0.5 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Lobatechamber 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:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Cosmopolitan, it is more common at middle and high latitudes. [Spezzaferri et al. 2018]

Isotope paleobiology: Chaisson and Ravelo (1997) described this species as mixed-layer dweller. Nikolaev and others (1998) identified a subsurface habitat niche from 25 to 75 m depth for the late Miocene and from 25 to 100 m depth for the Pliocene. [Spezzaferri et al. 2018]

Phylogenetic relations: Globigerinoides obliquus probably evolved from G. altiaperturus at the very end of Subzone M1b by developing lateral elongation of the aperture and compression of chambers. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerinoides altiaperturus - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig. 9; Spezzaferri et al. 2018.
Likely descendants: Globigerinoides eoconglobatus; Globigerinoides extremus;

Biostratigraphic distribution

Geological Range:
Notes: From the top of Subzone M1b (Spezzaferri, 1994) to the Pleistocene (Kennett and Srinivasan, 1983). [Spezzaferri et al. 2018]
Last occurrence (top): in mid part of PT1a subzone (46% up, 1.3Ma, 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).
First occurrence (base): within M1b subzone (21.12-22.44Ma, base in Aquitanian stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.9 p.284; Kennett & Srinivasan 1983, p.56

References:

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

Bermudez, P. J. (1961). Contribucion al estudio de las Globigerinidea de la region Caribe-Antillana (Paleoceno-Reciente). Editorial Sucre, Caracas. 1119-1393. gs

Bolli, H. M. & Saunders, J. B. (1985). Oligocene to Holocene low latitude planktic foraminifera. In, Bolli, H. M. , Saunders, J. B. & Perch-Neilsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge, UK 155-262. 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

Chaisson, W. P. & Ravelo, A. C. (1997). Changes in upper water-column structure at Site 925, late Miocene-Pleistocene: Planktonic foraminifer assemblage and isotopic evidence. Proceedings of the Ocean Drilling Program, Scientific Results. 154: 255-268. gs

Jenkins, D. G. (1971). New Zealand Cenozoic Planktonic Foraminifera. New Zealand Geological Survey, Paleontological Bulletin. 42: 1-278. 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

Nikolaev, S. D., Oskina, N. S., Blyum, N. S. & Bubenshchikova, N. V. (1998). Neogene-Quaternary variations of the ‘Pole-Equator’ temperature gradient of the surface oceanic waters in the North Atlantic and North Pacific. Global and Planetary Change. 18: 85-11. gs

Norris, R. D. (1998). Planktonic foraminifer biostratigraphy: Eastern Equatorial Atlantic. Proceedings of the Ocean Drilling Program, Scientific Results. 159: 445-479. gs

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

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs

Spezzaferri, S., Olsson, R. K. & Hemleben, C. (2018b). Taxonomy, biostratigraphy, and phylogeny of Oligocene to Lower Miocene Globigerinoides and Trilobatus. In, Wade, B. S. , Olsson, R. K. , Pearson, P. N. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 9): 269-306. gs


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Globigerinoides obliquus compiled by the pforams@mikrotax project team viewed: 21-9-2019

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