pforams@mikrotax - Globigerinatella insueta

Citation: Globigerinatella insueta Cushman & Stainforth 1945

Basionym: Globigerinatella insueta Cushman & Stainforth 1945

Description

Test small , subglobular, early portion trochospiral with the final chamber usually embracing; chambers of the early portion spherical , rapidly increasing in size; the large , embracing final chamber constitutes more than 70% of the test; surface smooth, in large part covered by tiny crystallites and with extremely small microperforations; aperture in the early stage interiomarginal-umbilical , in the later chambers with secondary sutural and areal apertures, surrounded by distinct lips, with small knobby pustule-like bullae sometimes covering the areal secondary apertures or crescent-shaped sutural bullae cover the secondary sutural apertures. All bullae may have infralaminal accessory apertures. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology

Tropical [Kennett & Srinivasan 1983]

Gt. insueta is distinguished from its ancestor Globigerinita glutinata by its embracing final chamber and by its secondary sutural and areal supplementary apertures. [Kennett & Srinivasan 1983]

Most likely ancestor: Globigerinita glutinata - at confidence level 3 (out of 5). Data source: Kennett & Srinivasan 1983, fig 25.

Biostratigraphic distribution

Geological Range:
Notes: The initial evolutionary appearance of Gt. insueta defines the base of Early Miocene Zone N6. Gt. insueta is a dissolution-susceptible species.
Last occurrence (top): in mid part of M6 zone (47% up, 14.7Ma, in Langhian 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): at top of M3 zone (97% up, 17.6Ma, 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).

References:

Brönnimann, P. (1950a). Occurrence and ontogeny of Globigerinatella insueta Cushman and Stainforth from the Oligocene of Trinidad, B. W. I. Contributions from the Cushman Foundation for Foraminiferal Research. 1(3&4): 80-82. gs

Cushman, J. A. & Stainforth, R. M. (1945). The foraminifera of the Cipero Marl Formation of Trinidad, British West Indies. Cushman Laboratory for Foraminiferal Research, Special Publication. 14: 1-75. 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

King, D. J., Wade, B. S., Liska, R. D. & Miller, C. G. (2020). A review of the importance of the Caribbean region in Oligo-Miocene low latitude planktonic foraminiferal biostratigraphy and the implications for modern biogeo- chronological schemes. Earth-Science Reviews. 202: 1-27. gs

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

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

test outline:	Circular	chamber arrangement:	Enveloping	edge view:	Equally biconvex	aperture:	Multiple
sp chamber shape:	Globular	coiling axis:	Low	periphery:	N/A	aperture border:	Bulla
umb chbr shape:	Globular	umbilicus:	Absent	periph margin shape:	Broadly rounded	accessory apertures:	Areal
spiral sutures:	Weakly depressed	umb depth:	N/A	wall texture:	Smooth	shell porosity:	Microperforate: <1µm
umbilical or test sutures:	Weakly depressed	final-whorl chambers:	1-1	N.B. These characters are used for advanced search. N/A - not applicable

Globigerinatella insueta

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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