pforams@mikrotax - Orbulina suturalis

Citation: Orbulina suturalis Brönnimann, 1951

Synonyms:

Candorbulina universa Jedlitschka [according to Bronnimann (1951), Kennett & Srinvasan (1983)]

Taxonomic discussion: Orbulina suturalis is in our opinion to be understood as a short-lived species occurring in the middle Miocene (Wade et al. 2011) during a time when the diagnostic morphology of O. universa evolved (Pearson et al., 1997). Among living O. universa, forms similar to O. suturalis do occur but are rare and associated with an anomalously small spherical chamber relative to the enclosed “spiral” shell, or by the excentric envelopment of the sphere with respect to the spiral shell. [Brummer & Kucera 2022]

Distinguishing features:
Parent taxon (Orbulina): Spherical terminal chamber:
This taxon: final chamber not entirely enveloping earlier test

Description

Adult test almost spherical, final chamber not entirely enveloping the early part of the test. Tests show all gradations from a partly enveloped Globigerina to an almost completely enveloped one. In the adult stage, the Globigerina chambers are visible only as low, rounded projections from a general sphere; surface densely perforate; aperture areal distributed over the surface of final chamber. Supplementary apertures along sutures separating the final and earlier chambers. [Kennett & Srinivasan 1983]

Biogeography and Palaeobiology

Tropical to temperate. [Kennett & Srinivasan 1983] Low to middle latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]

[SCOR WG138]

Widely recorded as a photosymbiotic mixed-layer species but Aze et al. (2011) place it in 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 Sources cited by Aze et al. 2011 (appendix S3): D. R. M. Stewart unpublished data

O. suturalis is distinguished from Praeorbulina circularis, its immediate ancestor, by lacking the small apertures confined to the suture of the Globigerina stage and by the areal apertures over the surface. The initial evolutionary appearance of O. suturalis (Orbulina datum) has been recorded throughout the world and is taken to mark the base of the Middle Miocene. [Kennett & Srinivasan 1983]

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N21 zone (1.93-3.10Ma, top in Gelasian stage). Data source: Kennett & Srinivasan 1983
First occurrence (base): at base of M6 zone (0% up, 15.1Ma, in Langhian stage). Data source: Wade et al. (2011), zonal marker

References:

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

Brönnimann, P. (1951b). The genus Orbulina d'Orbigny in the Oligo-Miocene of Trinidad, B. W. I. Contributions from the Cushman Foundation for Foraminiferal Research. 2(4): 135+-. gs

Brummer, G-J. A. & Kucera, M. (2022). Taxonomic review of living planktonic foraminifera. Journal of Micropalaeontology. 41: 29-74. gs

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

Lam, A. & Leckie, R. M. (2020a). Late Neogene and Quaternary diversity and taxonomy of subtropical to temperate planktic foraminifera across the Kuroshio Current Extension, northwest Pacific Ocean. Micropaleontology. 66(3): 177-268. gs

Norris, R. D. (1998). Planktonic foraminifer biostratigraphy: Eastern Equatorial Atlantic. Proceedings of the Ocean Drilling Program, Scientific Results. 159: 445-479. 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 of London. 154: 295-302. gs

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:	Umbilical
sp chamber shape:	Inflated	coiling axis:	Moderate	periphery:	N/A	aperture border:	N/A
umb chbr shape:	Inflated	umbilicus:	Wide	periph margin shape:	Broadly rounded	accessory apertures:	Sutural
spiral sutures:	Flush	umb depth:	Deep	wall texture:	Cancellate	shell porosity:	Macroperforate: >2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	1.0-3.0	N.B. These characters are used for advanced search. N/A - not applicable

Orbulina suturalis

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

Comments (0)

Add Comment