pforams@mikrotax - Globorotalia merotumida

Globorotalia merotumida

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

K_S 1983 37-4.JPG
Lam & Leckie 2020 pl24 17-19.jpg
Lam & Leckie 2020 pl25 04 7-8.jpg

Taxonomy

Citation: Globorotalia merotumida Blow & Banner, in Banner & Blow 1965

Rank: species

Basionym: Globorotalia (Globorotalia) merotumida

Synonyms:

Globorotalia (Globorotalia) merotumida (Banner & Blow 1965) [e.g. Kennett & Srinivasan 1983]

Catalog entries: Globorotalia (Globorotalia) merotumida

Type images:

holotype: G. (Globorotalia) merotumida
holotype: G. (Globorotalia) merotumida
holotype: G. (Globorotalia) merotumida

Distinguishing features:
Parent taxon (tumida lineage): G. lenguaensis - merotumida - tumida - flexuosa lineage
This taxon: Low trochospiral, biconvex, equatorial periphery slightly lobate with distinct keel Aperture:a low arch with thick lip. Final chamber is wider than the high.

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

Emended description:

Morphology:

Test very low trochospiral, biconvex, equatorial periphery slightly lobulate, axial periphery acute with a distinct keel; 5 to 6 wedge-shaped chambers in the final whorl; chambers more inflated on umbilical side than on spiral side; spiral sutures limbate, slightly raised, thickened, curved, merging with the keel; on umbilical side gently curved to radial depressed; surface smooth, densely perforate, slightly pustulate near the aperture or umbilical side; umbilicus narrow, aperture interiomarginal, umbilical-extraumbilical, low arch with a thick lip. [Kennett & Srinivasan 1983]

Wall type:

Non-spinose; Smooth [Aze 2011]

Size:

Character matrix
test outline: Ovate chamber arrangement: Trochospiral edge view: Inequally biconvex aperture: Umbilical-extraumbilical
sp chamber shape: Crescentic coiling axis: Low periphery: Single keel aperture border: Thick lip
umb chbr shape: Subtriangular umbilicus: Narrow periph margin shape: Subangular accessory apertures: None
spiral sutures: Raised umb depth: Shallow wall texture: Smooth shell porosity: Macroperforate: >2.5µm
umbilical or test sutures: Weakly depressed final-whorl chambers: 5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution: Tropical to warm subtropical. [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): this study

Phylogenetic relations: Gr. (Gr.) merotumida differs from Gr. (Gr.) paralenguaensis in having a distinct keel and limbate sutures on the spiral side. It is distinguished from Gr. (Gr.) plesiotumida by its smaller size, slightly more convex umbilical side, less ovate equatorial profile, and the height and width of the final chamber (in merotumida the final chamber is wider than the height).
Gr. (Gr.) merotumida evolved from Gr. (Gr.) paralenguaensis in the early part of Zone N16 (Late Miocene) and is ancestral to Gr. (Gr.) plesiotumida. [Kennett & Srinivasan 1983]

Most likely ancestor: Globorotalia menardii - at confidence level 3 (out of 5). Data source: Stewart 2003 fig. 6.10; Aze et al. 2011, appendix 5. NB This differs markedly from Kennett & Srinivasan, who suggested ancestor was G. paralenguaensis.
Likely descendants: Globorotalia plesiotumida; plot with descendants

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within N18 zone (5.20-5.72Ma, top in Zanclean stage). Data source: Chaisson & Pearson (1997)
First occurrence (base): within N16 zone (8.58-9.83Ma, base in Tortonian stage). Data source: Chaisson & Pearson (1997)

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
Taxon plotted: Globorotalia merotumida, synonyms included - Globorotalia merotumida; Globorotalia tumida plesiotumida;
See also space-time plot :: Samples map :: Parent: tumida lineage

Primary source for this page: Kennett & Srinivasan 1983, p.154

References:

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

Banner, F. T. & Blow, W. H. (1965c). Two new taxa of the Globorotaliinae (Globigerinacea, foraminifera) assisting determination of the late Miocene/middle Miocene boundary. Nature. 207(5004): 1351-1354. gs

Chaisson, W. P. & Pearson, P. N. P. (1997). Planktonic foraminifer biostratigraphy at Site 925: Middle Miocene–Pleistocene. Proceedings of the Ocean Drilling Program, Scientific Results. 154: 3-31. gs V O

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

Globorotalia merotumida compiled by the pforams@mikrotax project team viewed: 24-5-2022

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Short stable page link: https://mikrotax.org/pforams/index.php?id=104113 Go to Archive.is to create a permanent copy of this page - citation notes

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test outline:	Ovate	chamber arrangement:	Trochospiral	edge view:	Inequally biconvex	aperture:	Umbilical-extraumbilical
sp chamber shape:	Crescentic	coiling axis:	Low	periphery:	Single keel	aperture border:	Thick lip
umb chbr shape:	Subtriangular	umbilicus:	Narrow	periph margin shape:	Subangular	accessory apertures:	None
spiral sutures:	Raised	umb depth:	Shallow	wall texture:	Smooth	shell porosity:	Macroperforate: >2.5µm
umbilical or test sutures:	Weakly depressed	final-whorl chambers:	5.0-6.0	N.B. These characters are used for advanced search. N/A - not applicable