Catalog entries: Globorotalia (Globorotalia) merotumida
Type images: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.
Emended description:
Morphology:
Wall type:
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 |
[SCOR WG138]
Geographic distribution: Tropical to warm subtropical. [Kennett & Srinivasan 1983]
Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]
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
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:
Primary source for this page: Kennett & Srinivasan 1983, p.154
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. gsReferences:
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Globorotalia merotumida compiled by the pforams@mikrotax project team viewed: 24-5-2022
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