Catalog entries: Globigerinoides kennetti
Type images:Distinguishing features: Like Gs. bolli but only 3 to 3½ chambers in final whorl (vs. 4), less-embracing chambers, and more subquadrate outline
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.
Wall type: Spinose; Cancellate [Aze 2011]
Morphology: Test small, low spired, spherical to subspherical chambers, three in the final whorl; sutures distinct and incised; umbilicus small, primary aperture centered over the suture between the penultimate and antepenultimate chambers; small, supplementary apertures on the spiral :side at sutural junctions; surface heavily encrusted, but spine bases can be seen on the final chamber, indicating a spinose test (Pl. 10, Fig. 5). [Kennett & Srinivasan 1983]
Character matrix
test outline: | Ovate | chamber arrangement: | Trochospiral | edge view: | Equally biconvex | aperture: | Umbilical |
sp chamber shape: | Globular | coiling axis: | Low-moderate | periphery: | N/A | aperture border: | N/A |
umb chbr shape: | Globular | umbilicus: | Wide | periph margin shape: | Broadly rounded | accessory apertures: | Sutural |
spiral sutures: | Strongly depressed | umb depth: | Deep | wall texture: | Cancellate | shell porosity: | Macroperforate: >2.5µm |
umbilical or test sutures: | Strongly depressed | final-whorl chambers: | 3.0-3.5 | N.B. These characters are used for advanced search. N/A - not applicable |
[SCOR WG138] Close morphological similarities between Gs. kennetti and Gs. bollii suggest that they are closely related. [Kennett & Srinivasan 1983]
Geographic distribution: Low latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]
Isotope paleobiology: Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy ∂13C and relatively light ∂18O. Sources cited by Aze et al. 2011 (appendix S3): Keller (1985)
Phylogenetic relations:
Similar species: Gs. kennetti differs from Gs. bollii in having 3 to 3½ chambers instead of 4 in the final whorl, less-embracing chambers, and more subquadrate outline. [Kennett & Srinivasan 1983]
Most likely ancestor: Globigerinoides bollii - at confidence level 2 (out of 5). Data source: Kennett & Srinivasan, fig. 9, p.70; Aze et al. 2011.
Geological Range:
Notes: Zone N16 to Zone
N18 (Late Miocene).
Last occurrence (top): within N18 zone (5.20-5.72Ma, top in Zanclean stage). Data source: Kennett & Srinivasan 1983
First occurrence (base): within N16 zone (8.58-9.83Ma, base in Tortonian stage). Data source: Kennett & Srinivasan 1983
Plot of occurrence data:
Primary source for this page: Kennett & Srinivasan 1983, p.72
Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. 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. gsReferences:
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Globigerinoides kennetti compiled by the pforams@mikrotax project team viewed: 6-3-2021
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