specimens are similar to G. planoconica in that they possess a well-developed imperforate peripheral margin, but they differ in the apertural lip, which widens as a tooth-like projection into the umbilical area. It would appear that these morphotypes may be related to G. planoconica. The morphologic range of this species and its relationship to other species in the Eocene needs further study. [Olsson et al. 1999]
Catalog entries: Globorotalia planoconica
Type images:Distinguishing features:
Parent taxon (Globanomalina): Very low trochospiral; 5-6 chambers in final whorl; chamber-shape variable.
Aperture interiomarginal, umbilical-extraumbilical, arch with narrow lip.
Wall smooth, normally perforate, pustules in some species.
This taxon: Test small highly compressed, with well-developed, thickened, imperforate peripheral margin. Final whorl with 5-6 (rarely 7) chambers, equatorial periphery rounded becoming lobulate. Aperture high umbilical-extraumbilical arch with thin, continuous lip.
Character matrix
test outline: | Ovate | chamber arrangement: | Planispiral | edge view: | Planoconvex | aperture: | Umbilical-extraumbilical |
sp chamber shape: | Petaloid | coiling axis: | N/A | periphery: | Imperforate band | aperture border: | Thin lip |
umb chbr shape: | Subtriangular | umbilicus: | Wide | periph margin shape: | Subangular | accessory apertures: | None |
spiral sutures: | Moderately depressed | umb depth: | Deep | wall texture: | Smooth | shell porosity: | Finely Perforate: 1-2.5µm |
umbilical or test sutures: | Moderately depressed | final-whorl chambers: | 4.5-5.5 | N.B. These characters are used for advanced search. N/A - not applicable |
Geographic distribution
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)
Isotope paleobiology
Aze et al. 2011 ecogroup 3 - Open ocean thermocline; based on comparison with other species of the genus.
Phylogenetic relations
Most likely ancestor: Globanomalina chapmani - at confidence level 4 (out of 5). Data source: Olsson & Hemleben 2006, fig14.1.
Likely descendants: Planoglobanomalina pseudoalgeriana;
plot with descendants
Geological Range:
Notes: Upper Zone P4 to lower Eocene. [Olsson et al. 1999]
Last occurrence (top): in mid part of E6 zone (50% up, 50.4Ma, in Ypresian stage). Data source: Olsson & Hemleben 2006, fig14.1
First occurrence (base): in lower part of P4c subzone (20% up, 57.7Ma, in Thanetian stage). Data source: Olsson et al. 1999, fig 5a
Plot of occurrence data:
Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 44
Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs Huber, B. T. (1991c). Paleogene and Early Neogene Planktonic Foraminifer Biostratigraphy of Sites 738 and 744, Kerguelen Plateau (Southern Indian Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 119: 427-449. gs Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs Subbotina, N. N. (1953). Foraminiferes fossiles d'URSS Globigerinidae, Globorotaliidae, Hantkeninidae. Bureau de Recherches Geologiques et Minieres. 2239: 1-144. gs Tjalsma, R. C. (1977). Cenozoic Foraminifera from the South Atlantic, DSDP Leg 36. Initial Reports of the Deep Sea Drilling Project. 36: 493-518. gs References:
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Globanomalina planoconica compiled by the pforams@mikrotax project team viewed: 7-2-2025
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