Globanomalina planoconica

Classification: pf_cenozoic -> Globanomalinidae -> Globanomalina -> Globanomalina planoconica
Sister taxa: G. australiformis, G. luxorensis, G. ovalis, G. imitata, G. planocompressa, G. planoconica, G. chapmani, G. pseudomenardii, G. ehrenbergi, G. compressa, G. archeocompressa, G. sp.,


Citation: Globanomalina planoconica (Subbotina 1953)
Rank: Species
Basionym: Globorotalia planoconica
Taxonomic discussion: The specimens identified as this species by Tjalsma (1977) and Huber (1991b) from the South Atlantic and southern Indian oceans, respectively, differ from the holotype (Plate 10: Figures 15-17) by having only five chambers in the ultimate whorl and by the more sharply curved sutures on the spiral side. Tjalsma reported that transitional forms between "planoconica" and G. australiformis occurred at DSDP Site 329 in the upper Paleocene and lower Eocene, suggesting that the former species was derived from the latter. It would appear that these "planoconica" morphotypes may be a different species. This possibility needs further investigation. Blow (1979) figured specimens from Zone P10 in a North Atlantic piston core that he identified as G. planoconica. These specimens have 7 to 8 chambers in the ultimate whorl and a high arched aperture that extends slightly over the axial periphery onto the spiral side. He considered these forms ancestral to Pseudohastigerina danvillensis (Howe and Wallace, 1932). Except for the greater number of chambers, Blow's
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: 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.

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.


Diagnostic characters: A small highly compressed species with a well developed, thickened, imperforate peripheral margin. The number of chambers in the ultimate whorl ranges from 5 to 6, occasionally 7. The aperture is a high umbilical-extraumbilical arch that is bordered by a thin continuous lip. The equatorial periphery is rounded in the early portions of the ultimate whorl and becomes more lobulate with the final few chambers. [Olsson et al. 1999]

Character matrix

test outline:Ovatechamber arrangement:Planispiraledge view:Planoconvexaperture:Umbilical-extraumbilical
sp chamber shape:Petaloidcoiling axis:N/Aperiphery:Imperforate bandaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Wideperiph margin shape:Subangularaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Smoothshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.5-5.5 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution: As discussed above, the taxonomy of this species needs further clarification before its distribution can be reliably plotted. At present, a middle to low latitude distribution is probable. [Olsson et al. 1999]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (1999)

Isotope paleobiology: No data available. [Olsson et al. 1999]
Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light δ13C and relatively heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: The strong imperforate peripheral margin allies this species with the chapmani lineage and suggests that it was derived from this species in upper Zone P4. [Olsson et al. 1999]

Most likely ancestor: Globanomalina chapmani - at confidence level 4 (out of 5). Data source: Olsson & Hemleben 2006, fig14.1.
Likely descendants: Planoglobanomalina pseudoalgeriana;

Biostratigraphic distribution

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. 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 :: ::


Globanomalina planoconica compiled by the pforams@mikrotax project team viewed: 5-7-2020

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