Globigerina falconensis


Classification: pf_cenozoic -> Globigerinidae -> Globigerina -> Globigerina falconensis
Sister taxa: G. bulloides, G. falconensis, G. umbilicata, G. archaeobulloides, G. officinalis, G. sp.,

Taxonomy

Citation: Globigerina falconensis Blow, 1959
Rank: species
Basionym: Globigerina falconensis
Variants:
  • G. antarctica Keany and Kennett, 1972 may be a Quaternary geographic subspecies of G. falconensis (thin-walled, higher-arched aperture) whose range is restricted to the Subantarctic.
Taxonomic discussion:

G. falconensis closely resembles G. praebulloides Blow and G. bulloides d'Orbigny but differs in having the final chamber with well-developed imperforate lip. Earlier nonbiometric studies suggested that G. falconensis and G. bulloides may represent subspecies or phenotypic variants of a single species; however, biometric analysis by Malmgren and Kennett (1977) revealed that these two forms tend to react as different species in all essential foraminiferal parameters, and therefore the taxonomic distinction between these forms should be retained. This species appears to have evolved from G. praebulloides during the Early Miocene. [Kennett & Srinivasan 1983]

Catalog entries: Globigerina falconensis, Globigerina antarctica

Type images:

Distinguishing features: 4 chambers in final whorl; Umbilicus small but deep; Aperture an elongate narrow arch with prominent 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.

Description


Diagnostic characters: Low trochospiral, slightly compressed, spherical chambers

Aperture: Interiomarginal umbilical elongate narrow arch [Aze 2011, based on Kennett & Srinivasan 1983]

Coiling direction (in extant population): mixed


Wall type: Spinose; Hispid [Aze 2011]

Test morphology: Test low trochospiral, slightly compressed, with four chambers in the final whorl; chambers spherical, increasing slowly in size as added; the last chamber typically smaller than the penultimate; sutures on both sides radial, depressed; surface with small, regularly distributed pores and thin, simple spines. Umbilicus small but deep, partly covered by a strongly developed lip of the final chamber. Aperture an elongate narrow arch, interiomarginal, umbilical. [Kennett & Srinivasan 1983]

Size: >150µm

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:Thin lip
umb chbr shape:Globularumbilicus:Narrowperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: High latitudes [Aze et al. 2011, based on Kennett & Srinivasan (1983)]

In modern oceans a common, temperate water, species [SCOR WG138]


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 Cited sources (Aze et al. 2011 appendix S3): this study

Phylogenetic relations: Molecular Genotypes recognised (data from PFR2 database, June 2017), one genotype only from 8 sequences. References: Ujiié & Lipps 2009; Stewart et al. 2001.

Most likely ancestor: Globigerina bulloides - at confidence level 1 (out of 5). Data source: Kennett & Srinivasan 1983 indicate G. bulloides and G. praebulloides as possible ancestors, G. praebulloides is not now recognised (see Spezzaferri et al. 2018) so G. bulloides seems the most likely ancestor [my interpretation - JRY 2018].

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant Data source: present in the plankton (SCOR WG138)
First occurrence (base): within N7 zone (16.38-17.54Ma, base in Burdigalian stage). Data source: Kennett & Srinivasan 1983

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.40

References:

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

Blow, W. H. (1959). Age, correlation, and biostratigraphy of the upper Tocuyo (San Lorenzo) and Pozon Formations, eastern Falcon, Venezuela. Bulletins of American Paleontology. 39(178): 67-251. gs

Keany, J. & Kennett, J. P. (1972). Pliocene-early Pleistocene paleoclimatic history recorded in Antarctic-subantarctic deep-sea cores,. Deep Sea Research. 19(8): 529-548. gs

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs

Malmgren, B. A. & Kennett, J. P. (1977). Biometric differentiation between Recent Globigerina bulloides and Globigerina falconensis in the southern Indian Ocean,. Journal of Foraminiferal Research. 7(2): 130-148. gs

Stewart, I. A., Darling, K. F., Kroon, D., Wade, C. M. & Troelstra, S. R. (2001). Genotypic variability in subarctic Atlantic planktic foraminifera. Marine Micropaleontology. 43: 143-153. gs

Ujiié, Y. & Lipps, J. H. (2009). Cryptic diversity in planktonic foraminifera in the northwest Pacific ocean. Journal of Foraminiferal Research. 39: 145-154. gs


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Globigerina falconensis compiled by the pforams@mikrotax project team viewed: 18-10-2019

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