pforams@mikrotax - Globigerina falconensis

Citation: Globigerina falconensis Blow, 1959

Basionym: Globigerina falconensis

Synonyms:

Globorotalia (Turborotalia) palpebra Bronnimann & Resig 1971 [accorodig to Brummer & Kucera 2022]

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]

Distinguishing features:
Parent taxon (Globigerina): Low trochospirally enrolled, globose test; 3-5, globular chambers in final whorl. Aperture interiomarginal, umbilical, a high arch bordered by a thin rim-like lip or thick imperforate lip. Wall spinose; spines supported by spine collars which coalesce to form ridges.
This taxon: 4 chambers in final whorl; Umbilicus small but deep; Aperture an elongate narrow arch with prominent lip

Description

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]

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

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

Brummer, G-J. A. & Kucera, M. (2022). Taxonomic review of living planktonic foraminifera. Journal of Micropalaeontology. 41: 29-74. gs V O

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

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. 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

Siccha, M. & Kucera, M. (2017). ForCenS, a curated database of planktonic foraminifera census counts in marine surface sediment samples. Scientific Data. 4(1): 1-12. 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

test outline:	Lobate	chamber arrangement:	Trochospiral	edge view:	Equally biconvex	aperture:	Umbilical
sp chamber shape:	Globular	coiling axis:	Low-moderate	periphery:	N/A	aperture border:	Thin lip
umb chbr shape:	Globular	umbilicus:	Narrow	periph margin shape:	Broadly rounded	accessory apertures:	None
spiral sutures:	Moderately depressed	umb depth:	Deep	wall texture:	Cancellate	shell porosity:	Macroperforate: >2.5µm
umbilical or test sutures:	Strongly depressed	final-whorl chambers:	4.0-4.0	N.B. These characters are used for advanced search. N/A - not applicable

Globigerina falconensis

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

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