pforams@mikrotax - Bolivina variabilis pforams@mikrotax - Bolivina variabilis

Bolivina variabilis

Classification: pf_cenozoic -> Benthic origins -> Bolivina -> Bolivina variabilis
Sister taxa: B. merecuanai, B. nairi, B. pseudoplicata, B. sp., B. variabilis
Sub-taxa & variants (time control age-window is: 0-800Ma)
morphotypes previously recognised as species now known to be part of the B. variabilis clade
Streptochilus globulosum
Smooth test, chambers not inflated
Streptochilus globigerum
Rugose test, with globose chambers.


Citation: Bolivina variabilis (Williamson 1858)
taxonomic rank: Species
Basionym: Textularia variabilis Williamson 1858
Taxonomic discussion: Based on molecular genetics, Darling et al. (2009) and Kucera et al. (2017) have shown that specimens from the living plankton bearing the Streptochilus morphology are conspecific with the benthic Bolivina variabilis (Williamson 1858). Kucera et al. (2017) indicated the existence of two distinct morphological types among the pelagic Bolivina, but their relationship to the two commonly recognized living species of Streptochilus (S. globulosus and S. globigerum) remains unclear and the entire group requires revision explicitly considering all relevant modern Bolivina species. The morphological and genetic variability of the tychopelagic Bolivina variabilis may justify the existence of more than one species, pending future revision. [Brummer & Kucera 2022]

As a temporary solution the two extant Streptochilus species are listed here as sub-taxa of B. variabilis [editor's comment - JRY 2022]

Catalog entries: Textularia variabilis

Type images:

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.


Character matrix
test outline:Elongatechamber arrangement:Biserialedge view:Compressedaperture:Terminal
sp chamber shape:-coiling axis:-periphery:-aperture border:-
umb chbr shape:-umbilicus:-periph margin shape:-accessory apertures:-
spiral sutures:-umb depth:-wall texture:-shell porosity:-
umbilical or test sutures:-final-whorl chambers:0-0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

Abundant and ubiquitous species occurring in outer shelf and upper slope sediments and in the plankton of tropical to temperate oceans (Darling et al., 2009; Kucera et al., 2017). [Brummer & Kucera 2022]

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source:
First occurrence (base): within Pleistocene Epoch (0.01-2.59Ma, base in Gelasian stage). Data source: I cannot find a definitive source for the range the species but records appear to be predominantly from the Quaternary [editor's comment - JRY 2022]

Plot of occurrence data:

Primary source for this page: Brummer & Kucera 2022


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

Darling, K. F., Thomas, E., Kasemann, S. A., Seears, H. A., Smart, C. W. & Wade, C. M. (2009). Surviving mass extinction by bridging the benthic/planktic divide. Proceedings of the National Academy of Sciences, USA. 106: 12629-12633. gs

Kucera, M. et al. (2017). Caught in the act: Anatomy of an ongoing benthic-planktonic transition in a marine protist. Journal of Plankton Research. 39: 436-449. gs

Meilland, J., Cornuault, P., Morard, Raphaël, Brummer, Geert-J. A. & Kucera, M. (2022). Identification guide to extant planktonic foraminifera. Part 1: Family Candeinidae and genera Berggrenia, Bolivina, Dentigloborotalia, and Neogallitellia. ICES Identification Leaflets for Plankton. 196: 1-22. gs

Williamson, W. C. (1858). On the recent foraminifera of Great Britain. The Ray Society, London. 1-107. gs O


Bolivina variabilis compiled by the pforams@mikrotax project team viewed: 18-4-2024

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