Nannotax3 - ntax_main - Braarudosphaera bigelowii Nannotax3 - ntax_main - Braarudosphaera bigelowii

Braarudosphaera bigelowii


Classification: ntax_main -> Braarudosphaerales -> Braarudosphaeraceae -> Braarudosphaera -> Braarudosphaera bigelowii
Sister taxa: B. parkeae, B. bigelowii, B. okadae, B. small form ⟩⟨ B. alta, B. insecta, B. magnei, B. pentagonica, B. perampla, B. perversus, B. sequela, B. stylifera, B. sp. ⟩⟨ B. africana, B. amputans, B. batilliformis, B. pseudobatilliformis, B. turbinea, B. wendlerae, B. sp. Cretaceous

Sub-taxa & variants (time control age-window is: 0-800Ma)
Braarudosphaera bigelowii S-cells

Braarudosphaera bigelowii - Cenozoic
Cenozoic specimens of Braarudosphaera bigelowii (sensu lato)
Braarudosphaera bigelowii - Cretaceous

Cretaceous specimens of Braarudosphaera bigelowii



Taxonomy:
Citation: Braarudosphaera bigelowii (Gran & Braarud 1935) Deflandre 1947
Taxonomic rank: species
Basionym: Pontosphaera bigelowii * Gran & Braarud 1935
Taxonomic discussion: Subdivision of modern B. bigelowii: Takano et al. (2006) and Hagino et al. (2009) showed that four different size clases of Braarudosphaera bigelowii could be recognised in modern populations from around Japan and five genotypes (based on single cell PCR amplification). These are listed below. NB Sizes quoted are side lengths of pentaliths to convert to lith diameter multiply by 1.5 to convert to coccosphere diameter multiply by 3. Genotypes I & II and IV & V formed clusters supporting the morphological separation. The degree of separation between the genotype groups suggested that the morphotypes were well-diverged species. No consistent differences between the forms were seen apart from size. This scheme was supported by observations of Konno et al. (2007) and Fernando et al. (2013). Hagino et al. 2026 formally separated the three lager size classes/genotypes as separate species. The small form was left in open nomenclature, since no genetic data was available but most likely it is another separate species.
 
 

name of Hagino et al 2009 lith diameter motile cell length genotype name in Hagino et al. 2026
Large form 11-13 µm 15-35 µm IV & V B. parkae
Intermediate form B 8-110.5µm 10-20 µm III B. bigelowii
Intermediate form A 6-7.5 µm 4-10 µm I & II B. okadae
Small form 2.2-3.8 µm no data   Small form

 


Synonyms:
Variants:sub-types within Paleocene B. bigelowii: Criscione et al. (2017) convincingly demonstated the existence of two size morphotypes in populations of B. bigelowii of mid Paleocene age (NP4-5) from Zumaia in N. Spain. Jones et al. (2021) studied the basal Danian (NP1) Braarudosphaera populations in detail, they found a similar range of specimen sizes but without convincing polymodality.

Distinguishing features:
Parent taxon (Braarudosphaera): Pentaliths approximately pentagonal, sutures go to edges of pentagon.
This taxon: Pentaliths large (8-10.5 µm across)
Motile cells 10-20 µm long
18S genotype III


Morphology:
Coccospheres are regular pentagonal dodecahedra with the plates closely butting to form a continuous cover. Liths pentagonal, surface smooth, flat or gently concave. Sutures show clockwise obliquity in distal view, running from centre to approx 3/8 of the way along side of the pentalith.
Pentalith diameter varies from about 1.5 to 7µm but in single samples all pentaliths are usually of very similar size. It is likely that several pseudo-cryptic species occur within the modern B. bigelowii (Takano et al. 2006, Hagino 2009).

Size:

Ecology & Biogeography
Neritic - predominanty observed in shelf seas, oceanic occurrences much rarer.

Biology & life-cycles
Hagino et al. (2013) showed that the alternate life-cycle stage of B. bigelowii (sensu lato) is a motile scale-bearing form previously described as Chrysochromulina parkeae Green & Leadbeater. The evidence included that they have identical 18S rDNA sequences and both have a very unusual endosymbiotic nitrogen-fixing cyanobacterium UCYN-A.

Hagino et al. (2016) showed that biomineralisation is extra-cellular, and that the pentatliths have significanly higher Mg than heterococcoliths.  

Hagino et al. (2026) showed that three separate size classes of pentalith bearing cells have well-separated by 18S DNA sequences and correlate with three separate size classes of motile cells. Hence they separated them as distinct species. 

Only recently cultured, despite numerous attempts, it is dificult to maintain and is not available currently (2019) from standard culture collections (J. Green, C. Klass, I. Probert, K. Hagino pers. coms.).

Phylogenetic relations
Molecular phylogeny (Hagino et al. 2009, 2013) proved that B. bigelowii is a haptophyte and places it either basal to the coccolithophore clade, or as a closely related clade. The biomineralisation mechanism is very different to that of coccolithophores, so it should still be regarded as a nannolith-forming species.  

Cultures: Strains of this species are maintained in culture, for details see Roscoff Culture Collection.

See also: Chrysochromulina parkeae ;

Search data:
LITHS: nannolith-radiate, pentagonal,
CSPH: equant, monomorphic, CROSS-POLARS: T-prominent,
Lith size: 2->12µm; Segments: 5->5; Coccosphere size: 4->24µm; Liths per sphere: 12->12
Data source notes: lith size (diameter) from Hagino et al. 2009; lith numbers assumed from geometry; csph size calculated
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Cenomanian Stage (93.90-100.50Ma, base in Cenomanian stage). Data source: Burnett 1998

Plot of occurrence data:

References:

Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O

Bybell, L. M. & Gartner, S. (1972). Provincialism among mid-Eocene calcareous nannofossils. Micropaleontology. 18(319-336): -. gs

Criscione, J., Bord, D., Godfery, L. & Aubry, M. -P. (2017). Inferred pseudo-cryptic speciation in the coccolithophore species Braarudosphaera bigelowii (Gran and Braarud) during the Early Paleocene (Danian). Marine Micropaleontology. 137: 1-15. gs

Deflandre, G. (1947a). Braarudosphaera nov. gen., type d'une famille nouvelle de Coccolithophorides actuels a elements composites. Comptes rendus hebdomaire de l'Académie des sciences, Paris. 225: 439-441. gs

Fernando, A. G. S., Fernandez, A. R. C. & Wiesner, M. G. (2013). Braarudosphaera bigelowii morphotypes in the surface sediments of the southwestern South China Sea. Micropaleontology. 59(6): 579-586. gs

Gran, H. H. & Braarud, T. (1935). A quantitative study of the phytoplankton in the Bay of Fundy and the Gulf of Maine (including observations on hydrography, chemistry and turbidity). Journal of the Biological Board of Canada. 1: 279-467. gs

Green, J. C. & Leadbeater, B. S. C. (1972). Chrysochromulina parkeae sp. nov. [Haptophyceae] a new species recorded from S.W. England and Norway. Journal of the Marine Biological Association of the United Kingdom. 52: 469-474. gs

Hagino, K., Takano, Y. & Horiguchi, T. (2009). Pseudo-cryptic speciation in Braarudosphaera bigelowii (Gran and Braarud) Deflandre. Marine Micropaleontology. 72: 210-221. gs

Hagino, K., Onuma, R., Kawachi, M. & Horiguchi, T. (2013). Discovery of an Endosymbiotic Nitrogen-Fixing Cyanobacterium UCYN-A in Braarudosphaera bigelowii (Prymnesiophyceae). PLoS One. 8(12): 1-11. gs

Hagino, K., Tomioka, N., Young, J. R., Takano, Y., Onuma, R. & Horiguchi, T. (2016). Extracellular calcification of Braarudosphaera bigelowii deduced from electron microscopic observations of cell surface structure and elemental composition of pentaliths. Marine Micropaleontology. 125(1): 85-94. gs

Hagino, K., et al. (2026). Taxonomic re-evaluation of the Braarudosphaera bigelowii species complex (Prymnesiophyceae). Phycologia. 1-18. gs

Jones, H. L., Scrobola, Z. & Bralower. T. J. (2021). Size and shape variation in the calcareous nannoplankton genus Braarudosphaera following the Cretaceous/Paleogene (K/Pg) mass extinction: clues as to its evolutionary success. Paleobiology. 1-24. gs

Konno, S., Harada, N., Narita, H. & Jordan, R. W. (2007). Living Braarudosphaera bigelowii (Gran & Braarud) Deflandre in the Bering Sea. Journal of Nannoplankton Research. 29(2): 78-87. gs

Lecal-Schlauder, J. (1949). Notes preliminaires sur les coccolithophorides d'Afrique duNord. Bulletin de la Société d'Histoire Naturelle de l'Afrique du Nord. 4-(5-6): 160-167. gs

Lecal-Schlauder, J. (1951). Recherches morphologiques et biologiques sur les Coccolithophorides Nord-Africains. Annales de l'Institut Océanographique, Monaco & Paris. 26: 255-362. gs

Levin, H. L. & Joerger, A. P. (1967). Calcareous nannoplankton from the Tertiary of Alabama. Micropaleontology. 13(2): 163-182. gs

Martini, E. (1961). Nannoplankton aus dem Tertiär und der obersten Kreide von SW-Frankreich. Senckenbergiana Lethaea. 42: 1-32. gs

Martini, E. (1971a). Die Typen und Typoide des Natur-Museums Senckenberg, 46): Fossiles Nannoplankton. Senckenbergiana Lethaea. 52: 115-127. gs

Stradner, H. (1960). Über Nannoplankton-Invasionen im Sarmat des Wiener Beckens. Erdoel-Zeitschrift. 76(12): 430-432. gs

Takano, Y., Hagino, K., Tanaka, Y., Horiguchi, T. & Okada, H. (2006). Phylogenetic affinities of an enigmatic nannoplankton, Braarudosphaera bigelowii based on the SSU rDNA sequences. Marine Micropaleontology. 60: 145-156. gs

Thomsen, H. A. (2016). Baltic Sea coccolithophores – an overview of insights into their taxonomy and ecology from the last 40 years. Journal of Nannoplankton Research. 36(2): 97-119. gs O

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research. S1: 1-132. gs

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Braarudosphaera bigelowii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-8-2026

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