Braarudosphaera bigelowii


Classification: Coccolithophores -> Braarudosphaerales -> Braarudosphaeraceae -> Braarudosphaera -> Braarudosphaera bigelowii
Sister taxa: B. bigelowii, B. insecta, B. magnei, B. pentagonica, B. perampla, B. perversus, B. sequela, B. stylifera, B. sp.,

Taxonomy:

Citation: Braarudosphaera bigelowii (Gran & Braarud 1935) Deflandre, 1947
Rank: Species
Basionym: Pontosphaera bigelowii Gran & Braarud 1935
Variants:
sub-types within 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) NB Sizes quoted are side lengths of pentaliths to convert to lith diameter multiply by 1.5 to convert to coccosphere diameter mutliply 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 has also been supported by observations of Konno et al. (2007) and Fernando et al. (2013). 

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.

Possible preservational variants
Synonyms:

Distinguishing features: Pentaliths pentagonal with sraight edges and flat top surface

Farinacci & Howe catalog pages: Braarudosphaera bigelowi * , Pontosphaera bigelowi * , Braarudosphaera deflandrei * , Braarudosphaera deflandrei maroccana * , Braarudosphaera irregularis * , Braarudosphaera rosa * , Braarudosphaera cheloma * , Chrysochromulina parkeae, Eodiscoaster danicus * , Micrantholithus concinnus * ,


Morphology remarks: Coccosphere 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).

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

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

Biology & life-cycles: Hagino et al. (2013) have shown that the alternate life-cycle stage is a motile scale-bearing form previously described as Chrysochromulina parkeae Green & Leadbeater. The evidence includes 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 biomineralsiation is extra-cellular, and thathe peatliths have significanly higher Mg hetrococcoliths.  

Only recently cultured, depite 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.).

Search data:
TagsLITHS: nannolith-radiate, pentagonal,
CSPH: spherical, monomorphic, T-UNITS: all,
MetricsLith size: 2->12µm; Segments: 5->5; Coccosphere size: 4->24µm; Liths per sphere: 12->12
Sources: 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

See also: Chrysochromulina parkeae;

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:

  • Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
  • Note to users in China - the diagram may not plot unless you use a VPN since I use google services on the website. If this is a problem please contact me 谢谢.
  • Taxon plotted: Braarudosphaera bigelowii, synonyms included - Braarudosphaera bigelowi; Braarudosphaera bigelowii; Braarudosphaera rosa; Micrantholithus concinnus; Pontosphaera bigelowii; space-time plot :: Samples map :: Parent: Braarudosphaera

    References:

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

    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 Hebdomadaires des Séances 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

    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

    Konno, S., Harada, N., Narita, H. & Jordan, R. W. (2007a). 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: 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

    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


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    Braarudosphaera bigelowii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-7-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=146 Go to Archive.is to create a permanent copy of this page - citation notes



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