Coccolithus pelagicus subsp. braarudii


Classification: Coccolithophores -> Coccolithales -> Coccolithaceae -> Coccolithus -> C. pelagicus group -> Coccolithus pelagicus -> Coccolithus pelagicus subsp. braarudii
Sister taxa: C. pelagicus subsp. braarudii, C. pelagicus subsp. pelagicus, C. pelagicus with bar, C. pelagicus subsp. floralis,

Distinguishing features: Larger extant subspecies, liths over 10µm long; warmer water form, 10-20°C, typically in upwellings


Taxonomy:

Citation: Coccolithus pelagicus subsp. braarudii (Gaarder 1962) Geisen et al., 2002
Rank: sub-species
Basionym: Crystallolithus braarudii Gaarder 1962
Synonyms:
Notes & discussion: We prefer to treat this form as a sub-species rather than a species, since (1) intermediate morphtypes occur in the modern ocean [my obs JRY]; (2) the genetic differentiation of the sequenced strains is relatively low in comparison to that between the Calcidiscus or Umbilicosphaera forms (Sáez et al. 2003); (3) the size bimodality often seen in modern populations does not persist in the fossil record.

Farinacci & Howe catalog pages: Crystallolithus braarudii [no catalog entry yet]

Distinguishing features: Larger extant subspecies, liths over 10µm long; warmer water form, 10-20°C, typically in upwellings


Biology & life-cycles: HOL - planar with incomplete cover of crystallites arranged in radial strings extending from a central ellipse (formerly called Crystallolithus braarudii Gaarder 1962).

Search data:
TagsLITHS: placolith, elliptical, RIM: inner-tube-broad, psh-bicyclic, CA: bar-transverse,
CSPH: spherical, monomorphic, V-UNITS: distal shield, px-tube, R-UNITS: c-str, ds-tube, prox shield, DETAILS: ca_disjunct, rim-bicyclic, isogyres oblique,
MetricsLith size: 9->15µm; Coccosphere size: 12->30µm; Liths per sphere: 6->25
Sources: csph & lith size from Gibbs et al. 2013
The morphological data given here can be used on the advanced search page. See also these notes

See also: Coccolithus pelagicus subsp. braarudii HOL ;

Geological Range:
Last occurrence (top): Extant Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: [JRY rough estimate]

Plot of occurrence data:

References:

Gaarder, K.R., (1962). Electron Microscope Studies on Holococcolithophorids. Nytt Magasin for Botanikk, 10: 35-51.

Sáez, A.G.; Probert, I.; Geisen, M.; Quinn, P.; Young, J.R. & Medlin, L.K., (2003). Pseudo-cryptic speciation in coccolithophores. Proceedings of the National Academy of Science of the United States of America, 100(12): 7163-7168.

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Coccolithus pelagicus subsp. braarudii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-10-2018

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=333Go to Archive.is to create a permanent copy of this page - citation notes
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Comments (1)

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Giulliana Villa (Parma University, Italy)
C. pelagicus braarudi is reported as temperate taxon, we found it at hight northern latitude off the Svalbard Islands. Is it possible?
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Jeremy Young (UCL, UK)
That is surprising - I would definitely expect it to be C. pelagicus ssp. pelagicus in the high Arctic, and that is what I observed there in the plankton in June 2012.
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Gonçalo Prista (Lisbon, Portugal)

Dear Professor Giulliana Villa and Professor Jeremy Young, I hope you are both fine. I have been studying C. pelagicus s.l. during my PhD and had the chance to look on a few samples from Svalbard (i believe those samples were the ones used by Katia in her PhD). I noticed and mentioned to Katia that there were quite a few coccoliths over 10 micron, which would be highly interesting to look into. I would suggest a different interpretation. Instead of placing C. braarudii in Svalbard (although it could theoretically happen, through oceanic current transportation), I would look into the morphological plasticity of C. pelagicus. C. braarudii is typically regarded between 10 and 14 micron. However there are coccoliths up to 17-18 micron and down to 8-9 micron in the Portuguese coast. My interpretation is that this is a response to variations in the upwelling regime, with larger coccoliths forming during periods with lack of nutrients and smaller coccoliths during high nutrient availability.

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Gonçalo Prista (Lisbon, Portugal)

This interpretation is in line with culture studies that show size variation as a response to nutrient availability (Daniels et al. 2014; Sheward et al. 2014, 2016) and also Gerecht et al., 2014; Gerecht et al., 2015; Šupraha et al., 2015. Maybe the larger coccoliths found in Svalbard are just morphological plasticity of C. pelagicus, responding to the environmental variations. But this would demand a morphometry study on those samples, since variations up to 12... maybe 13 micron could be due to plasticity. Coccoliths larger than that would probably not belong to pelagicus, but to braarudii. Well just to share my humble opinion.

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Jeremy Young (UK)

Goncalo

Thanks for the comment and yes I agree with you, if there are large specimens of Coccolithus off Svalbard in the plankton (as opposed to in sediments) then the most likely explanation is that they are unusually large C. pelelgicus spp. pelagicus rather than C. pelagicus ssp. braarudii. The 10µm separation work very well a lot of the time but there certainly are exceptions and complications (which is one of the reason i am reluctant to regard the two forms as species). 17-18µm is truly massive do you have images of these?

Jeremy

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