Sphenolithus peartiae


Classification: Coccolithophores -> Discoasterales -> Sphenolithaceae -> Sphenolithus -> S. predistentus group -> Sphenolithus peartiae
Sister taxa: S. ciperoensis, S. distentus, S. predistentus, S. patifunditus, S. bulbulus, S. tawfikii, S. celsus, S. peartiae, S. akropodus, S. tribulosus, S. directus, S. avis, S. umbrellus, S. triangularis, S. intercalaris, S. obtusus,

Taxonomy:

Citation: Sphenolithus peartiae Bown & Dunkley Jones, 2012
Rank: Species
Notes & discussion: Like S. predistentus but with a basal birefringent structure between the feet, and similar to S. ciperoensis but with lower feet that do not insert into the spine and greater base height to width ratio. Similar basal W/H ratio as S. distentus (1.74-1.95) but has basal birefringent structure. [Bown & Dunkley Jones 2012]

According to Bergen et al. (2017) "

A lot of the variation in the extinction lines of the S. distentus - S. predistentus plexus is taken up by S. peartiae. Sphenolithus predistentus is reserved herein for specimens with horizontal extinction lines and rounded to narrow wedge-shpaed "feet" (extintion angle <20°) and lower bases (Sphenolithus distentus is reserved herein for specimens with diagonal extinction lines symmetric to the horizontal, which touch when specimens are oriented 45° to the polarizer. [i.e. they use S. peartiae as a catch-all category after excluding rigorously identified S. distentus and S. predistentus morphotpyes]

Distinguishing features: Small to medium sized sphenolith with low base that meets the spine along horizontal or near horizontal sutures but when at 45° to polarising direction a birefringent structure passes between the basal ‘feet’.

Farinacci & Howe catalog pages: Sphenolithus peartiae + *


Morphology remarks: Small to medium sized sphenolith with low base that meets the spine along horizontal or near horizontal sutures but when at 45° to polarising direction a birefringent structure passes between the basal ‘feet’.

Size: Holotype H = 6.20µm, W = 3.65µm

Search data:
TagsLITHS: nannolith-radiate, N: 3D-radiate, conical, circular, cylindrical, RIM: tiered, CA: process, PROCESS: bifurcate, duocrystalline, length-fast, spine,
CSPH: not known, V-UNITS: spine, V-prominent, R-UNITS: lower-tier, R-prominent, DETAILS: isogyres radial,
MetricsLith size: 5->8µm;
Sources: lith height from OD and slightly extended
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP24 zone (26.84-29.62Ma, top in Chattian stage). Data source: Bown & Dunkley Jones, 2012
First occurrence (base): within NP23 zone (29.62-32.02Ma, base in Rupelian stage). Data source: Bown & Dunkley Jones, 2012

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: S. predistentus group

    References:

    Bergen, J. A., de Kaenel, E., Blair, S. A., Boesiger, T. M. & Browning, E. (2017). Oligocene-Pliocene taxonomy and stratigraphy of the genus Sphenolithus in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 77-112. gs :: view :: open

    Bown, P. R. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs :: view :: open


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    Sphenolithus peartiae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-7-2020

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1309 Go to Archive.is to create a permanent copy of this page - citation notes



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