Nannotax3 - ntax_cenozoic - Rhabdosphaera gracilenta Nannotax3 - ntax_cenozoic - Rhabdosphaera gracilenta

Rhabdosphaera gracilenta


Classification: ntax_cenozoic -> Syracosphaerales -> Rhabdosphaeraceae -> Rhabdosphaera -> Rhabdosphaera gracilenta
Sister taxa: R. clavigera, R. gracilenta, R. poculii, R. vitrea, R. xiphos, R. sp.

Taxonomy:

Citation: Rhabdosphaera gracilenta (Bown & Dunkley Jones, 2006) Dunkley Jones et al., 2009
Taxonomic rank: species
Basionym: Blackites gracilentus Bown & Dunkley Jones, 2006
Taxonomic discussion: In SEM the spines of R. gracilenta appear similar in morphology to the extant Rhabdosphaera clavigera Murray & Blackman, 1898 but are formed of less rapidly spiraling elements. The rhabdolith base lacks a radial lath-cycle, and so it was transferred from Blackites to Rhabdosphaera by Dunkley Jones et al. (2009).

NB Orthogrpahy emeneded from R. gracilentus to R. gracilenta by Bown & Newsam 2017

Distinguishing features:
Parent taxon (Rhabdosphaera): Coccoliths without radial lath cycle; coccospheres dimorphic, only some spine-bearing
This taxon: Rhabdoliths with a thin, narrow coccolith base and a narrow spine with an axial canal.

Farinacci & Howe catalog pages: B. gracilentus *

Search data:
LITHS: planolith, elliptical, CA: ca_disjunct, process, CROSS-POLARS: R-prominent,
Lith size: 6->10µm;
Data source notes: lith length from OD
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP21 zone (32.92-34.44Ma, top in Rupelian stage). Data source: Dunkley Jones et al., 2009
First occurrence (base): within NP16 zone (40.40-42.87Ma, base in Lutetian stage). Data source: Bown & Dunkley Jones, 2006

Plot of occurrence data:

References:

Bown, P. R. & Dunkley Jones, T. (2006). New Paleogene calcareous nannofossil taxa from coastal Tanzania: Tanzania Drilling Project Sites 11 to 14. Journal of Nannoplankton Research. 28(1): 17-34. gs

Bown, P. R. & Newsam, C. (2017). Calcareous nannofossils from the Eocene North Atlantic Ocean (IODP Expedition 342 Sites U1403–1411). Journal of Nannoplankton Research. 37(1): 25-60. gs O

Dunkley Jones, T., Bown, P. R. & Pearson, P. (2009). Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophycidae) from the Pande Formation (Kilwa Group), Tanzania. Journal of Systematic Palaeontology. 7(4): 359-411. gs


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Rhabdosphaera gracilenta compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-2-2025

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1196 Go to Archive.is to create a permanent copy of this page - citation notes
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