Taxonomy:
Distinguishing features: Pontosphaera with plate that has oblique marginal furrows and oblique pores, and larger pores towards the centre; there may be two central longitudinal slits; rim narrow.
Farinacci & Howe catalog pages: P. clinosulcata *
Morphology: Medium to large elliptical Pontosphaera with a plate that is scalloped towards its outer edge. The scalloping is defined by narrow inclined ridges, which run inwards towards the centre. There are inclined furrows between the ridges and inclined elongate pores; there may be two central longitudinal slits. The rim is narrow and difficult to distinguish in XPL.
Tags | LITHS: murolith, elliptical, CA: pores, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 7->10µm; Data source notes: lith size from OD and slightly extended |
Geological Range:
Last occurrence (top): within NP15b subzone (44.12-45.49Ma, top in Lutetian stage). Data source: Bown 2005
First occurrence (base): within NP15b subzone (44.12-45.49Ma, base in Lutetian stage). Data source: Bown 2005
Plot of occurrence data:
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 V O Bown, P. R. (2005d). Palaeogene calcareous nannofossils from the Kilwa and Lindi areas of coastal Tanzania (Tanzania Drilling Project 2003-4). Journal of Nannoplankton Research. 27(1): 21-95. gs V O Self-Trail, J. (2011). Paleogene Calcareous Nannofossils of the South Dover Bridge core, Southern Maryland (USA). Journal of Nannoplankton Research. 32(1): 1-28. gs V OReferences:
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Pontosphaera clinosulcata compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-2-2021
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