Nannotax3 - ntax_cenozoic - Toweius gammation

Citation: Toweius gammation(Bramlette & Sullivan, 1961) Romein, 1979

Basionym: Coccolithites gammation Bramlette & Sullivan, 1961

Synonyms: Girgisia gammation Varol 1989; Cyclicargolithus gammation; Cyclococcolithus gammation; Cyclococcolithina gammation; Calcidiscus gammation; Markalius gammation;

Taxonomic discussion: Very distinctive appearance in LM and has been placed in a separate genus, Girgisia Varol, 1989, by some authors (e.g. Varol, 1989, Shamrock & Watkins 2008).

Distinguishing features: Medium sized; circular; central area with bright central plug crossed by strongly curving swastika-like extinction lines. Shield elements are usually conspicuous in LM.

Geological Range:
Last occurrence (top): within NP14 zone (46.29-49.11Ma, top in Lutetian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): within NP11 zone (53.70-54.17Ma, base in Ypresian stage). Data source: [PRB rough estimate]

References:

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 V O

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

Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. gs

Romein, A. J. T. (1979). Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletin. 22: 1-231. 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 O

Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs

Shepherd, C. L. & Kulhanek, D. K. (2016). Eocene nannofossil biostratigraphy of the mid-Waipara River section, Canterbury Basin, New Zealand. Journal of Nannoplankton Research. 26(1): 33-59. gs V O

Varol, O. (1989b). Eocene calcareous nannofossils from Sile (northwest Turkey). Revista Española de Micropaleontología. 21: 273-320. gs V O

Tags	LITHS: placolith, circular, CA: ca_conjunct, grill, vacant, CSPH: equant, monomorphic, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
Metrics	Lith size: 5->9µm;

Toweius gammation

References:

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