Pemma bybelliae

Classification: ntax_cenozoic -> Braarudosphaerales -> Braarudosphaeraceae -> Pemma -> Pemma bybelliae
Sister taxa: P. basquense, P. bybelliae, P. papillatum, P. rotundum, P. stradneri, P. triquetra, P. uncinata, P. sp.


Citation: Pemma bybeliae Self-Trail, 2011
Rank: Species

Distinguishing features: Large, circular Pemma with a diagnostic thin base with crenulated edges. Central area consists of a layer of basal thickenings superimposed on the base, resulting in a hazy appearance of the outer edge of the nannolith and a central area more highly birefringent than the edges.

Farinacci & Howe catalog pages: P. bybelliae *

Morphology: Similar in shape to P. rotundum, which lacks the thin base exhibited by P. bybelliae. Pemma balium is the only other described member of this genus to exhibit a thin base, and it is easily distinguished from P. bybelliae by its subcircular outline (Self-Trail 2011).

Size: Diamter 7.5-13.5µm

Search data:
TagsLITHS: nannolith-radiate, pentagonal, CA: pores, CROSS-POLARS: T-prominent,
MetricsLith size: 7->14µm; Segments: 5->5;
Data source notes: lith size (diameter) 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 NP16 zone (40.40-42.87Ma, top in Bartonian stage). Data source: Self-Trail 2011
First occurrence (base): within NP16 zone (40.40-42.87Ma, base in Lutetian stage). Data source: Self-Trail 2011

Plot of occurrence data:


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


Pemma bybelliae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 13-6-2021

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Short stable page link: Go to to create a permanent copy of this page - citation notes

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