Youngilithus arcaeformis

Classification: ntax_cenozoic -> Holococcoliths -> fossil holococcoliths -> Youngilithus -> Youngilithus arcaeformis
Sister taxa: Y. arcaeformis, Y. bipons, Y. oblongatus, Y. pyxis, Y. quadraeformis, Y. transversipons, Y. sp.


Citation: Youngilithus arcaeformis Bown, 2005
Rank: Species
Taxonomic discussion: Similar to Orthozygus brytika but with geometric outline and lateral rim spines.

Distinguishing features: Polygonal, medium-sized, non-birefringent holococcolith with a narrow rim spanned by diagonal cross-bars. The rim is coffin-shaped (like a diamond with flattened ends) and usually shows small marginal projections.

Farinacci & Howe catalog pages: Y. arcaeformis *

Search data:
TagsLITHS: holococcolith, polygonal, CA: diagonal cross, CROSS-POLARS: V-prominent,
MetricsLith size: 4->5.5µm;
Data source notes: lith size from OD & extended slightly
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP15c subzone (42.87-44.12Ma, 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. (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


Youngilithus arcaeformis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-2-2021

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