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, 2005Rank: SpeciesTaxonomic 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 *
The morphological data given here can be used on the advanced search page. See also these notes
|Tags||LITHS: holococcolith, polygonal, CA: diagonal cross, CROSS-POLARS: V-prominent, |
|Metrics||Lith size: 4->5.5µm; |
Data source notes: lith size from OD & extended slightly
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:
- Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
- Triangles indicate an event for which a precise placement has been suggested
- (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Youngilithus
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