Classification: ntax_cenozoic -> Holococcoliths -> fossil holococcoliths -> Youngilithus
Sister taxa: Clathrolithus, Corannulus, Daktylethra, Holodiscolithus, Lanternithus, Multipartis, Octolithus, Orthozygus, Quadrilateris, Semihololithus, Varolia, Youngilithus, Zygrhablithus, Unidentified fossil holococcoliths

Daughter taxa (time control age-window is: 0-800Ma)
Youngilithus arcaeformis
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.
Youngilithus bipons
Rhomboid liths with small, marginal projections from the rim and two oblique, parallel, central area bars. Low birefringence image in XPL.
Youngilithus oblongatus
A rectangular, medium-sized, non-birefringent holococcolith with lateral rim projections. The sides of the rectangle are formed from narrow crystallographically distinct units, and some specimens have an internal transverse bar.
Youngilithus pyxis
A rectangular to square, box-like holococcolith constructed from four crystallographically distinct units, with at least two protrusions on each side.
Youngilithus quadraeformis
Square, medium-sized, non-birefringent holoccolith with a narrow rim with small marginal projections, spanned by cross bars parallel with the sides.
Youngilithus transversipons

Elongate rhomboid liths with three oblique, parallel, central area bars. Low birefringence image in XPL.

Youngilithus sp.
Specimens which cannot be assigned to any established species


Citation: Youngilithus Bown, 2005
Rank: Genus
Type species: Youngilithus oblongatus Bown, 2005

Distinguishing features: Geometrically shaped non-birefringent holococcoliths typically possessing lateral rim spines and central area bars.

Farinacci & Howe catalog pages: Youngilithus *

Search data:
TagsLITHS: holococcolith, hollow, CROSS-POLARS: V-prominent,
MetricsLith size: 3->8µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): in lower part of Bartonian Stage (22% up, 40.4Ma, in Bartonian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Selandian Stage (4% up, 61.5Ma, in Selandian stage). Data source: Total of range of species in this database

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 compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-7-2021

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