Youngilithus
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.
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 |  | | | Youngilithus bipons
Rhomboid liths with small, marginal projections from the rim and two oblique, parallel, central area bars. Low birefringence image in XPL.
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 |  |  |  | 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.
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 |  |  |  | Youngilithus pyxis
A rectangular to square, box-like holococcolith constructed from four crystallographically distinct units, with at least two protrusions on each side.
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 |  |  |  | Youngilithus quadraeformis
Square, medium-sized, non-birefringent holoccolith with a narrow rim with small marginal projections, spanned by cross bars parallel with the sides.
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 |  |  | | Youngilithus transversipons
Elongate rhomboid liths with three oblique, parallel, central area bars. Low birefringence image in XPL.
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| | | | Youngilithus sp.
Specimens which cannot be assigned to any established species
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Taxonomy:
Citation: Youngilithus Bown, 2005Rank: GenusType 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:
| Tags | LITHS: holococcolith, hollow, CROSS-POLARS: V-prominent, |
| Metrics | Lith 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:
- 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
- Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: fossil holococcoliths
References:
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
