|Daughter taxa (time control age-window is: 0-800Ma)|
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.
Rhomboid liths with small, marginal projections from the rim and two oblique, parallel, central area bars. Low birefringence image in XPL.
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.
A rectangular to square, box-like holococcolith constructed from four crystallographically distinct units, with at least two protrusions on each side.
Square, medium-sized, non-birefringent holoccolith with a narrow rim with small marginal projections, spanned by cross bars parallel with the sides.
Elongate rhomboid liths with three oblique, parallel, central area bars. Low birefringence image in XPL.
Specimens which cannot be assigned to any established species
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;|
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:
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