Taxonomic discussion: This species should be recombined in Braarudosphaera or Pentaster, since the sutures do not run along the rays. [my interpretation - JRY 2020]
Parent taxon (Micrantholithus): Pentaliths with sutures emerging through corners; edge often indented giving stellate outline
This taxon: Micrantholithus with bifurcate ray-like extension from each segment (sutures do not go along arms). Resembles a discoaster but evidently shows the birefringence of a pentalith and a specimen of M. concinnus with short rays is illustrated from the same sample so the identification seems well-founded.
Farinacci & Howe catalog pages: M. tinus *
Morphology: Some similarity to M. bramlettei but rays are much longer.
|Tags||LITHS: nannolith-radiate, pentagonal, CROSS-POLARS: T-prominent,|
|Metrics||Lith size: 18->22µm; Segments: 5->5; Liths per sphere: 12->12|
Data source notes: lith size (diameter) from OD; lith numbers assumed from geometry
Last occurrence (top): within NP13 zone (49.11-50.50Ma, top in Ypresian stage). Data source: Kapellos & Schaub 1973
First occurrence (base): within NP12 zone (50.50-53.70Ma, base in Ypresian stage). Data source: Kapellos & Schaub 1973
Plot of occurrence data:
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=872 Go to Archive.is to create a permanent copy of this page - citation notes