|Daughter taxa (time control age-window is: 0-800Ma)||Granddaughter taxa|
4-rayed, symetric, ray tips curved downwards
5-7 almost wedge-shaped rays separated by very narrow and deep interradial incisions (Romein 1979)
A discoaster with 8 bifurcating rays without a prominent central knob. The rays form an overlapping pattern that spirals dextrally and is distinctive of this species.
≥8 near-parallel-sided rays with rounded to pointed tips that radiate with little free length from a large circular central area. May show inter-ray ridges, a low central boss, and the development of nodes towards the ray tips.
Usually 8 rays with free ray length that approaches half the diameter of the central area or greater and prominent lateral nodes and pointed ray tips.
6-9 rayed stellate discoaster with prominent lateral nodes on their rays and ray-end notches or bifurcations.
5-6 rayed stellate discoasters; ray tips with bifurcation and lateral nodes (resemble spanners).
>6 rayed stellate discoasters; ray tips with bifurcations (similar to D. deflandrei apart from number of rays)
5 rayed stellate discoaster with long free rays of uniform width terminating in a flat or slightly notched ray-end. May show poorly developed unpaired lateral nodes on some rays.
|Discoaster tani ornatus|
5 rayed large stellate discoaster with prominent lateral nodes on their rays, ray-end notches or bifurcations and a stellate central boss.
Ornate 5-rayed discoaster
5 rayed, usually very large, stellate discoaster, with wide bifurcate ray tips.
5-6 rayed discoaster with broad central area that is distinctly elevated on both faces. The rays are narrow and free for around half their length. Paired lateral nodes just before the ray tips are present in some specimens
5-7 (typically 6) rayed, simple, stellate discoasters with broad, tapering rays joined along 1/2 their length.
4- to 7-rayed very large (20-45µm) discoaster, with long, thin, tapering free rays (broadest at their mid-point) and small central area.
Parent taxon (Discoaster): Radiate nannoliths with each ray formed of a discrete crystal-unit, with the c-axes perpendicular to the nannolith surface.
This taxon: Stellate discoasters with straight rays; rays free for >1/3 of their length; rays with bifurcations or nodes; 5-10 rays
Farinacci & Howe catalog pages:
|Lith size: 5->45µm;|
Last occurrence (top): at top of NP23 zone (100% up, 29.6Ma, in Rupelian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP7 zone (58.7-58.97Ma, base in Thanetian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Short stables page link: https://mikrotax.org/Nannotax3/index.php?id=422 Go to Archive.is to create a permanent copy of this page - citation notes
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