Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
| Discoaster anartios 15-20 rays. Large to very large, typically asymmetric, rosette-shaped discoaster with a tall narrow stem on one side and 15-20 irregularly shaped curving rays that are free rays for around half the diameter. | ||||
| Discoaster salisburgensis var. villosus 10-14 rays. | ||||
| Discoaster araneus 7-9 rays. Large to very large, typically asymmetric discoaster with a prominent boss on one side and 7-9 tapering rays that have variable curvature and free length (1/3 to 2/3 of total ray length). | ||||
| Discoaster acutus 6 or less rays; Typically six rayed, stellate (star-shaped) discoaster with relatively long, tapering free rays comparable in length to the central area width. The central area has inter-ray ridges and a small but prominent central boss on one side. The rays look rather ragged and sometimes appear to be asymmetrically arranged. | ||||
Distinguishing features:
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: Irregular "malformed" discoasters characteristic of the PETM excursion
Farinacci & Howe catalog pages:
See also: Discoaster salisburgensis - regular counterpart to these morphologies according to Bralower & Self-Trail (2016);
Search data:| Lith size: 10->25µm; |
Geological Range:
Notes: These taxa are characteristic of the unusual assemblages developed during the Paleocene-Eocene Thermal maximum (PETM)
Last occurrence (top): at top of NP10 zone (100% up, 54.2Ma, in Ypresian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP9 zone (55.86-57.21Ma, base in Thanetian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Bralower, T. J. & Self-Trail, J. (2016). Nannoplankton malformation during the Paleocene-Eocene Thermal Maximum and its paleoecological and paleoceangraphic significance. Paleoceanography. 31: 1-17. gsReferences:

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D. araneus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-1-2026
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=418 Go to Archive.is to create a permanent copy of this page - citation notes |
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