Nannotax3 - ntax_cenozoic - Discoaster acutus

Discoaster acutus

Classification: ntax_cenozoic -> Discoasterales -> Discoasteraceae -> Discoaster -> D. araneus group -> Discoaster acutus
Sister taxa: D. anartios, D. salisburgensis var. villosus, D. araneus, D. acutus


Citation: Discoaster acutus Bown, 2005
Rank: Species
Taxonomic discussion: Bralower & Self-Trail (2016) argue that this is better regarded as a sub-species of D. salisburgensis.

Distinguishing features:
Parent taxon (D. araneus group): Irregular "malformed" discoasters characteristic of the PETM excursion
This taxon: 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.

Farinacci & Howe catalog pages: D. acutus * , D. aegyptiacus aegyptiacusr [no catalog entry yet]



See also: Discoaster salisburgensis - the non-malformed species this form is derived from, according to Bralower & Self-Trail (2016);

Search data:
LITHS: nannolith-radiate, asymmetric, star-shaped, CA: process, CROSS-POLARS: 1ou, V-prominent,
Lith size: 10->20µm; Segments: 6->6;
Data source notes: size from OD and specs illustrated in Bralower & Self-Trail 2016
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP10 zone (54.17-55.86Ma, top in Ypresian stage). Data source: Bown, 2005
First occurrence (base): within NP9 zone (55.86-57.21Ma, base in Thanetian stage). Data source: [PRB rough estimate]

Plot of occurrence data:


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 O

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. gs


Discoaster acutus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-9-2022

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