Nannotax3 - ntax_cenozoic - D. pentaradiatus group Nannotax3 - ntax_cenozoic - D. pentaradiatus group

D. pentaradiatus group


Classification: ntax_cenozoic -> Discoasterales -> Discoasteraceae -> Discoaster -> D. pentaradiatus group
Sister taxa: D. brouweri group, D. pentaradiatus group, D. quinqueramus group, D. variabilis group, D. exilis group, D. musicus group, D. deflandrei group ⟩⟨ D. nodifer group, D. lodoensis group, D. multiradiatus group, D. araneus group, D. sp.

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Discoaster pentaradiatus
Ray tips with acute bifurcations; strongly concavo-convex; birefringent

Discoaster prepentaradiatus
Symmetric with bifurcations; rays planar and all show similar birefringence.
Discoaster prepentaradiatus prepentaradiatus
Discoaster prepentaradiatus plautus
Discoaster styzenii
Discoaster trifolius

Discoaster hamatus
5-rayed; ray tips with clockwise deflected (in distal view) proximal extensions.
Discoaster bolivariae
Discoaster triuncinus

Discoaster bellus
Symmetric 5-rayed species with simple ray tips
Discoaster astellaris
Discoaster gemmulatus

Taxonomy:

Citation: Discoaster pentaradiatus group
taxonomic rank: species group

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: Symmetric 5-rayed, late Neogene, discoasters without large proximal boss

Farinacci & Howe catalog pages:


Morphology:

This is an informal grouping for symmetric 5-rayed discoasters. These species probably do not form a clade but are a characteristic component of Late Miocene and Pliocene assemblages, including several important marker species.

Search data:
Lith size: 7->20µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: This group is confined the Late Miocene and Pliocene and the absence of the group is a useful indication of earlier age. Most individual species are also stratigraphically valuable so this is one of the most stratigraphically vauable groups of nannofossils in the entire Cenozoic.
Last occurrence (top): at top of NN17 zone (100% up, 2.4Ma, in Gelasian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NN8 zone (10.55-10.89Ma, base in Tortonian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Young, J. R. (1998). Neogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 225-265. gs


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D. pentaradiatus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-9-2024

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=423 Go to Archive.is to create a permanent copy of this page - citation notes
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