D. pentaradiatus group


Classification: Coccolithophores -> 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: (blue => in age window 0-800Ma) Granddaughter taxa
Ray tips with acute bifurcations; strongly concavo-convex; birefringent

Symmetric with bifurcations; rays planar and all show similar birefringence.

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

Symmetric 5-rayed species with simple ray tips

Taxonomy:

Citation: Discoaster pentaradiatus group
Rank: species group

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

Farinacci & Howe catalog pages:


Morphology remarks: 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:
TagsLITHS: nannolith-radiate, star-shaped, RIM: free-rays-long,
CSPH: not known, V-UNITS: all, R-UNITS: none, DETAILS: 1ou,
MetricsLith size: 7->20┬Ám;
Sources:
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): in lower part of Gelasian Stage (26% up, 2.4Ma, in Gelasian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Tortonian Stage (17% up, 10.9Ma, in Tortonian stage). Data source: Total of range 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


nannotaxlogo400px

D. pentaradiatus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-9-2019

Taxon Search:
Advanced Search

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



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics