|Daughter taxa (time control age-window is: 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
Distinguishing features: 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.
|Metrics||Lith size: 7->20µm;|
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:
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