Nannotax3 - ntax_cenozoic - B. amplus group Nannotax3 - ntax_cenozoic - B. amplus group

B. amplus group


Classification: ntax_cenozoic -> Syracosphaerales -> Rhabdosphaeraceae -> Blackites -> B. amplus group
Sister taxa: B. morionum group, B. clavus group, B. inflatus group, B. spinosus group, B. amplus group, B. sp.

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Blackites amplus
Spineless Paleogene Blackites described from SEM image, but subsequently paired with LM images of circular coccoliths that are predominantly dark with a brighter centre.

Blackites friedrichii


Blackites furvus
Medium-sized, subcircular-circular coccoliths with broad, low-birefringence shields crossed by strongly curving extinction lines. The central area is narrow or closed and is typically marked by a dark subcircular process.
Blackites cf. B. furvus

Blackites sp. - bases


Taxonomy:

Citation: Blackites amplus group
taxonomic rank: species group
Taxonomic discussion: informal grouping used here to sort species within this large genus

Distinguishing features:
Parent taxon (Blackites): Coccoliths process-bearing with complex base including outer rim, radial lath and lamellar cycles
This taxon: Spine absent or very small

Farinacci & Howe catalog pages:


Size:
The described forms have diameters of 4-6µm which is perhaps rather larger than that of typical spine bases of Blackites but this may simply reflect a bias toward describing the larger forms [JRY 2017]

Search data:
Lith size: 4->6µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of NP21 zone (100% up, 32.9Ma, in Rupelian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP14 zone (46.29-49.11Ma, base in Ypresian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:


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B. amplus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-9-2024

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=57 Go to Archive.is to create a permanent copy of this page - citation notes
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