Nannotax3 - ntax_cenozoic - Hexadelus Nannotax3 - ntax_cenozoic - Hexadelus


Classification: ntax_cenozoic -> Braarudosphaerales -> Braarudosphaeraceae -> Hexadelus
Sister taxa: Braarudosphaera, Hexadelus, Micrantholithus, Pemma, Pentaster

Daughter taxa (time control age-window is: 0-800Ma)
Hexadelus archus
Hexagonal formed of 6 flat plates, each an eqiulateral triangle


Citation: Hexadelus Shamrock & Watkins (2012)
Rank: Genus
Type species: Hexadelus archus Shamrock & Watkins 2012

Distinguishing features:
Parent taxon (Braarudosphaeraceae): Coccospheres pentagonal dodecahedra formed of five pentagonal plates
This taxon: Thin nannoliths similar to Braarudosphaera but with 6 segments - usually occur as isolated segments

Farinacci & Howe catalog pages: Hexadelus


Isolated segments are equilateral triangles or wedge shaped, with 60° interior angles (vs. 72° for pentalith segments)

Phylogenetic relations

Tentatively placed in the Braarudosphaeraceae here as they appear similar to pentaliths except for 6 fold symmetry but good observations are not available on crystallographic orientation or substructure.

Search data:
LITHS: nannolith-radiate, polygonal, CROSS-POLARS: T-prominent,
Lith size: 3->7µm; Segments: 6->6;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): in lower part of Rupelian Stage (17% up, 32.9Ma, in Rupelian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Priabonian Stage (20% up, 37Ma, in Priabonian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Bown, P. R. & Dunkley Jones, T. (2006). New Paleogene calcareous nannofossil taxa from coastal Tanzania: Tanzania Drilling Project Sites 11 to 14. Journal of Nannoplankton Research. 28(1): 17-34. gs V O

Shamrock, J. L. & Watkins, D. K. (2012). Eocene calcareous nannofossil biostratigraphy and community structure from Exmouth Plateau, Eastern Indian Ocean (ODP Site 762). Stratigraphy. 9(1): 1-11. gs


Hexadelus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-3-2023

Taxon Search:
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AphiaID: not found
Short stables page link: Go to to create a permanent copy of this page - citation notes

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