R. bisecta group
Classification: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> R. bisecta group
Sister taxa: C. floridanus group, R. bisecta group, R. lockeri group, R. parvula group, R. pseudoumbilicus group, R. reticulata group, R. umbilicus group, R. sp.,
Citation: R. bisecta groupRank: species groupNotes & discussion: This group broadly, but not completely, correlates with the general usage of the genus Dictyococcites Black, 1967. That is, any workers who use the genus Dictyococcites will place these species in the genus, but they may also include varying numbers of other species, with closed or nearly closed central areas. The type species of Dictyococcites does not however belong to this group so the name should not be applied to applicable. Moreover some workers apply the name Dictyococcites to any elliptical reticulofenstrids with a closed central area. This is a polyphyletic grouping and so is not acceptable.
Distinguishing features: Elliptical reticulofenestrids, central area closed by very robust, conspicuous distal ‘plug’ (birefringent).
Farinacci & Howe catalog pages:
The morphological data given here can be used on the advanced search page. See also these notes
|Tags||CA: Placoliths: closed-----, |
CSPH: spherical, V-UNITS: none, R-UNITS: all, c-str, distal shield, prox shield, tube, DETAILS: isogyres kinked, isogyres oblique,
|Metrics||Lith size: 3->16µm; |
Notes: As defined this group is essentially restricted to the Paleogene.
Last occurrence (top): at top of Early Pleistocene Sub-Epoch (100% up, 0.8Ma, in Calabrian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Lutetian Stage (23% up, 46.3Ma, in Lutetian stage). Data source: Total of range of species in this database
Plot of occurrence data:
- Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
- Triangles indicate an event for which a precise placement has been suggested
- Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Reticulofenestra
Bown, P. R. & Dunkley Jones, T. (2012). Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research. 32(2): 3-51. gs :: view :: open