R. reticulata group


Classification: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> R. reticulata 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.,

Daughter taxa: (blue => in age window 0-800Ma)
Small (up to 4µm) species with wide central area and robust grill
Medium to large (~8-12µm), circular reticulofenestrids with narrow central area crossed by a distinctive, robust, visible net.
Similar to R. reticulata but >12µm long
Similar to R. reticulata but with broad tube and closed central area.
Similar to R. reticulata but smaller and without visible net
Morphotypes intergrading with R. reticulata but lacking the distinctive central area structure

Taxonomy:

Citation: R. reticulata group
Rank: species group
Notes & discussion: Broadly, but not completely, correlates with the general usage of the genus Cribrocentrum Perch-Nielsen, 1971. This group includes the only strictly circular Paleogene reticulofenestrids but some smaller forms may have imperceptible (or lost) nets and there is some evidence of transitional subcircularity.

Distinguishing features: Typically circular reticulofenestrids with relatively narrow circular central area with robust grill (clearly visible in lm).

Farinacci & Howe catalog pages:

Search data:
TagsLITHS: sub-circular,
CSPH: spherical, V-UNITS: none, R-UNITS: all, c-str, distal shield, prox shield, tube, DETAILS: isogyres kinked, isogyres oblique,
MetricsLith size: 5->16µm;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: As defined this group is essentially restricted to the middle-upper Eocene.
Last occurrence (top): near top of Priabonian Stage (86% up, 34.4Ma, in Priabonian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Ypresian Stage (28% up, 53.7Ma, in Ypresian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

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


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R. reticulata group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 30-5-2020

Taxon Search:
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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=1150 Go to Archive.is to create a permanent copy of this page - citation notes



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