C. floridanus group


Classification: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> C. floridanus 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)
Coccoliths large (>11µm), usually sub-circular.
Small (3-6 µm), sub-circular with broad central opening (ca 20-25% of coccoilth width)
Coccoliths circular to sub-circular with small central-area, <11µm in width.
Medium sized circular reticulofenestrids with narrow, closed central area.
Small (3-5µm) circular reticulofenestrid with narrow or closed central area and few elements (individual elements clearly visible in lm)
Specimens which cannot be assigned to established species

Taxonomy:

Citation: C. floridanus group
Rank: species group
Synonyms: Cyclicargolithus Bukry 1971
Notes & discussion: The genus Cyclicargolithus Buky 1971 is widely used and the taxonomic concept is straightforward - circular reticulofenestrids with a narrow central area. However, these intergrade with Reticulofenestra, so it can be difficult to assign some specimens. Moreover the genus is phylogenetically problematic since it is likely that it both evolved from a Paleogene Reticulofenestra species and gave rise to Neogene Reticulofenestra species. So, we regard Cyclicargolithus as a sub-group of Reticulofenestra rather than a genuinely separate genus.

Distinguishing features: Subcircular to broadly-elliptical reticulofenestrids with a narrow central area (spanned by delicate proximal net, not visible in lm)

Farinacci & Howe catalog pages: Cyclicargolithus *

Search data:
TagsLITHS: sub-circular, RIM: rim-broad,
CSPH: spherical, V-UNITS: none, R-UNITS: all, c-str, distal shield, prox shield, tube, DETAILS: isogyres kinked, isogyres oblique,
MetricsLith size: 3->16µm;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Common in the Eocene and dominant, lower Oligocene-lower Miocene.
Last occurrence (top): in upper part of Serravallian Stage (80% up, 12.1Ma, in Serravallian stage). Data source: Total of range of species in this database
First occurrence (base): in upper part of Thanetian Stage (62% up, 57.2Ma, in Thanetian 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

Bukry, D. (1971b). Cenozoic calcareous nannofossils from the Pacific Ocean. San Diego Society of Natural History Transactions. 16: 303-327. gs :: ::


nannotaxlogo400px

C. floridanus group compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-5-2020

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=165 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics