Nannotax3 - ntax_cenozoic - Centumgemina Nannotax3 - ntax_cenozoic - Centumgemina

Centumgemina


Classification: ntax_cenozoic -> Coccolith families inc sed -> Coccolith genera inc sed -> Centumgemina
Sister taxa: Aliculosphaera, Biantholithus, Camuralithus, Centumgemina, Craterolithus, Ellipsolithus, Gladiolithus, Ilselithina, Leesella, Luminocanthus, Pedinocyclus, Petasus

Daughter taxa (time control age-window is: 0-800Ma)
Centumgemina scissurata
Minute (1.5-2µm) irregularly oblong placoliths apparently composed of a single cycle of elements; central area an open slit.
Centumgemina simplex
Simllar to C. scissurata but larger
Hornibrookina apellanizii
Very small (2-3.5µm) with a rhombohedral shape and a wide central area.

Taxonomy:

Citation: Centumgemina Mai & Aubry 2005
taxonomic rank: Genus
Type species: Prinsius scissuratus Mai 2001
Taxonomic discussion: Genus proposed for two Danian species of small coccoliths earlier placed tentatively in Prinsius, but apparently having distinctly simpler construction.

Distinguishing features:
Parent taxon (Coccolith genera inc sed): Heterococcolith genera which cannot be assigned to any family
This taxon: Small oblong placolith coccoliths with the rim apparently formed from a single cycle of elements. Addtional elements are present in the central area of C. simplex but absent from it (possibly due to preservation) in C. scissurata. Numerous coccoliths per coccosphere.

Farinacci & Howe catalog pages: Centumgemina *


Morphology:

Aubry & Bord (2009) noted that there are similarities between these very small coccoliths and Ellipsolithus, which has an otherwise cryptic origin slightly later in the Paleocene. They proposed the family Ellipsolithaceae for these two genera. In Ellipsolithus both shields are R-units if this proves to also be the case in Centumgemina then this grouping would be worth following.

Search data:
LITHS: placolith, elliptical, CA: vacant,
CSPH: equant, monomorphic,
Lith size: 1.5->4µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Only ever recorded from the basal Danian of the Maastricht area, but the genus may prove more widespread when SEM studies are carried out on well preserved material from elsewhere.
Last occurrence (top): at top of NP1 zone (100% up, 65.5Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Aubry, M. -P. & Bord, D. (2009). Reshuffling the cards in the photic zone at the Eocene/Oligocene boundary. In, Koeberl, C. & Montanari, A. (eds) The Late Eocene Earth—Hothouse, Icehouse, and Impacts. Geological Society of America, Special Papers . 452: 279-301. gs

Mai, H. & Aubry, M. -P. (2005). Centumgemina, n. gen., a new coccolithophorid taxon from Geulhemmerberg airshaft section, Lower Paleocene, The Netherlands. Micropaleontology. 51(3): 262-. gs

Mai, H. (2001). New coccolithophorid taxa fom the Guelhemmerberg airshaft. Lower Paleocene, The Netherlands. Micropaleontology. 47: 144-154. gs


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Centumgemina compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-10-2024

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=245 Go to Archive.is to create a permanent copy of this page - citation notes
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