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:
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:
LITHS: placolith, elliptical, CA: vacant, CSPH: equant, monomorphic, |
Lith size: 1.5->4µm; |
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:
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. gsReferences:
Centumgemina compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-10-2024
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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