Reticulofenestra umbilicus


Ancestry: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> R. umbilicus group -> Reticulofenestra umbilicus
Sister taxa: R. umbilicus, R. dictyoda, R. hillae, R. foveolata, R. hampdenensis, R. hesslandii, R. moorei, R. circus, R. circus var. lata, R. wadeae, R. maceria Shafik 1989, R. oamaruensis,

Short diagnosis: Very large (>14 µm) elliptical reticulofenestrids, with delicate net


Taxonomy:

Citation: Reticulofenestra umbilicus (Levin, 1965) Martini & Ritzkowski, 1968
Rank: Species
Basionym: Coccolithus umbilicus Levin, 1965

Farinacci & Howe catalog pages: Coccolithus umbilicus *

Short diagnosis: Very large (>14 µm) elliptical reticulofenestrids, with delicate net


Size: Holotype length 16.1µm.

Geological Range:
Notes: The first appearance of very large, >14μm, elliptical reticulofenestrids (i.e. R. umbilicus) has long been used as a distinctive stratigraphic marker (e.g. Backman & Hermelin, 1986). In the Exp. 342 material these sizes are attained by subcircular to elliptical reticulofenestrids (similar to R. wadeae and R. umbilicus) in Subzone NP15b, around 3 m.y. prior to the level typically cited for this biohorizon. Agnini et al. (2014) suggest that the use of the first common occurrence of R. umbilicus may represent a more consistent horizon, above the last occurrence of C. gigas. [Bown & Newsam 2017]
Last occurrence (top): at top of NP22 zone (100% up, 32Ma, in Rupelian stage). Data source: zonal marker (see Perch-Nielsen 1985)
First occurrence (base): within NP16 zone (40.40-42.87Ma, base in Lutetian stage). Data source: Perch-Nielsen 1985

Plot of occurrence data:

References:

Agnini, C.; Fornaciari, E.; Raffi, I.; Catanzariti, R.; Pälike, H.; Backman, J. & Rio, D., (2014). Biozonation and biochronology of Paleogene calcareous nannofossils from low and middle latitudes.

Backman, J. & Hermelin, J.O.R., (1986). Morphometry of the Eocene nannofossil Reticulofenestra umbilicus lineage and its biochronological consequences. Palaeogeography Palaeoclimatology Palaeoecology, 57: 103-116.

Backman, J.; Pestiaux, P.; Zimmerman, H. & Hermelin, J.O.R., (1986). Paleoclimatic and paleoceanographic development in the Pliocene North Atlantic: Discoaster accumulation and coarse fraction data. In: Summerhayes, C.P. and Shackleton, N.J. (Editors), North Atlantic Paleoceanography. Geological Society of London Special Publication, pp. 231-242.

Bown, P.R. & Newsam, C., (2017). Calcareous nannofossils from the Eocene North Atlantic Ocean (IODP Expedition 342 Sites U1403–1411). Journal of Nannoplankton Research, 37(1): 25-60.

Levin, H.L., (1965). Coccolithophoridae and related microfossils from the Yazoo Formation (Eocene) of Mississippi. Journal of Paleontology, 39(2): 265-272.

Martini, E. & Ritzkowski, S., (1968). Was ist das 'Unter-Oligozän'? Eine Analyse der Beyrich'schen und v Koenen'schen Fassung der Stufe mit Hilfe des fossilen Nannoplanktons. Nachr Akad Wiss Gottingen; II Mathematisch-Physikalische Klasse, 1968, 13: 231-250.

Perch-Nielsen, K., (1985). Cenozoic calcareous nannofossils. In: Bolli, H.M., Saunders, J.B. and Perch-Nielsen, K. (Editors), Plankton Stratigraphy. Cambridge University Press, Cambridge, pp. 427-555.


Nannotax3 - Coccolithophores - Reticulofenestra umbilicus by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-4-2017

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Simun Ascic (Zagreb University, Croatia)
Description says <14µm. probably should be >14 µm
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Paul Bown (Univeristy College London, UK)
Well spotted! Just fixed it.
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