Reticulofenestra pseudoumbilicus


Classification: Coccolithophores -> Isochrysidales -> Noelaerhabdaceae -> Reticulofenestra -> R. pseudoumbilicus group -> Reticulofenestra pseudoumbilicus
Sister taxa: R. calicis, R. pseudoumbilicus, R. haqii, R. minuta, R. rotaria, R. minutula, R. asanoi,

Short diagnosis: Medium to large size reticulofenestrid with central opening


Taxonomy:

Citation: Reticulofenestra pseudoumbilicus (Gartner, 1967) Gartner, 1969
Rank: Species
Basionym: Coccolithus pseudoumbilicus Gartner, 1967
Variants:
Notes & discussion: For biostratigraphy it is better to separate the >7µm specimens (e.g.: Rio et al., 1990; Raffi et al., 1995); i.e. a definition of >7µm is preferable for unambiguous identification of both the NN15/16 boundary (last occurrence of R. pseudoumiblicus) and the NN10A/B boundary (start of small Reticulofenestra interval/R.pseudoumbilicus paracme). In industry it is now commonplace to use a defnition of >8µm (de Kaenel pers. comm.). See Young (1990) for an extended discussion of this species.
The Palaeogene species R. dictyoda is essentially identical to R. pseudoumbilicus

Farinacci & Howe catalog pages: Coccolithus pseudoumbilicus * Coccolithus tenuistriatus * Reticulofenestra ampliumbilicus * Reticulofenestra pseudoumbilicus amplus *

Short diagnosis: Medium to large size reticulofenestrid with central opening


Morphology remarks: Coccoliths >5µm (cf. e.g.: Backman, 1980; Young, 1991). Often dominates Middle Miocene - Early Pliocene assemblages.

Search data:
TagsLITHS: placolith, elliptical, CA: grill, vacant,
CSPH: spherical, monomorphic, V-UNITS: none, R-UNITS: all, c-str, distal shield, prox shield, tube, DETAILS: ca_conjunct, isogyres kinked, isogyres oblique, rim-unicyclic,
MetricsLith size: 5->12µm;
Sources:
The morphological data given here can be used on the advanced search page. See also these notes

See also: Reticulofenestra perplexa - form with closed central characteristic of the Neogene of the Southern Ocean;;

Geological Range:
Last occurrence (top): at top of NN15 zone (100% up, 3.7Ma, in Zanclean stage). Data source: zonal marker, e.g. Young 1998
First occurrence (base): within NN4 zone (14.91-17.95Ma, base in Burdigalian stage). Data source: Young 1998

Plot of occurrence data:

References:

Driever, B.W.M., (1988). Calcareous nannofossil biostratigraphy and paleoenvironmental interpretation of the Mediterranean Pliocene. Utrecht Micropaleontological Bulletin, 36: 245.

Gartner, S., (1967). Calcareous nannofossils from Neogene of Trinidad, Jamaica, and Gulf of Mexico. Paleontological Contributions. University of Kansas, 29: 1-7.

Gartner, S., (1969). Correlation of Neogene planktonic foraminifera and calcareous nannofossil zones. Transactions of the Gulf Coast Association of Geological Societies, 19: 585-599.

Gartner, S., (1992). Miocene nannofossil chronology in the North Atlantic, DSDP Site 608. Marine Micropaleontology, 18: 307-331.

Haq, B.U., (1976). Coccoliths in cores from the Bellinghausen abyssal plain and Antarctic continental rise (DSDP Leg 35). Initial Reports of the Deep Sea Drilling Project, 35: 557-567.

Kamptner, E., (1963). Coccolithineen-Skelettreste aus Tiefseeablagerungen des Pazifischen Ozeans. Annalen des Naturhistorischen Museums in Wien, 66: 139-204.

Martini, E., (1979). Calcareous nannoplankton and silicoflagellate biostratigraphy at Reykjanes Ridge, northeastern North Atlantic (DSDP Leg 49, Sites 407 and 409). Initial Reports of the Deep Sea Drilling Project, 49: 533-549.

Theodoridis, S., (1984). Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin, 32: 1-271.

Varol, O., (1989). Calcareous nannofossil study of the central and western Solomon Islands., Circum-Pacific Council for Energy and Mineral Resources Earth Sciences. Geology and offshore resources of Pacific island arcs, pp. 239-268.

Wise, S.W., (1983). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 71 in the Falkland Plateau region, Southwest Atlantic Ocean. Initial Reports of the Deep Sea Drilling Project, 71: 481-550.

Young, J.R., (1998). Neogene. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 225-265.


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Reticulofenestra pseudoumbilicus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-12-2017

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Comments (3)

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Ines Galovic (Croatia)
Isn't it Gartners' Reticulofenestra from 1969 R. pseudoumbilica, that you refer to in Citation but as pseudoumbilicus or I missed something?
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Jeremy Young (UCL, UK)
Gartner did indeed call the taxon Reticulofenestra pseudoumbilica and this spelling was widely used. However, pseudoumibilicus is a noun not an adjective and so cannot change gender. Hence the correct spelling is pseudoumbilicus.Shirley van Heck discussed this in an article on the ICBN"""
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Ines Galovic (CGS, Croatia)
Thank you Jeremy on explanation, I didn't check it is it a noun or not and rely on expert's knowledge, but haven't been sure till now.
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Mike Styzen (Noble Energy, US)
The extinction or LCO of the closed central area variant/morphotype/species, usually under the name Dictyococcites antarcticus, is used in the Gulf of Mexico as a stratigraphic marker in the Early Pliocene, probably within NN 15. Wei (1990) contended that this taxon is a junior synonym of Reticulofenestra perplexa (Burns) which was described as being an order of magnitude different in size. The (informal) consensus amongst GOM workers appears to be that Burns had the unfortunate experience of describing something that did not in fact exist, and should therefore be ignored. Common usage continues to be D. antarcticus.
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Shirley van Heck (Shell International, US)
Specimens between 5 um and 7 um have been described by Sato et al 1991 as Reticulofenestra ampla. This species has a LAD in NN16. (ref.: Sato, T., Kameo, K., Takayama, T., 1991 - Coccolith biostratigraphy of the Arabian Sea. Proc. ODP Sci. Res., 117: 37 - 54)
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Jeremy Young (NHM, UK)
I do mention R. ampla on the minutula page, and suggest it should be regarded as a synonym of R. minutula. That is plainly not right since I also gave 5 microns as the maximum size for R. minutula. recognising these medium size reticulos in the late Pliocene is useful. There is a problem that R. ampla Sato is a junior homonym of R. ampla Theodoridis, but it would be straightforward to propose a substitute name.
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