Neochiastozygus imbriei

Classification: Coccolithophores -> Zygodiscales -> Zygodiscaceae -> Neochiastozygus -> Neochiastozygus imbriei
Sister taxa: N. concinnus, N. denticulatus, N. digitosus, N. distentus, N. eosaepes, N. imbriei, N. junctus, N. macilentus, N. modestus, N. perfectus, N. pusillus, N. rosenkrantzii, N. saepes, N. substrictus, N. tenansa, N. sp.,


Citation: Neochiastozygus imbriei Haq & Lohmann, 1976
Rank: Species
Notes & discussion: In SEM these coccoliths show the presence of additional lateral bars and therefore resemble the smaller (~<3 µm) Danian species Chiastozygus ultimus Perch-Nielsen, 1981, Neochiastozygus denticulatus (Perch-Nielsen, 1969) and Neochiastozygus primitivus Perch-Nielsen, 1981, which were informally grouped as the Neochiastozygus ‘asymmetrical species’ by van Heck & Prins (1987).

Distinguishing features: Small Neochiastozygus with asymmetric cross bars rotated from axial by 10-20°.

Farinacci & Howe catalog pages: Neochiastozygus imbriei * , ,

Search data:
TagsLITHS: murolith, elliptical, RIM: outer wall acw-imbricate, rim-narrow, CA: cross, cross-diagonal-asym,
CSPH: not known, V-UNITS: c-str, outer-rim, R-UNITS: inner-rim, DETAILS: ca_disjunct, rim-bicyclic,
MetricsLith size: 3->8µm;
Sources: lith size from illustrated specimens (OD range of 6-9µm seems to high)
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NP11 zone (53.70-54.17Ma, top in Ypresian stage). Data source: Bown 2005 (Varol 1989 records much lower top, witihn NP4)
First occurrence (base): within NP4 zone (61.51-63.25Ma, base in Danian stage). Data source: Varol, 1989, fig. 12.5

Plot of occurrence data:

  • Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes
  • Note to users in China - the diagram may not plot unless you use a VPN since I use google services on the website. If this is a problem please contact me 谢谢.
  • Taxon plotted: Neochiastozygus imbriei, synonyms included - Neochiastozygus imbrei; Neochiastozygus imbriei; space-time plot :: Samples map :: Parent: Neochiastozygus


    Haq, B. U. & Lohmann, G. P. (1976). Early Cenozoic calcareous nannoplankton biogeography of the Atlantic Ocean. Marine Micropaleontology. 1: 119-194. gs

    Varol, O. (1989c). Palaeocene calcareous nannofossil biostratigraphy. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications. Ellis Horwood, Chichester 265-310. gs


    Neochiastozygus imbriei compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-7-2019

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    Short stable page link: Go to to create a permanent copy of this page - citation notes

    Comments (1)

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    Rui da Gama

    Broad and narrow elliptical forms are herein included as N. imbriei. Also, there seems to be significant variations in size... Could we consider subdividing this group further?

    Jeremy Young (Tonbridge, UK)

    Hi Rui - sorry for a slow reply, that is a bit outside my expertise. Personally I have enough problems with the existing taxonomy not to want to encourage splitting further, and the coccospheres from Paul Bown show a lot of coccolith variation which again makes me cautious. Neochiastozygus is an interesting group though, and it would be nice if someone could find some good material and do a detailed study. Indeed with good material it could make a good masters project.


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