Cruciplacolithus intermedius


Classification: Coccolithophores -> Coccolithales -> Coccolithaceae -> Cruciplacolithus -> Cruciplacolithus intermedius
Sister taxa: C. neohelis, C. kanungoi, C. cruciformis, C. flavius, C. klausii, C. nishii, C. tarquinius, C. asymmetricus, C. edwardsii, C. frequens, C. intermedius, C. primus, C. subrotundus, C. tenuis, C. filigranus, C. inseadus, C. latipons, C. sp.,

Taxonomy:

Citation: Cruciplacolithus intermedius van Heck & Prins, 1987
Rank: Species

Distinguishing features: Moderate to large (>7 µm) Cruciplacolithus with axially aligned cross bars without feet

Farinacci & Howe catalog pages: Cruciplacolithus intermedius *


Evolution & Phylogeny: Regarded as intermediate between C. primus (smaller) and C. tenuis (with feet)

Search data:
TagsLITHS: placolith, elliptical, RIM: psh-bicyclic, CA: cross, cross-axial,
CSPH: spherical, equant, monomorphic, V-UNITS: distal shield, px-tube, V-prominent, R-UNITS: c-str, ds-tube, prox shield, R-prominent, DETAILS: ca_disjunct, rim-bicyclic, isogyres oblique,
MetricsLith size: 7->12µm;
Sources: size range from van Heck & Prins 1987
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: The fist occurrence of C. intermedius between the first occurrences of C. primus and C. tenuis (Thibault et al. 2018). Thibault et al. (2018) argue that the base of NP2 should be placed at the FO of C. intermedius, but we use the more common placement  of base of NP@ at FO of C. tenuis. On this basis the FO of C. intermedius is within NP1.
Last occurrence (top): within NP4 zone (61.51-63.25Ma, top in Selandian stage). Data source: Perch-Nielsen 1985b
First occurrence (base): in upper part of NP1 zone (70% up, 65.6Ma, in Danian stage). Data source: Thibault et al. 2018 - halfway between FO C. primus and FO C. tenuis.

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: Cruciplacolithus intermedius, synonyms included - Cruciplacolithus intermedius;
  • space-time plot :: Samples map :: Parent: Cruciplacolithus

    References:

    Bown, P. R. (2016). Paleocene calcareous nannofossils from Tanzania (TDP sites 19, 27 and 38). Journal of Nannoplankton Research. 36(1): 1-32. gs

    Okada, H. & Thierstein, H. R. (1979). Calcareous nannoplankton - Leg 43, Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 43: 507-573. gs

    Perch-Nielsen, K. (1977). Albian to Pleistocene calcareous nannofossils from the Western South Atlantic, DSDP Leg 39. Initial Reports of the Deep Sea Drilling Project. 39: 699-823. gs

    Perch-Nielsen, K. (1985a). Cenozoic calcareous nannofossils. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 427-555. gs

    van Heck, S. E. & Prins, B. (1987). A refined nannoplankton zonation for the Danian of the Central North Sea. Abhandlungen der Geologischen Bundesanstalt. 39: 285-303. gs

    Varol, O. (1998). Palaeogene. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 200-224. gs


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    Cruciplacolithus intermedius compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-2-2020

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=386 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (1)

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    Nicolas Thibault (Copenhagen, Denmark)

    FO C. intermedius is given here within NP2 whereas C. tenuis is given as marker for the base of NP2. These informations may add to the confusion made years ago when the NP zonation was erected, and gives the false impression that FO C. intermedius is younger than FO C. tenuis, when it's actually the other way around. As discussed in Thibault et al. (2018, Rev. micropaléontol.), "The base of Martini (1971) nannofossil zone NP2 (or Cruciplacolithus tenuis Zone) has been originally defined by the first occurrence of C. tenuis sensu Hay et al. (1967), which actually corresponds today to specimens included in C. intermedius. Therefore the strict application of the zonation implies that the base of NP2 is defined by the FO of C. intermedius and not by that of C. tenuis which first occurs later in the early Danian". It would be useful that Nannotax mentions this because I've seen the NP1/NP2 zonation unfortunately applied in the two distinct ways in the literature.

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    Jeremy Young (Tonbridge, UK)

    Nicholas

    Thank you for the comment. On Nannotax we use the zonation from TimeScaleCreator and this uses base C. tenuis as base NP2 and places it within Chron C29n. So, to make it clear that the base of C. intermedius is lower than here I have now recorded it as occurring within NP1 - which is not the way you express it but puts int in the right sequence. I've also added some references to your paper.

    Jeremy

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