Nannoconus abundans


Classification: Mesozoic -> Braarudosphaerales -> Nannoconaceae -> Nannoconus -> N. abundans group -> Nannoconus abundans
Sister taxa: N. abundans, N. alvus, N. borealis, N. concavus, N. inornatus, N. troelsenii,

Distinguishing features: Cylindrical nannoconids with apical flange. A smaller flange may also be present at the basal end. Wall cycles are thin and low angled, and the canal is relatively narrow.


Taxonomy:

Citation: Nannoconus abundans Stradner and Grün, 1973
Rank: Species
Variants: Specimen with flanges at both ends occur, and have been termed N. sp. cf. abundans
Notes & discussion: Nannoconus inornatus Rutledge and Bown, 1996

Farinacci & Howe catalog pages: Nannoconus abundans *

Distinguishing features: Cylindrical nannoconids with apical flange. A smaller flange may also be present at the basal end. Wall cycles are thin and low angled, and the canal is relatively narrow.


Morphology remarks: There is variation in the development of vertical ribbing; some forms are highly ribbed, appearing scalloped in end view, while others are smooth-sided and appear perfectly circular in end view. Similar forms with no flanges are called N. inornatus.

Ecology & Biogeography: Mainly Boreal (North Sea Basin) distribution.

Geological Range:
Last occurrence (top): in mid part of BC17 zone (50% up, 126.4Ma, in Barremian stage). Data source: Bown et al. 1998, fig. 5.3
First occurrence (base): at base of BC13 zone (0% up, 130.8Ma, in Barremian stage). Data source: Bown et al. 1998 - zonal marker

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: N. abundans group

    References:

    Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

    Covington, J. M. & Wise, S. W. (1987). Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep-sea fan complex: Deep Sea Drilling Project Leg 93 Site 603, lower continental rise off Cape Hatteras. Initial Reports of the Deep Sea Drilling Project. 93: 617-660. gs

    Rutledge, D. & Bown, P. R. (1996). New names for old: taxonomic clarification of some Early Cretaceous nannofossil marker-species. Journal of Nannoplankton Research. 18: 53-59. gs

    Stradner, H. & Grün, W. (1973). On Nannoconus abundans nov. spec. and on laminated calcite growth in Lower Cretaceous nannofossils. Verhandlungen der Geologischen Bundesanstalt (Wien). 2: 267-283. gs


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    Nannoconus abundans compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-12-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10720 Go to Archive.is to create a permanent copy of this page - citation notes



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